I

SOUTHWESTERN TREES

A Guide to the Native Species of

New Mexico and Arizona

Agriculture Handbook No. 9

UNITED STATES DEPARTMENT OF AGRICULTURE

Forest Service
SOUTHWESTERN TREES

A Guide to the Native Species of

New Mexico and Arizona

By

ELBERT L. LITTLE, JR., Forester (Dendrology)

FOREST SERVICE

Agriculture Handbook No. 9

U. S. DEPARTMENT OF AGRICULTURE DECEMBER 1950

Reviewed and approved for reprinting August 1968

For sale by the Superintendent oí Documents, U.S. Government Printing Office

Washington, D.C. 20402 -
CONTENTS

Page

Introduction . 1

Vegetation of New Mexico and

Arizona 4

Forests of New Mexico and

Arizona 9

How to use this handbook 10

Pine family (Pinaceae) .-..,.. 10

Palm family (Palmae) 24

Lily family (Liliaceae) 26

Willow family (Salicaceae) .... 31

Walnut family (Juglandaceae) . . 42

Birch family (Betulaceae) .... 44

Beech family (Fagaceae) .... 46

Elm family (Ulmaceae) 53

Mulberry family (Moraceae) ... 54

Sycamore family (Platanaceae) . 54

Rose family (Rosaceae) 55

Legume family (Leguminosae) . . 63

Rue family (Rutaceae) 73

Ailanthus family (Simaroubaceae) 74

Bursera family (Burseraceae) . . 75

Page

Spurge family (Euphorbiaceae) . 76

Cashew family (Anacardiaceae) . 78

Bittersweet family (Celastraceae) 79

Maple family (Aceraceae) .... 80

Soapberry family (Sapindaceae) . 82

Buckthorn family (Rhamnaceae) . 83

Sterculla family (Sterculiaceae) . 86

Tamarisk family (Tamaricaceae) . 86

Allthorn family (Koeberliniaceae) 88

Cactus family (Cactaceae) .... 88

Dogwood family (Cornaceae) . , 95

Heath family (Ericaceae) .... 96

Sapote family (Sapotaceae) ... 97

Olive family (Oleaceae) 98

Nightshade family (Solanaceae) . 101

Bignonia family (Bignoniaceae) . 102

Honeysuckle family (Caprifoliaceae) 103

Selected references 104

Index of common and scientific

names 106

11
SOUTHWESTERN TREES

A Guide to the Native Species of

New Mexico and Arizona

INTRODUCTION

The Southwest, where the low, hot, barren Mexican deserts meet

the lofty, cool, forested Rocky Mountains in New Mexico and Arizona, has an unsuspected richness of native trees. The deserts are

not really treeless but contain here and there, scattered along the

drainages and rocky slopes, strange spiny dwarf trees, such as

yuccas, paloverdes, and cacti, found nowhere else in the United

States. On foothills and mesas are broad zones of orchardlike woodlands of pinyons, junipers, and evergreen oaks. At higher elevations are mountain ranges and high plateaus, clothed with valuable

forests of tall pines, spruces, and firs. Within these extensive

timberlands of New Mexico and Arizona are located thirteen national forests and the largest area of continuous virgin ponderosa

pine forests in the West.

Though most States have illustrated popular handbooks of their

native trees. New Mexico and Arizona have not been so fortunate.

Wooton's Trees and Shrubs of New Mexico, published in 1913 and

illustrated with habit photographs of the most important species,

has long been unavailable. The excellent Manual of Southwestern

Desert Trees and Shrubs, by Benson and Darrow, published in

1945 but now out of print, contains drawings or photographs of

nearly all the desert trees in New Mexico and Arizona but omits the

timber species of the mountains.

A nontechnical, fully illustrated guide to southwestern trees

without the numerous shrubs is needed. It should be useful particularly in connection with the national survey of forest resources

being conducted by the Forest Service. Moreover, as the forests

of New Mexico and Arizona are largely in national forests and as

these States do not maintain separate forestry organizations, it

seems logical that the Forest Service, United States Department of

Agriculture, issue this publication.

^ The purpose of this handbook is to present nontechnical descriptions and drawings of the native and naturalized tree species of

New Mexico and Arizona, the fourth and fifth largest States in the

United States. The term Southwest, as used here, refers to these

two States, which comprise the geographical area served by the

Southwestern Region of the Forest Service, However, this handbook includes nearly all the tree species in portions of bordering

States having similar vegetation and should be useful in the Trans-
2 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Pecos region of southwestern Texas, Colorado, Utah, Nevada except the western border, southeastern California, and areas along

the northern boundary of Mexico,

An attempt is made here to answer the question, "What tree is

that ?" Technical botanical terms have been omitted as far as possible in order to make this publication useful to all who want to become better acquainted with the native trees. Many cultivated

and ornamental trees will be found here, although trees from foreign lands have not been included. It is hoped that tourists and

visitors to the Southwest, as well as residents, may find this guide

of interest.

Naturally the division between trees and shrubs is gradual,

especially in the desert, and the number of species recognized as

trees depends upon the definition accepted. Trees are considered

here as woody plants having one well-defined perennial stem or

trunk at least 2 inches in diameter at breast height, a height of at

least 10 feet, and a somewhat definitely formed crown of foliage.

Several shrubby species, only rarely becoming trees, are included.

About 10 additional species of large shrubs reported to reach tree

size in the Southwest have been omitted because information about

them is inadequate. Species sometimes becoming trees in other

States but only shrubby in the Southwest have been excluded.

In this handbook are descriptions and drawings of 132 species of

native trees of New Mexico and Arizona and 3 naturalized species,

together with notes on several other species and important botanical varieties, and drawings of 2 varieties. Both common and

scientific names approved by the Forest Service, as well as other

names and botanical synonyms in use, are listed. The sizes refer

to trees growing in the Southwest, and trunk diameters are measured at breast height (4V^ feet). Notes on abundance, habitat,

vegetation zone, altitudinal limits, geographical distribution within

New Mexico and Arizona, general range, uses, and other matters

of interest are given for each species. The illustrations show leaves

and fruits and in some cases other details or, for a few species such

as yuccas and large cacti, habit sketches. Scales of all drawings,

mostly reduced from natural size, are indicated.

Of these tree species 99 are found in New Mexico and 126 in

Arizona, while 90, or two-thirds of the total, occur in both States.

These southwestern trees are classified into 60 genera and 32 plant

families, but 14 families are represented by only a single tree

species each. Families with greatest numbers of tree species in

New Mexico and Arizona are: pine family, 18 species; willow

family, 17; legume family, 15; rose family, 13; and beech family

(the oaks), 12. The largest tree genera here are: oaks (Querctts)

and willows (Salix), 12 species each; pines (Pimcs), 8 species;

yuccas (Yucca), cottonwoods (Populus), and ashes (Fraxinus),

5 species each; and junipers (Juniperus), cherries (Prunus), and

chollas (Opuntia), 4 species each.

According to geographic distribution, southwestern trees may

be arranged in several groups. Most coniferous and other trees of

the high mountain forests, such as ponderosa pine, Douglas-fir, and

aspen, are widespread in the Rocky Mountains and extend southward to the Southwest. Another and more prominent group of
SOUTHWESTERN TREES 3

desert trees and others, chiefly of lower elevations, is southwestern

and Mexican, from southwestern Texas and northern Mexico northward into southern New Mexico and central Arizona or beyond to

southwestern Utah, southern Nevada, and southeastern California.

Gray oak, catclaw acacia, and desertwillow are illustrations. An

interesting division includes the trees of the Mexican border region

which barely reach mountains in the extreme southwestern comer

of New Mexico (Hidalgo County) and the southeastern corner of

Arizona (Cochise, Santa Cruz, and Pima Counties). Examples are

Apache pine, Mexican blue oak, and Arizona madrone.

A very small group of trees of the short-grass plains, such as

plains cottonwood and little walnut, enter eastern New Mexico from

the east. A few shrubby tree species of the California chaparral,

such as sugar sumac, hollyleaf buckthorn, and California fremotia,

are present also in the chaparral zone of central Arizona. Some

trees of middle elevations, such as pinyon, one-seed juniper, and

velvet ash, have their ranges centering in these two States.

Desert trees chiefly are limited to one or more of the four southwestern desert regions characterized by creosotebush and mesquite: (1) The Chihuahuan desert in southern New Mexico, mostly

in Tularosa Basin and Rio Grande basin (Torrey yucca) ; (2) the

Arizona desert of southern and central Arizona (saguaro) ; (3)

the Colorado desert of southwestern Arizona (smokethorn) ; and

(4) the Mojave desert of northwestern Arizona (Joshua-tree).

Trees deñnitely established as naturalized in New Mexico and

Arizona are limited to three hardy shrubby species, French tamarisk, tree tobacco, and castor-bean. Two others, American plum and

Jerusalem-thorn, are commoner as escapes than native. Several

species are noteworthy for their great rarity or very local distribution in the Southwest ; for example, bristlecone pine, California

washingtonia, Knowlton hophornbeam, chinquapin oak, California

redbud, California fremontia, and Gregg ash.

Two tree species Lowell ash and Kearney sumac are confined to

Arizona, so far as known, although the latter may be expected

to occur also across the Mexican boundary. The following nine

species, mostly of the desert zone, are found in the United States

only in Arizona but are native also in northern Mexico: Toumey

oak, littleleaf lysiloma, fragrant bursera, jumping-bean sapium,

bitter condalia, organpipe cactus, senita, staghorn cholla, and

desert-olive forestiera.

Several publications have been especially helpful in the preparation of this handbook. These are included in the Selected References, which may be consulted for further information about the

trees of New Mexico and Arizona. Sargent's Manual of the Trees

of North America, the standard work describing and illustrating

the trees of the United States, is a valuable reference containing

nearly all the native southwestern trees. The distribution notes of

this handbook have been compiled chiefly from Wooton and Standley's Flora of New Mexico, Kearney and Peebles' Flowering Plants

and Ferns of Arizona, and Benson and Darrow's Manual of Southwestern Desert Trees and Shrubs. However, a few range extensions

have been added here.
4 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Specimens of southwestern trees in the Forest Service Herbarium and United States National Museum, both in Washington,

D. C, have been examined. Grateful acknowledgment is due the

latter for the loan of many specimens for preparation of illustrations.

The drawings in this handbook have been made by Miss Leta

Hughey, scientific illustrator (botany), of the Forest Service. Various persons, particularly Forest Service personnel and botanists in

New Mexico and Arizona, have reviewed the preliminary draft of

the manuscript and have contributed useful notes and suggestions

as well as records of additional tree species and localities. Leslie N.

Goodding has supplied information on several usually shrubby

species rarely reaching tree size, which have been included here

as trees. Carleton R. Ball has reviewed the manuscript on the

willows (genus Salix) and has made many constructive suggestions

on the treatment of this difficult group. A list of the trees of

Lukachukai Mountains in Apache County, northeastern Arizona,

has been furnished by George J. Goodman. The author was in

research work with the Forest Service in Arizona and New Mexico

for eight years.

The Forest Service will welcome further information about

southwestern trees, including corrections and suggestions, additional tree species, range extensions, etc. (Address Chief, Forest

Service, Washington 25, D. C.) Records of giant individual trees

of each species, including their location, height, diameter at breast

height, and crown spread will be of interest. Similar information

is desired about exceptional individuals reaching tree size in species

hitherto known only as shrubs or reported to become trees. Also,

notes on establishment of planted trees as naturalized are worthy

of record.

The Regional OflSce of the Forest Service for the Southwestern

Region, comprising the 13 national forests of New Mexico and

Arizona, is located at Albuquerque, N. Mex. (Post Office Building).

Inquiries and requests for publications about the forests of these

two States should be addressed to that office. The Forest Service

maintains in the same region a research organization conducting

forestry, range, and watershed investigations, the Southwestern

Forest and Range Experiment Station, with headquarters at Tucson, Ariz.

VEGETATION OF NEW MEXICO AND ARIZONA

Most species of southwestern trees have a geographic and altitudinal distribution which follows closely the extent of one or more

zones or types of natural vegetation. Therefore, a summary of the

vegetation with maps may assist identification and further study

of these trees.

The distribution of plant life, or vegetation, over the earth's surface is dependent upon the interaction of various external factors,

such as climate (temperature and rainfall), topography and soil,

other living things including man, and fire. Forests occur where

there is a long, warm, moist growing season and where the soil is

moist throughout the year. Grasslands are found generally where
SOUTHWESTERN TREES 5

most of the rainfall is in the growing season and where low moisture or a dry season prevents tree growth. Deserts, with their

sparse vegetation, are warm or hot regions where moisture is insufficient to support dense growths of trees or grass.

Within the broad climatic zones (tropical, temperate, and frigid),

topography is important. A difference in elevation (altitude) of

1,000 feet affects climate and distribution of plant and animal life

in about the same way as a distance north or south (latitude) of

300 miles at sea level. Thus, the summit of a mountain peak a mile

above its base may have vegetation like that at low levels about

1,600 miles northward.

In the Southwest variations in climate and topography are extreme. Elevations in New Mexico range from 2,876 feet above sea

level where the Pecos River leaves the southern border in the

desert zone to 13,306 feet on the cold, barren, alpine summit of

North Truchas Peak in the Sangre de Cristo Range. The southwestern comer of Arizona, elevation only 100 feet, has subtropical

desert plant life, while San Francisco Mountain, elevation 12,655

feet, has a timber line and tundra vegetation.

The principal types of natural vegetation in New Mexico and

Arizona are summarized in table 1. Merriam's Life Zones, which

were formulated in a study of the San Francisco Mountain area

in northern Arizona in 1889, are listed in parentheses because of

their wide use. For each type the characteristic plants, approximate elevation limits, annual precipitation, and main areas are

stated. Further descriptions of the vegetation may be found in

several of the references listed, such as Bailey, Benson and Darrow,

Kearney and Peebles, Nichol, and Pearson.

The vegetation map of Arizona (fig. 1) is taken from A. A. Nichol

(Ariz. Univ. Agr. Expt. Sta. Tech. Bui. 68.1937) and was prepared

at the University of Arizona with the cooperation of the Forest

Service and Soil Conservation Service. The vegetation map of New

Mexico (fig. 2), is from Byron Hunter, P. W. Cockerill, and H. B.

Pingrey (N. Mex. Agr. Expt. Sta. Bui. 261, fig. 6. 1939), and is

based largely on Forest Service data. It was prepared by Kenneth

W. Parker, and has been supplied by the Bureau of Agricultural

Economics of the United States Department of Agriculture.

A representative southwestern mountain peak may have the

following zones or belts of vegetation on its slopes: Grassland,

pinyon-juniper woodland, ponderosa pine forest, Douglas-fir forest, spruce-fir forest, and alpine tundra. These zones, of course,

are not sharply limited but blend into one another. Rainfall generally increases with elevation. Vast plains lack water and are

treeless, while the higher mountains rising upward from grassland

or desert have a lower timber line and are forested above.

The elevation of the different zones naturally increases slightly

from the northern to southern parts of these large States. On a

mountain the lower zones extend highest on the relatively warmer

and drier southern and southwestern exposures, while the higher

zones project lowest on northern and northeastern slopes and in

cool, shaded canyons. Zones are lower where rainfall is high and

rise on plateaus or similar broad uplands.
TABLE 1.—Principal vegetation types in New Mexico and Ariaona Ci

Ö

O

o

o

Ö

>

O

>

O

O

c3

tr«

C3

Name of vegetation type

Alpine tundra (ArcticAlpine Life Zone).

Spruce-fir forest (subalpine forest, Hudsonian and Canadian

Life Zones).

Douglas-fir forest (montane forest, Canadian Life Zone).

Ponderosa pine forest

(Transition Life Zone)

Pinyon-juniper woodland

(Upper Sonoran Life

Zone).

Oak woodland (Upper

Sonoran Life Zone).

Chaparral (Upper Sonoran Life Zone).

Characteristic plants

Mountain avens, alpine

sedges, alpine grasses.

Engelmann spruce, alpine fir, corkbark fir.

Douglas-fir, white fir,

quaking aspen, limber

pine.

Ponderosa pine, Arizona

pine.

Pinyon, Utah juniper,

one-seed juniper, alligator juniper. Rocky

Mountain juniper.

Emory oak, gray oak,

Mexican blue oak,

Arizona white oak.

Shrub live oak, manzanitas, sumacs, cliifrose, ceanothuses.

Elevation

(feet)

11,500-13,306

8,500-12,000

8,000-9,500

5,500-8,500

4,500-7,500

4,500-6,000

4,000-5,500

Annual

rainfall

(inches)

30-35

30-35

25-30

19-25

12-20

12-20

13-25

Location in

New Mexico

Above timber line of

summits of Sangre de

Cristo Range and

Jemez Mountains in

northern part.

High mountains, especially Sangre de

Cristo Range, Jemez,

Sacramento, and Mogollón Mountains.

High mountains in western two-thirds.

Mountains in western

two-thirds and northeastern corner.

Plateaus, foothills, and

mountains except

eastern quarter.

Foothills and mountains

in southern quarter.

None

Location in

Arizona

Above timber line on

summit of San Francisco Mountain.

High mountains, especially White Mountains, San Francisco

Mountain, and Kaibab

Plateau.

High mountains in eastern and northern

parts.

Mountains and plateaus

in northeastern half.

Plateaus and mountains

in northeastern half.

Foothills and mountains

in southeastern and

central parts.

Mountains in central

part.
Oak brush (shinnery,

Upper Sonoran Life

Zone).

Short grass (plains

grassland, Upper

Sonoran Life Zone).

Desert grass (semidesert

grassland, Lower

Sonoran Life Zone).

Sagebrush (northern

desert. Upper Sonoran Life Zone).

Desert (semidesert

shrub. Lower Sonoran Life Zone).

Havard oakBlue grama, hairy

grama, galleta, buffaBlack grama, tobosa,

dropseeds.

Big sagebrush, blackbrush.

Creosotebush, mesquite,

tarbush, catclaw

acacia, paloverdes,

bur-sages, cacti,

desert saltbush.

3,600-4,800

4,500-6,500

3,000-5,000

2,500-6,000

100-4,500

13-18

9-20

9-18

7-17

3-15

Southeastern corner

Plains, mostly in eastern, central, and

northern parts.

Plains in southwestern

half.

Scattered near northern border.

Plains and valleys of

southern third.

None.

Plains and plateaus in

northern part.

Plains in southeastern

part.

Plateaus of northern

quarter.

Southwestern half and

bottom of Grand

Canyon.

O

Cl

m

H

m

to
8 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

ARIZONA

Ponderoso pine forest

(including Oouqios-fif

ond spruce-fir forests)

Pinyon-juniper woodlond

Oak woodland and

chaparral

LEGEND

1 1 Short gross

LH_J Desert gross

L="-j Sogebrush

H Irrigoted land

Desert (creosotebusti,

desert saltbush)

Oeserf (mesquitesoltbush bottom^

Desert ( pGloverde,

cocti, bur-söge )

Figure 1.—Principal vegetation types in Arizona.
SOUTHWESTERN TREES

NEW MEXICO

[ J Short grass

rry^ Semidesert

^ ' '■■^'' shrub

c-ni Woodt^ land

I Irrigated

Figure 2.—Principal vegetation types in New Mexico.

FORESTS OF NEW MEXICO AND ARIZONA

Most of the trees of New Mexico and Arizona are found within

the vegetation types of forest and woodland, though smaller numbers of trees representing many species are scattered in other types

or along streams. The woodlands, both pinyon-juniper and oak,

contain small trees usually not of commercial value for lumber,

while the coniferous forest types of ponderosa pine, Douglas-fir,

and spruce and fir at higher elevations constitute the saw-timber

area, with large trees suitable for logging operations.

Forests and woodlands combined cover about 25.7 percent of the

area of New Mexico and 26.8 percent of Arizona, or more than onefourth of each State. Saw-timber forests alone occupy about 7.8

percent of New Mexico and 6.5 percent of Arizona. A considerable

part of the saw-timber area, however, is noncommercial, that is,

too inaccessible or too scattered for logging or has been withdrawn
10 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

for other purposes. The volume of commercial saw timber in New

Mexico is estimated at 8,471,000,000 board feet and in Arizona,

16,270,000,000 board feet.

Four coniferous species, or softwoods, together account for 98

percent of the total saw timber in New Mexico and Arizona. Ponderosa pine makes up 82 percent ; Douglas-fir, 10 percent ; white fir,

3 percent; and Engelmann spruce, 3 percent. Limber pine, alpine

fir (including corkbark fir), and other species have small quantities

of saw timber.

The forested areas of New Mexico and Arizona are valuable in

many ways. Besides providing saw timber, fence posts, fuel, and

other wood products, they support large numbers of livestock,

game, and wildlife. They yield minerals and also supply the water

which makes agriculture and settlements possible in the drier lowlands. The plant cover on mountain slopes regulates stream flow,

prevents disastrous floods, and reduces the silting of reservoirs.

The undisturbed forest areas with their great scenic beauty attract

numerous visitors to the Southwest on outings and vacations in

both summer and winter and have an inestimable value for

recreation.

HOW TO USE THIS HANDBOOK

It is easy to identify most of the native trees of your locality by

reference to the drawings, descriptions, and distribution notes. If

you know a common name, just consult the index for page numbers and then match your tree or specimen with the illustrations

and text. If your specimen is a pine, it may be necessary to look

at the drawings of all eight species of pines to find the complete

name, for example. Identification is quicker and more certain if

fruits or flowers, as well as leaves, are present.

Many southwestern trees can be identified almost as easily in

winter as in summer. Some, such as conifers, yuccas, and most

oaks, are evergreen and bear leaves at all times. Others, including

cacti, paloverdes, and certain other spiny desert species, are leafless

most of the year. When a broadleaf tree is to be identified in

leafless, winter condition, a search frequently will reveal a few^

old fruits still attached on the twigs and old leaves and fruits on

the ground underneath.

Pine Family (Pinaceae)

MEXICAN PINYON (Pinus cemhroides Zuce.)

Also called nut pine, pinyon pine, Mexican pinyon pine.

Description: Small, needle-leaf evergreen tree 15 to 30 feet or

more in height, with trunk 114 feet or more in diameter and with

compact, rounded, spreading crown. Needles 3 in a bundle, 1 to 1%

inches long, slender, dark blue green. Cones egg-shaped, 1 to 1^/9

inches long, light brown, with thick blunt scales and hard-shelled",

brown seeds % inch long, oily and edible and known as pinyon

nuts. Bark deeply furrowed into scaly ridges, reddish brown or

blackish, on large trunks with flattened plates. Wood soft, heavy,

resinous, yellow.
SOUTHWESTERN TREES 11

Mexican pinyon. Pinyon. Singleleaf pinyon. Bristlecone pine.

Distribution: Characteristic and common tree of the pinyonjuniper woodland, associated with junipers and oaks, 5,000 to

7,500 feet elevation, in mountains along the Mexican border. New

Mexico: mountains of southwestern corner in Hidalgo and Grant

Counties. Arizona: mountains of southeastern part, from Cochise

and Greenlee Counties west to Pima and Santa Cruz Counties. Also

in northern and central Mexico.

Mexican pinyon differs from the common pinyon in its thinner

needles in 3's which (in the form present in the United States) lack

the whitish lines on the outer surface, in its smaller cones with

smaller, hard-shelled seeds or nuts, and in its more southern,

limited range along the Mexican border. Though they are extensively gathered and eaten in Mexico, Mexican pinyon nuts are of

no economic importance in the United States. The small seeds are

seldom produced in quantity and are too hard to be cracked with

the teeth. The pitchy wood is suitable for fuel.

PINYON {Pinus edulis Engelm.)

Also called nut pine, pinyon pine, Colorado pinyon pine. Botanical synonym: P. cembroides var. edulis (Engelm.) Voss.

Description: Small, bushy, needle-leaf evergreen tree 15 to 35

feet tall, with short trunk 1 to 2 feet or more in diameter, and

with compact, rounded, spreading crown. Needles 2 (sometimes 3

or 1) in a bundle, 1 to 2 inches long, stout, yellow green. Cones

egg-shaped, II4 to 2 inches long, light brown, with thick blunt

scales and large brown seeds I/2 inch long, oily and edible and

known as pinyon nuts or piñones. Bark furrowed into scaly ridges,

gray to reddish brown. Wood soft, heavy, resinous, yellow.

Distribution: The abundant and characteristic tree of the

pinyon-juniper woodland zone, growing in pure stands or with

junipers on dry rocky foothills, mesas, plateaus, and lower mountain slopes between the deserts and forests, mostly from 5,000 to

7,000 feet elevation, widely distributed. New Mexico : northeastern

corner and western two-thirds. Arizona : mountains and plateaus of

northeastern third, from Greenlee County find northeastern corner

west to Kaibab Plateau and Hualpai Mountains and south to
12 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Yavapai and Gila Counties. Southwestern Texas, extreme northwestern Oklahoma, and Colorado, west to southwestern Wyoming,

Utah, Arizona, and southeastern California. Also in northern

Mexico.

Pinyon, the State tree of New Mexico, is one of the most abundant and most widely distributed tree species in the Southwest.

It grows in pure stands or with one or more of four kinds of

junipers and covers vast areas. On the south rim at Grand Canyon

National Park it is the commonest tree species. A form with the

needles single as in singleleaf pinyon but relatively more slender

and shorter occurs in central Arizona along the lower limit of the

woodland zone north to Grand Canyon. Pinyon is one of the most

drought-resistant and slowly growing species of pines, requiring

only 12 to 18 inches of rainfall a year. Because of the scarcity of

moisture, these dwarf trees do not form dense forests but grow

scattered in open woodlands resembling old orchards.

The familiar seeds, known as pinyon nuts, piñones, and Indian

nuts, are a wild, commercial nut crop, delicious raw or roasted and

also sold shelled and in candies. Pinyon ranks first among the

native nut trees of the United States not also under cultivation.

Every autumn Navajo Indians, Spanish-Americans, and others

harvest more than a million pounds of pinyon nuts, which are

shipped to New York City and other eastern markets. Thus pinyon

nuts furnish supplementary income to persons living near the

woodlands as well as food to city dwellers. The pitchy wood is good

for fuel and is used locally for mine timbers and fence posts but is

not durable unless treated. Pinyons are sometimes planted as ornamentals within their range, where they are hardy but of very

slow growth unless irrigated.

SINGLELEAF PINYON (Pinus monophylla Torr. & Frém.)

Also called nut pine, singleleaf pinyon pine. Botanical synonym :

P. cembroides var. monophylla (Torr. & Frém.) Voss.

Description: Small, spreading, needle-leaf evergreen tree 1.5 to

30 feet or more in height, with trunk 1 foot or more in diameter.

Needles 1 in a sheath, 1 to 2 inches long, stout and stiff, gray

green. Cones egg-shaped, 2 to 3 inches long, light brown, with

thick blunt scales and large, thin-shelled, brown seeds % inch

long, edible and known as pinyon nuts and pine nuts. Bark furrowed into scaly ridges, dark brown. Wood soft, heavy, yellowish

brown.

Distribution: Local in pinyon-juniper woodland with Utah juniper, 4,500 to 6,500 feet elevation, in mountains of northiñ^estern

corner of Arizona ; not in New Mexico. Arizona : Virgin Mountains

(northwestern Mohave County) and perhaps elsewhere in extreme

northwestern corner of State. Also in western Utah, southern

Idaho, Nevada, California, and Lower California, Mexico.

Singleleaf pinyon, the State tree of Nevada, is a characteristic

tree of the pinyon-juniper woodland in the Great Basin region,

replacing the species of pinyon in the Southwest. The pinyon of

central Arizona with needles single, though usually called single-
SOUTHWESTERN TREES 13

leaf pinyon, is more properly placed as a form of the common 2-

needle pinyon (Pinus edulis), according to the seeds and other

characteristics.

The nuts of singleleaf pinyon, which are gathered by Indians

and sold locally on a small scale, differ from the common pinyon

nuts of the Southwest in being larger, thinner shelled, and mealy

rather than oily in flavor. The wood is used for fuel.

BRISTLECONE PINE (Pinus aristata Engelm.)

Also called foxtail pine.

Description: Small needle-leaf evergreen tree 40 feet or less

in height and up to 21/2 feet in trunk diameter, with broad, irregular crown and spreading branches, or a low bushy shrub at the

timber line. Needles numerous and densely crowded, 5 in a bundle,

1 to 11/2 inches long, stout, dark green, curved and pressed against

the twig and not spreading out, remaining attached 10 to 15 years

and forming brushlike or "foxtail'* masses along the ends of the

branches. Cones 2V2 to 4 inches long, dark purplish brown, each

scale with a slender prickle nearly % inch long. Bark on small

trunks and branches smooth and whitish, on larger trunks becoming irregularly fissured, scaly, and reddish brown. Wood soft,

moderately heavy, brownish red.

Distribution: Very local and widely scattered, in open grassy

stands or in spruce-fir forest up to timber line, 9,700 to 11,500

feet elevation, on the highest mountains of northern New Mexico

and Arizona. New Mexico: highest peaks of Sangre de Cristo

Range. Arizona: only on San Francisco Mountain near Flagstaff.

Also on high peaks in Colorado, Utah, Nevada, and California.

Bristlecone pine, named from the prickles on the cones, has an

unusual, scattered distribution on widely separated high peaks in

six States. As the trees are small, uncommon, and not accessible,

the wood is seldom used.

LIMBER PINE {Pinus flexilis James)

Also called Rocky Mountain white pine, white pine. Variety:

P. flexilis var. reflexa Engelm. (also called border limber pine,

Mexican white pine ; botanical synonym, P. strobiformis auth.).

Description: Medium-sized, needle-leaved evergreen tree 50 to

80 feet tall and 3 feet or more in trunk diameter, with broad

rounded crown. Needles 5 in a bundle, 2 to 31/2 inches long, slender,

blue green. Cones short-stalked, hanging down, 4 to 8 inches long,

yellow brown, with thick rounded scales bearing seeds % to i^ inch

long. Bark on small trunks smooth and whitish gray, on larger

trunks becoming deeply furrowed and dark brown or gray. Wood

soft, lightweight, pale yellow.

Distribution : Not common but widely distributed in high mountains of Douglas-fir and spruce-fir forests, or less frequently ponderosa pine forest, usually between 7,000 and 10,000 feet elevation ;

with a variety in pine forest as low as 6,500 feet elevation in the

Mexican border region. New Mexico: high mountains of western

two-thirds. Arizona: high mountains of eastern half, west to
14 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Navajo Mountain and San Francisco Mountain and south to Santa

Rita Mountains and Chiricahua Mountains. Widely distributed in

Rocky Mountain region from southwestern Texas to Black Hills

of South Dakota and Montana, west to southern Alberta and

southern British Columbia, and south to California, Arizona, and

northern Mexico.

The variety (var. reflexa) found at lower elevations in the southwestern corner of New Mexico, southeastern Arizona, and northern Mexico, differs from the typical form in larger size, better

developed trunk, absence of whitish lines on outer surface of

needles, and the cone scales with narrow tips curved back.

The wood of limber pine is used for lumber (mostly for rough

construction and occasionally for boxes), mine timbers, railroad

ties, poles, and fuel. However, in the Southwest the limited supply

furnishes only a small amount of lumber and often is cut along

with ponderosa pine. The seeds are edible, though smaller and

thicker shelled than pinyon nuts.

CHIHUAHUA PINE (Pinus leiophylla Schiede & Deppe var.

chihuahuana (Engelm.) Shaw)

Botanical synonym: P. chihvxihiiana Engelm.

Description: Small to medium-sized tree 30 to 80 feet tall and

1 to 2 feet in trunk diameter, with open, spreading crown. Small,

short twigs usually present along the trunk. Needles 3 in a bundle,

2% to 4^4 inches long, slender, pale blue green, with the sheath

at base soon shedding. Cones distinctly stalked and spreading,

egg-shaped, li/^ to 3 inches long, light brown and shiny, the scales

with short, shedding prickles, maturing and opening in 3 years

but remaining attached several years. Bark very thick (2 inches

or more), with deep furrows and broad ridges, dark brown or

nearly black. Wood hard, orange.

Distribution: Common or scattered in pine forest, associated

with Arizona pine and Apache pine, 5,000 to 7,800 feet elevation,

in mountains along the Mexican border. New Mexico : mountains

of extreme southwestern corner. Animas and San Luis Mountains

in Hidalgo County. Arizona: mountains of southeastern corner

north to southern Navajo County and west to Final Mountains in

Gila County and Santa Catahna and Santa Rita Mountains in

eastern Pima County. Also in Mexico.

Chihuahua pine is a northern variety of a widely distributed

Mexican species, the typical form having 5 needles in a bundle.

This species is easily recognized by the many old, open, stalked

cones remaining attached in the branches, by the trunk with very

thick bark and often bearing scattered leafy twigs, and by the

absence of sheaths at base of needles except when young. This is

the only pine native in the United States which requires 3 years

instead of 2 to mature its cones. The three stages of developing

cones usually can be found. Chihuahua pine is one of the few

kinds of pine which will sprout from cut stumps. Because of the

small size and limited distribution, Chihuahua pine is of minor

importance for lumber.
SOUTHWESTERN TREES 15

Limber pine. Chihuahua pine. Ponderosa pine. Apache pine.

PONDEROSA PINE (Pinus ponderosa Laws.)

Also called western yellow pine, yellow pine. Varieties : Arizona

pine (P. ponderosa var. aHzonica (Engelm.) Shaw; also called

Arizona ponderosa pine, Arizona yellow pine; botanical synonym,

P. aHzonica Engelm.). P, ponderosa var. scopuLorum Engelm.

(also called Rocky Mountain ponderosa pine; botanical synonym,

P. brachyptera Engelm.).

Description : Large, needle-leaved evergreen tree 80 to 125 feet

tall with a straight trunk 2 to 3 feet in diameter, or sometimes 150

feet tall and 3V2 feet in diameter or larger. Crown narrow and

open, with spreading branches. Needles usually 3 in a bundle or

occasionally 2 (mostly 5 in the variety Arizona pine), 4 to 7 inches

long, stout, dark green. Cones 3 to 5 inches long (21/4 to 3 inches in

Arizona pine), light reddish brown, with prickly scales, leaving

several scales on the twig when shedding. Bark on small trunks

less than 1 foot in diameter (known as "blackjacks") blackish

and furrowed into ridges, on larger trunks becoming yellow brown

and irregularly fissured into large, flat, scaly plates. Wood hard,

yellowish with whitish sapwood.

Distribution: The commonest forest tree in the Southwest and

the characteristic species of the ponderosa pine forest on the mountains and higher plateaus, in pure stands or associated with Douglas-fir, Gambel oak, limber pine, or pinyon, usually between 5,500

and 8,500 feet in elevation but sometimes beyond these limits,

widely distributed. New Mexico: common at suitable elevations

in mountains of western two-thirds from Guadalupe Mountains

north and west and to northeastern corner, Arizona: high mountains and plateaus in northeastern half, west to Kaibab Plateau

and Hualpai Mountains. Range very extensive in Rocky Mountains

and Pacific coast mountains, from southwestern Texas north in

foothills to western Nebraska, western North Dakota, and Montana, west to British Columbia, and south to California and Arizona. Also in northern Mexico.

Ponderosa pine has one of the greatest ranges of all the trees

in the western mountains and includes minor geographic variations which intergrade. The Rocky Mountain variety, which is
16 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

present over New Mexico, has shorter needles of both 3 and 2 in a

bundle and has smaller cones. More distinct is Arizona pine, a

variety with 5 slender needles in a bundle and with small cones, distributed in mountains along the Mexican border in the extreme

southwestern corner of New Mexico (Hidalgo County), southeastern Arizona (Cochise, Santa Cruz, and Pima Counties), and

northern Mexico. The typical variety with needles in clusters of 3

occurs northward over Arizona but occasionally is found southward

with Arizona pine.

In many places this species grows in pure stands. The vast forest

on the Mogollón Plateau in central Arizona extending into western

New Mexico, about 300 miles long, is the largest continuous virgin

forest of ponderosa pine anywhere in the West.

Ponderosa pine not only is the most valuable saw-timber tree

species of New Mexico and Arizona but is the most important

western pine and is second only to Douglas-fir in total stand among

all the different tree species of the United States. Most of the

lumber produced in the Southwest is from ponderosa pine. The

lumber has many uses, such as building and other construction,

boxes and crates, and millwork ; also caskets, furniture, and toys.

Other products are piling, poles, fence posts, mine timbers, veneer,

railroad ties, and fuel. The trees are planted also in shelter belts

and for ornament. Indians stripped and ate the inner bark of this

and other conifers. Montana has ponderosa pine as its State tree.

APACHE PINE (Pinus latifolia Sarg.)

Also called Arizona longleaf pine. Botanical synonym: P.

apacheca Lemm.

Description: Medium-sized, needle-leaved evergreen tree 50 to

70 feet tall and 2 feet or more in trunk diameter, with open, rounded

crown and with few large branches. Twigs relatively few, stout.

Needles 3 (sometimes 4) in a bundle, 8 to 12 inches long (to 15

inches in seedlings), stout, dark green. Cones 4 to 51/2 inches long,

light brown, with prickly scales, leaving several scales on the twig

when shedding. Bark deeply furrowed, dark brown. Wood hard

and heavy, yellowish.

Distribution: Uncommon and scattered in pine forest, with

Arizona pine, Chihuahua pine, silverleaf oak, and Arizona oak,

5,000 to 8,200 feet elevation, in mountains along the Mexican border. New Mexico : mountains of extreme southwestern corner. Arizona: mountains of southeastern corner, Chiricahua, Huachuca,

and Dragoon Mountains in Cochise County and Santa Rita Mountains in eastern Pima County. Also in adjacent Mexico.

Apache pine is a distinctive species with a rather restricted

range. The seedlings pass through a grasslike stage, reminiscent

of longleaf pine (P. palustris Mill.) of the Southeast; they, with

the very long-needled saplings, are wholly unlike those of any

other western pine. Mature trees, however, are more like the

closely related ponderosa pines, diifering chieñy in the fewer and

stouter twigs with longer needles and the slightly larger cones.

The wood is similar to that of ponderosa pine but not much used

because of the limited supply.
SOUTHWESTERN TREES 17

ENGELMANN SPRUCE {Picea engeltnanni Parry)

Also called white spruce, mountain spruce, silver spruce.

Description: Large, needle-leaved evergreen tree to 80 feet or

more in height, with straight trunk to 3 feet or more in diameter,

and with narrow, pointed conical crown and horizontal or slightly

drooping branches extending nearly to ground; or at timber line

dwarfed and bushy. Twigs roughened by peglike bases of fallen

needles ; twigs and leaf bases usually hairy. Needles 4-angled, %

to ll^ inches long, pointed but not stiif, dark or pale blue green,

with disagreeable odor when crushed. Cones IV2 to 21/2 inches

Jong, light brown, with papery scales more or less rounded and

distinctly thinner at apex. Bark thin, with loosely attached scales

or flakes, grayish.or purplish brown. Wood soft, lightweight, light

yellow to reddish brown.

Distribution : A common and characteristic tree of the sprucefir forest up to the timber line, often growing crowded in dense

stands, pure or mixed with alpine fir, Douglas-fir, white fir, and

blue spruce, usually between 9,000 feet and the timber line up to

12,000 feet elevation but occasionally as low as 8,000 feet, in

higher mountains. New Mexico: higher mountains in western

two-thirds, from Sacramento Mountains and Sangre de Cristo

Range westward. Arizona: higher mountains of northeastern half,

from Chiricahua, Santa Catalina, Pinaleno, and White Mountains

northwest to San Francisco Mountain and Kaibab Plateau. Rocky

Mountain and Pacific Coast regions from New Mexico to Montana,

Alberta, and British Columbia, and south to northern California

and Arizona.

^ Engelmann spruce is an important tree species at higher elevations in mountains of the Southwest, though limited in area and

accessibility. The lumber is used for building construction and

boxes, and the wood is also a source of mine timbers, railroad ties,

and poles. The trees are desirable ornamentals in cool moist climates. This species honors George Engelmann (1809-84), GermanAmerican physician and botanist of St. Louis, an authority on

conifers, yuccas, cacti, and other plant groups.

BLUE SPRUCE {Picea pungens Engelm.)

Also called Colorado blue spruce, Colorado spruce, silver spruce.

Botanical synonym: P. parryana (André) Sarg.

Description: Large, needle-leaved evergreen tree up to 80 feet

tall^ and 2 feet in trunk diameter or larger, with conical crown of

bluish foliage, at least on young trees and parts. Twigs roughened

by peglike bases of fallen needles ; twigs and leaf bases usually not

hairy. Needles 4-angled, % to li/s inches long, stiff and spinepointed, dull blue green or silvery blue or becoming darker on older

parts. Cones 214 to 4 inches long, light brown, with scales more or

less straight across apex and not thinner. Bark rough and thick,

furrowed into scaly ridges, gray or brown. Wood soft, lightweight,

brownish or whitish.

Distribution: Uncommon in spruce-fir forest and Douglas-fir

forest, but sometimes in dense stands, 7,000 to 11,000 feet eleva-
18 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

tion, in higher mountains. New Mexico: higher mountains in

western two-thirds, Sacramento Mountains and Sangre de Cristo

Range westward. Arizona : local at high elevations in eastern and

northern parts, White Mountains and Lukachukai Mountains in

Apache County and Kaibab Plateau in Coconino County. Rocky

Mountain region from New Mexico to Wyoming and southeastern

Idaho, and south to Arizona.

Blue spruce is less common than Engelmann spruce and less

widely distributed, often occurring at slightly lower levels. The

lumber of both species is cut and marketed together. The trees

are extensively planted for ornament because of the bluish, often

silvery, foliage and are used also in shelter belts. Blue spruce is the

State tree of both Colorado and Utah.

DOUGLAS-FIR (Pseudotsuga taxifolia (Poir.) Britton)

Also called Douglas-spruce, red fir, yellow ñr, common Douglasfir, Oregon pine (lumber). Botanical synonyms: P. douglasii (Sabine) Carr., P, mucronata (Raf.) Sudw. Variety: P. taxifolia var.

glauca (Mayr) Sudw. (also called blue Douglas-fir).

Description : The largest native tree of New Mexico and Arizona,

needle-leaved evergreen tree becoming 100 to 150 feet (or 190

feet) in height, with straight trunk 3 to 6 feet or more in diameter,

with open, broadly conical crown and drooping lower branches.

Twigs slightly roughened by bases of fallen needles. Needles

spreading on all sides of twigs or sometimes in 2 rows, shortstalked, flat, % to ll^ inch long, rounded at apex, dark blue green.

Cones 1% to 2% inches long, reddish brown, with thin, rounded

scales and long, distinctive 3-pointed bracts projecting beyond the

scales. Bark rough and very thick, deeply furrowed into broad

ridges, sometimes very corky, dark reddish brown or gray. Wood

soft, lightweight, yellowish with whitish sapwood.

Distribution : Common as the characteristic tree in the Douglasfir forest but also occurring in the ponderosa pine forest and sprucefir forest, 6,500 to 10,000 feet elevation, or as low as 5,200 feet in

canyons, widely distributed in higher mountains. New Mexico:

higher mountains in western two-thirds, from Guadalupe Mountains, Sacramento Mountains, and Sangre de Cristo Range westward. Arizona: higher mountains of northeastern half, west to

Santa Rita and Santa Catalina Mountains, Hualpai Mountains, and

Kaibab Plateau. Widely distributed in Rocky Mountain and Pacific

Coast regions from southwestern Texas to Montana, Alberta, and

British Columbia, and south to California and Arizona. Also in

northern Mexico.

Douglas-fir grows in pure stands or mixed with species of the

next lower and higher forest zones of the mountains. The Rocky

Mountain trees are placed in a separate botanical variety (P.

taxifolia var. glauca (Mayr) Sudw.), which differs from the

typical variety in the Pacific Coast region chiefly in slower growth,

more compact habit, shorter and paler blue-green leaves, and

smaller cones.
SOUTHWESTERN TREES 19

Engelmann spruce. Blue spruce. Douglas-fir. White fir.

The most important timber tree species of the United States,

Douglas-fir ranks first in total stand, lumber production, and production of veneer for plywood. In the Southwest this species is

confined to limited areas in the high&r mountains but ranks second

to ponderosa pine as saw timber. Douglas-fir is cut for its high

quality lumber in localities where it is suflficiently abundant, chiefly

in northern New Mexico and in the Sacramento Mountains. The

wood is used also for rough construction, telephone poles, and railroad ties. Douglas-fir is planted also for shade, ornament, and

shelter belts and is used for Christmas trees. It is the State tree

of Oregon.

This species bears the name of David Douglas (1798-1834),

Scotch botanical explorer, who discovered and introduced to horticulture many species of trees and other plants of the Pacific Northwest.

WHITE FIR {Abies concolor (Gord. & Glend.) Hoopes)

Also called balsam fir, silver fir, white balsam.

Description: Large, needle-leaved evergreen tree to 150 feet in

height and SV^ feet in trunk diameter, with pointed conical crown

becoming irregular in age. Needles spreading and curved upward,

flat, 11/2 to 21/2 inches long, usually blunt, pale blue green or

silvery. Cones in top of tree, upright, 3 to 5 inches long, usually

grayish green, with scales falling apart at maturity. Bark on small

trunks smoothish, gray, becoming very thick, hard, and deeply

furrowed into scaly ridges. Wood soft, very lightweight, whitish or

light brown.

Distribution: Common in ponderosa pine, Douglas-fir, and

spruce-fir forests, 5,500 to 10,000 feet, in high mountains. New

Mexico: high mountains of western two-thirds and northeastern

part from Sacramento Mountains and Mogollón Mountains northward. Arizona: high mountains of northeastern half, west to Santa

Catalina Mountains, Hualpai Mountains, and Grand Canyon. Widely

distributed in Rocky Mountain and Pacific Coast regions from New

Mexico to Wyoming, west to Oregon, and south to California and

Arizona. Also in Lower California, Mexico.
20 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

White fir is associated with other coniferous species in forests

at high elevations. Limited quantities of white fir are cut for lumber in the Southwest, often sold with lumber of other species. The

trees are suitable as ornamentals and shade trees.

ALPINE FIR (Abies lasiocarpa (Hook.) Null.)

Also called white balsam, white fir (lumber). Variety: Corkbark fir (A. lasiocarpa var. arizonica (Merriam) Lemm. ; also

called Arizona fir; botanical synonym, A. arizonica Merriam).

Description: Large, needle-leaved evergreen tree to 90 feet tall

and 3 feet in trunk diameter, or larger ; but dwarfed and shrubby

at timber line. Crown long, narrow, and sharp-pointed, with

branches extending nearly to base of tree. Needles spreading or

sometimes in 2 rows, fiat, 1 to 1% inches long, blunt, or on uppermost branches pointed and shorter, dark blue green. Cones in top

of tree, upright, 2i/^ to 4 inches long, dark purple, finely hairy,

with scales falling apart at maturity. Bark becoming fissured and

scaly, gray ; in the variety corkbark fir, bark soft, spongy or corky,

smoothish, thin, creamy white. Wood soft, lightweight, light

brown.

Distribution: Characteristic, usually common tree of spruce-fir

forest up to timber line, growing with Engelmann spruce, 8,000

to 12,000 feet elevation, in higher mountains. New Mexico : higher

mountains of northern and western parts, from Sangre de Cristo

Range, Sandia Mountains, and Mogollón Mountains westward.

Arizona: higher mountains of eastern and northern parts, from

Pinaleno Mountains, Santa Catalina Mountains, White Mountains,

and Navajo Mountain, west to Kaibab Plateau and San Francisco

Mountain. Widely distributed in Rocky Mountain region from New

Mexico north to Montana, Alberta, British Columbia, Yukon, and

Alaska, and south to Oregon, Nevada, and Arizona.

Corkbark fir, a variety readily distinguished by its peculiar

whitish corky bark, occurs on San Francisco Mountain, Ariz., where

it was first discovered, on Lukachukai Mountains in northeastern

Apache County, and on scattered mountains in southwestern, western, and northern New Mexico and southwestern Colorado. Because

of its attractive, showy bark, it is highly valued as an ornamental

tree.

In the Southwest, alpine fir, including corkbark fir, is too restricted to be of much importance for lumber, though some is cut

in the White Mountains of eastern Arizona and elsewhere. This

species is suitable for ornamentals and Christmas trees.

ARIZONA CYPRESS (Cupressus arizonica Greene)

Also called rough-bark Arizona cypress, smooth cypress, smooth

Arizona cypress. Botanical synonyms: C. glabra Sudw., C, arizonica var. bonita Lemm.

Description: Medium-sized, scale-leaved evergreen tree usually

about 30 feet tall, with straight trunk IV^ feet in diameter, up to

75 feet in height and 3 feet in diameter (maximum about 90 feet

tall and SV^ feet in diameter). Crown conical or rounded. Twigs
SOUTHWESTERN TREES 21

Alpine fir. Arizona cypress. Alligator juniper. Rocky Mountain

juniper.

numerous, stout, 4-angled, branching nearly at right angles in all

directions. Leaves scalelike, Vie long, pale blue green. Cones

short-stalked, % to 1 inch in diameter, hard and woody, gray, with

flattened scales bearing a point in center, remaining attached

several years. Bark variable, on small trunks smoothish and shedding in thin scales to expose dark red inner bark; the form in central Arizona retaining this smoothish red bark on most larger

trunks ; or bark on larger trunks becoming rough and thick, furrowed and fibrous, or checkered, gray or blackish. Wood moderately soft and lightweight, light brown.

Distribution: Very scattered and local, forming groves in canyons and mountains of oak woodland, with evergreen oaks or

junipers, 3,500 to 7,200 feet elevation, mountains of Mexican border region and in central Arizona. New Mexico: San Luis and

San Francisco Mountains in southwestern corner. Arizona : mountains and canyons of southeastern and central parts from Chiricahua Mountains and Greenlee County west to Dragoon Mountains and Santa Catalina Mountains and northwest to Mazatzal

Mountains and Oak Creek Canyon. Also in Chisos Mountains of

southwestern Texas and in northern Mexico.

The form of Arizona cypress in central Arizona is regarded by

some botanists as a separate variety or species, smooth cypress

(C. glabra Sudw.). It is distinguished by the smoothish outer bark

shedding or peeling and exposing the dark red inner bark, though

the largest trees have thick, furrowed, gray bark. This form is

widely cultivated in warm, dry regions as a symmetrical ornamental evergreen with bluish-green foliage and is planted also in

shelter belts. It is also grown for Christmas trees in the South,

The wood of Arizona cypress is used for fence posts but is too

scarce to be lumbered.

The cypresses (genus Cupressus), though widely distributed in

the Old World, are found in the New World only in southwestern

and western United States from Texas to California and Oregon

and from Mexico south to Costa Rica. The native species (about

8) in the United States all are of restricted and scattered distribution, suggesting that they may be of great antiquity and
22 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

relics of former widespread occurrence. The best groves should

be preserved in their natural condition before the larger trees are

cut. Some fine specimens of Arizona cypress are already under protection in the Chiricahua National Monument, in southeastern

Arizona.

ALLIGATOR JUNIPER (Juniperus deppeana Steud.)

Also called western juniper (lumber). Botanical synonyms:

/. pachyphloea Torr.; /. deppeana var. pachyphloea (Torr.) Martinez.

Description: Medium-sized, scale-leaved evergreen tree usually

20 to 40 feet tall with a large, short trunk 2 to 3 feet in diameter,

reaching a maximum height of 65 feet and a trunk diameter of 7

feet. Crown rounded and spreading or in age irregular and partly

dead. Leafy twigs Via to y32 inch in diameter. Older twigs reddish

brown and nearly smooth, peeling off. Leaves scalelike, Vie long,

blue green, glandular, mostly with a whitish resin drop or gland,

or on leading twigs needlelike, up to l^ inch long, pale or whitish.

"Berry" i/^ inch in diameter, bluish or brownish, covered with a

bloom, hard and mealy, 3- or 4-seeded, maturing the second year.

Bark thick and rough, deeply furrowed into checkered or square

plates, gray or blackish, suggesting the back of an alligator.

Wood soft, lightweight, light red with narrow whitish sapwood.

Distribution: Common but usually scattered on hillsides and

mountains in oak woodland, pinyon-juniper woodland, and lower

part of ponderosa pine forest, 4,500 to 8,000 feet elevation. New

Mexico : mountains in southern and western parts, from Guadalupe

Mountains and Capitán Mountains west to Black Range and north

to Mount Taylor and Zuni Mountains. Arizona: mountains of

southeastern and central parts, west to Flagstaff and to Baboquivari Mountains. Also in southwestern Texas and northern and

central Mexico.

Alligator juniper, the largest juniper in New Mexico and Arizona,

is usually scattered rather than in pure stands. The trees attain a

great age and develop very large trunks. With some weathered

dead limbs attached and with dead strips vertically ascending the

trunk and branches, older trees have a grotesque appearance.

Sprouts often are formed at the base of stumps. The wood is used

for fuel and fence posts. Juniper seeds are widely spread by birds

and wild mammals which eat the **berries.'*

ROCKY MOUNTAIN JUNIPER (Juniperus scopulorum Sarg.)

Also called western juniper (lumber), Rocky Mountain redcedar.

Description : Small to medium-sized, scale-leaved evergreen tree

20 to 50 feet tall, with straight trunk up to IV2 i^^t in diameter,

with narrow and pointed open, conical crown, and with slender

branches often drooping at the ends. Leafy twigs slender, about

%2 inch in diameter. Leaves scalelike, Vie inch long, usually gray

green, or on leading shoots needlelike, up to 14 inch long. "Berry"

1/4 inch in diameter, bright blue, covered with a bloom, juicy,

usually 2-seeded, maturing the second year. Bark thin, fibrous and
SOUTHWESTERN TREES 23

shreddy, dark reddish brown or gray. Wood soft, lightweight, deep

red with thick whitish sapwood.

Distribution: Scattered in mountains and canyons of pinyonjuniper woodland and lower part of ponderosa pine forest, 5,000

to 9,000 feet elevation. New Mexico: mountains of northern and

central parts south to White Mountains and Mogollón Mountains.

Arizona: mountains and plateaus of eastern and northern parts,

from White Mountains and Lukachukai Mountains west through

Mogollón Plateau to Coconino Plateau, Grand Canyon, and Kaibab

Plateau. Widely distributed in Rocky Mountain region from New

Mexico north to western North Dakota, west to Montana, Alberta,

and British Columbia, and south to Washington, Nevada, and

Arizona.

Rocky Mountain juniper, a slender tree with grayish green

foliage, is graceful and highly ornamental. The form with drooping

twigs is called "weeping juniper." The trees grow faster than other

southwestern junipers and are planted in shelter belts and as ornamentals. The wood is used for fonce posts, fuel, and lumber and

is suitable for cedar chests.

ONE-SEED JUNII>ER (Jumpvrus morjosperma (Engelm.) Sarg,)

Botanical synonym: J. pymiwcarpa (Lemm.) Cory,

Description: Äluoh-branchod, spreading, often scraggy, scaleleaved evorgroon shrub or small tree 10 to 25 feet tall, with several

curved branches from the gi'ound, usually without a single upright trunk but sometimes with a trunk to V/2 f^et in diameter.

Loafy twigs stout, about M« inch or less in diameter. Leaves scalelike, h(\ inch or more in length, yellow green. Pollen and seeds

borne on diíToront trees (dioecious). "Berry" 14 inch in diameter,

dark blue, covered with a bloom, juicy, 1-seeded, maturing in one

year. Bark iibrous and shreddy, gray. Wood soft, lightweight,

light reddish brown with whitish sapwood.

Distribution : Common and widespread on plains, plateaus, and

foothills in pinyon-juniper woodland, growing with pinyon and

Utah juniper, or sometimes in upper part of desert and desert

grassland, 3,000 to 7,000 feet elevation, widely distributed. New

Mexico : almost throughout. Arizona : widespread but absent from

northeastern, southwestern, and extreme western parts. Western

Texas and extreme western Oklahoma, west to Colorado and

Nevada, and south to Arizona and northern Mexico.

One-seed juniper is the commonest JIUUIHM* in Now Mexico but

not as abundant in Arizona as Utah juniper. I'he wood is much

used for fence posts and fuel.

These two similar species occasionally grow together but can

usually be distinguished by the following differences: Utah juniper

is larger, with a definite trunk, while one-seed juniper is smaller

and usually shrubby, with several branches from the ground. The

former has larger, mealy, 1- or 2-seeded "berries*' borne on the

same trees as the pollen (monoecious), while one-seed juniper has

smaller, juicy, 1-seeded '^berries'* on the female trees and pollen

on male trees (dioecious).
24 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

UTAH JUNIPER {Juniperus osteosperma (Torr.) Little)

Also called western juniper (lumber). Botanical synonyms:

J,tttahensis (Engelm.) hemm.; J. megalocarpaSndv/.

Description : Small, scale-leaved evergreen tree 15 to 40 feet tall,

usually with definite upright trunk 1 to 3 feet or more in diameter,

branching usually several feet above the ground to form a broad,

rounded or conical, open crown. Leafy twigs stout, about Vie inch

or less in diameter. Leaves scalelike, about Vic inch long, yellowgreen. "Berry" 14 to % inch in diameter, brownish, covered with

a bloom, mealy, 1- or 2-seeded. Bark fibrous and shreddy in long

strips, gray. Wood soft, lightweight, light brown with thick

whitish sapwood.

Distribution : Common to abundant on dry plains, plateaus, hills,

and mountains in pinyon-juniper woodland, often in pure stands

or with pinyon, 3,000 to 7,500 feet elevation, widespread in Arizona.

New Mexico : limited to western border from Mogollón Mountains

north to Tunitcha Mountains and Aztec. Arizona: widespread

across central and northern parts from Gila River northward.

Range chiefly in Great Basin region, from western New Mexico

north to southwestern Wyoming, west to southern Idaho and

Nevada, and south to southeastern California and Arizona.

Utah juniper is the commonest juniper in Arizona but in New

Mexico is of restricted occurrence. In various places it occupies

pure stands, especially westward and at elevations below the limits

of pinyon. Within the past 75 years junipers have increased, thickened, and spread onto adjacent short grass and desert grassland

vegetation in the Southwest. This change is considered undesirable on lands used for grazing. The durable wood is valuable for

fence posts and is used also for fuel. The large, mealy "berries" are

eaten by wildlife and formerly also by the Indians.

Common juniper (Junipemts communis L. ; botanical synonym,

/. sibirica Burgsd.), the only other conifer native in New Mexico

and Arizona, is a spreading or nearly prostrate shrub less than 3

feet tall, rarely becoming a small tree in northeastern United States.

The awllike evergreen leaves are in groups of 3, % to V2 inch long,

sharp and prickly, whitish and grooved above, shiny yellow green

beneath. This shrub is scattered in the spruce-fir forest up to the

timber line, 8,000 to 11,500 feet elevation, in higher mountains of

northern New Mexico from Sandia Mountains and Sangre de Cristo

Range westward and in northeastern Arizona from White Mountains and Lukachukai Mountains to Kaibab Plateau. Widely distributed, with varieties, across North America, Europe, and Asia.

Palm Family (Palmae)

CALIFORNIA WASHINGTON!A (Washingfonia filifera (Linden)

H. Wendl.)

Also called California-palm, California washington-palm, desertpalm, California fan-palm. Botanical synonym: W, filamentosa

Kuntze.

Description: Medium-sized to tall evergreen palm tree 20 to 60
SOUTHWESTERN TREES 25

One-seed juniper. Utah juniper. California washingtonia.

feet or more in height, with thick, columnar, unbránched trunk 2

to 3 feet or more in diameter and with rounded crown of erect and

spreading leaves and old dead leaves hanging down against trunk

in a thick thatch. Leafstalks 4 to 6 feet long, stout, with hooked

spines along edges, becoming smaller or entirely absent above.

Leaf blades fanlike, very large, 6 feet or more in diameter, gray

green, the outer part split into many narrow, folded, leathery segments with edges frayed into many threadlike fibers. Flower clusters large and branched, 10 to 12 feet long, drooping, bearing numerous small flowers % inch long, white, slightly fragrant. Berry

nearly i/^ inch long, black, with thin edible flesh and 1 large seed.

Trunk rough and checkered, with vertical cracks more prominent

than the horizontal lines, grayish brown, in upper part covered by

mass of dead leaves. Wood without annual rings, soft and lightweight, yellowish.

Distribution : Rare and local in canyons of desert mountains, in

Arizona only from one locality, Kofa Mountains, about 2,500 feet

elevation, in southwestern part; not in New Mexico. Arizona:

known only from about 100 wild trees in Palm Canyon and other

deep, narrow canyons of Kofa Mountains, about 25 miles southeast

of Quartzsite, Yuma County. Also in southeastern California, such

as Palm Canyon near Palm Springs and Thousand Palms Canyon

near Indio, and in northern Lower California, Mexico.

California washingtonias are commonly planted as ornamentals

in southern Arizona but were not known to be native in the State

until discovered in the Kofa (or S. H.) Mountains in 1923. From

the Quartzsite-Yuma highway about 17 miles south of Quartzsite

a very rocky road or trail extends eastward about 8 miles to the

foot of the mountains. A hike of li/i to 2 miles up Palm Canyon

leads to these beautiful palms.

In southeastern California, where this species is more common,

the fruits were gathered and eaten by Indians. A related species

from Lower California, Mexican washingtonia (W. robusta H.

WendL), distinguished by more slender and taller trunks about 1

foot in diameter above the wider base, is also frequent in cultiva-
26 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

tion. Both species are widely planted in subtropical portions of the

United States and in other parts of the world. Washingtonia is

dedicated to President George Washington (1732-99).

Lily Family (Liliaceae)

SOAPTREE YUCCA (Yucca elata Engelm.)

Also called palmilla, soapweed. Botanical synonym : Y. verdiensis McKelvey.

Description: Narrow-leaved evergreen, palmlike shrub or small

tree, usually 3 to 6 feet tall and infrequently 10 to 15 feet or rarely

25 feet or more in height, with trunk 6 to 9 inches in diameter,

unbranched or with few branches, bearing at the top a cluster of

spreading grasslike leaves. Leaves numerous, very long and narrow, 1 to 21/2 feet long, i/g to % inch wide, leathery and flexible,

yellow green, ending in a sharp spine, with threads along the

edges.^ Flower stalk large, upright in top of plant, 3 to 6 feet or

more in length, much branched in upper half, resembling a candelabra. Flowers numerous in large clusters, II/2 to 2 inches long,

whitish, in late June and early July. Seed capsules cylindrical, dry,

about 2 inches long, light brown, splitting open in 3 parts to release the many thin black seeds and remaining attached through

the winter. Trunk bare in lower part, slightly furrowed and gray,

in upper part covered by old dead leaves. Wood soft and spongy,

lightweight, light brown.

Distribution: Common on sandy plains, mesas, and washes,

desert grassland and desert, often forming pure stands as the only

conspicuous woody species with the grasses, 1,500 to 6,000 feet

elevation, widely distributed. New Mexico: southern part from

Tularosa Basin westward, north in Rio Grande drainage nearly to

Albuquerque and north to Gila River drainage. Arizona: southern

and central parts north to Salt River drainage in Gila County and

Verde River drainage in Yavapai and southern Coconino Counties

and west to Salome (Yuma County). Also in southwestern Texas

and northern Mexico.

Soaptree yucca is very common and conspicuous on large areas

of desert grassland in southern New Mexico, while related, trunkless species are characteristic of the short-grass plains in other

parts of the State. Some very large soaptree yuccas up to 26 feet

or more in height are preserved at Jornada Experimental Range,

maintained by the Forest Service, in northern Dona Ana County,

New Mexico. Yucca is the State flower of New Mexico.

Height growth in soaptree yucca is extremely slow, about 1 inch

a year. Thus the tallest plants are 200 to 300 years old. When the

long, slender or branched trunks lose balance and fall over, they

may continue to grow for a time, but sprouts at their bases eventually replace them.

The name soapweed refers to the soapy material in the roots and

trunks, which has been used as a substitute for soap. The leaves

were employed by the Indians in making baskets and are a possible

emergency source of coarse fiber. In drought periods the chopped
SOUTHWESTERN TREES 27

Soaptree jnicca. Joshua-tree. Schotts yucca.

stems have served as emergency food for cattle. On the ranges

cattle relish the young flower stalks. Indians ate the flowers also.

Small plants can be grown as ornamentals if carefully transplanted

with suflScient roots. This species is planted along highways also.

JOSHUA-TREE (Yucca brevifolia Engelm.)

Also called Joshua-tree yucca. Botanical synonym : Y, brevifolia

var. jaegeriana McKelvey.

Description: Picturesque or grotesque, narrow-leaved evergreen,

small or medium-sized tree 15 to 30 feet (rarely 40 feet or more)

in height, with short stout trunk 1 to 3 feet or more in diameter,

with open broad crown of many stout, widely spreading or sometimes drooping branches forking at intervals of 2 to 3 feet, bearing

at the ends clusters of spreading, grasslike leaves. Leaves many,

long and narrow, 8 to 14 inches long (or as short as 4 inches in a

form), 14 to y2 inch wide, stiff, flattened but keeled on outer surface, smooth or slightly rough, blue-green, ending in a short, sharp

spine, the edges yellowish and bearing many minute sharp teeth.

Flower stalks at ends of branches, 1 to 11/2 feet long, much branched

and bearing flowers nearly to base. Flowers many, crowded in clusters, 11/2 to 21/2 inches long, greenish yellow, with unpleasant odor,

from March to May. Fruit egg-shaped, 21/2 to 4 inches long and

about 2 inches in diameter, green but becoming brovm, fleshy, not

splitting open, falling soon after maturity. Branches and small

trunks covered with dead stiff leaves pressed downward; larger

trunks corky, rough, deeply furrowed and cracked into plates,

brown or gray. Wood lightweight, soft, spongy and pliable, light

brown or whitish.

Distribution: The characteristic tree scattered or in "forests,"

on desert plains in the Mohave desert, 2,000 to 3,500 feet elevation,

in northwestern Arizona; not in New Mexico. Arizona: north-
28 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

western part, in southwestern corner of Yavapai County, northern

border of Yuma County, and southern and western Mohave County.

Also in extreme southwestern corner of Utah, southern Nevada,

and southern California.

Joshua-tree is the outstanding plant of the Mohave desert, which

is located mostly in California and Nevada, and like the saguaro

of southern and central Arizona has become a familiar symbol of

deserts. Ranges of the two monarchs of the desert meet in Arizona at a few places near Bill Williams River in southern Mohave

County. The Mormon pioneers a century ago gave to this species

the name of Joshua, a leader of a desert people pointing the way to

a new Promised Land or perhaps praying with uplifted arms.

These weirdly forking plants appear as if survivors of a primitive

age. They probably are among the oldest living things in the

desert, though not forming annual rings of wood by which age

could be counted. Large trees perhaps are 200 to 300 years old, or

older. A California giant more than 60 feet tall but no longer living

was estimated to be 1,000 years old.

Extensive stands of Joshua-trees are preserved in the Joshua

Tree National Monument of 1,289 square miles in southeastern

California, with headquarters at Twentynine Palms. In Arizona,

one of the most accessible localities is a large "forest*' in southwestern Yavapai County westward along a road about 12 miles

west of Congress Junction, which is on the highway between

Phoenix and Prescott. Part of this area should be preserved as a

State park.

A smaller, more compact form usually only 9 to 12 feet tall and

with shorter leaves mostly 4 inches long is found in the vicinity of

Virgin River valley, Mohave County, in the extreme northwestern

comer of Arizona, and westward in a smaller range than the

typical form.

The spongy, fibrous wood has been used in manufacture of paper,

for surgeons' splints, wrapping material and boxes, and novelties.

However, if harvested extensively, these scattered, slowly growing

desert giants would be decreased greatly in numbers.

SCHOTTS YUCCA (Yucca schottii Engelm.)

Also called mountain yucca, hoary yucca, Spanish bayonet,

Spanish dagger.

Description: Narrow-leaved evergreen shrub or small tree 5 to

18 feet tall, with usually 2 or 3 trunks from base, the trunks unbranched or with 1 or 2 branches, often leaning slightly, bearing

at the top a cluster of spreading bayonetlike leaves. Leaves many,

very long and narrow, 1% to 2^/^ feet or more in length, 1 to 2

inches wide, flat, leathery and flexible, blue-green, ending in a very

short, sharp spine, the edges reddish and without teeth or threads.

Plawer stalk upright, 1 to 21/2 feet long, finely hairy, much

branched and bearing flowers almost to base. Flowers many in

large clusters, 1 to 1^4 inches long, white, from April to August.

Fruit bananalike, 4 to 5 inches long and 1% to 2 inches in diameter,

green, fleshy, not splitting open, falling before winter. Trunk
SOUTHWESTERN TREES 29

Mohave yucca. Torrey yucca. Bigelow nolina.

mostly covered with dead leaves, at base rough and scaly, with

many horizontal leaf scars, reddish brown or gray.

Distribution: Slopes and canyons in oak woodland and rare in

upper desert grassland, extending to a higher elevation than the

other tree yuccas, 4,000 to 7,000 feet elevation, mountains along

the Mexican border. New Mexico: mountains of extreme southwestern corner in southern Hidalgo County. Arizona: mountains

of southeastern part, from Cochise and Greenlee Counties west to

Santa Catalina Mountains in Pima and Final Counties and to Santa

Cruz County. Also in Sonora, Mexico.

Schotts yucca is an attractive ornamental in cultivation. It was

discovered by Arthur C. V. Schott (1814-75), German-American

naturalist, who made large plant collections with the United StatesMexican Boundary Survey in the early 1850's.

MOHAVE YUCCA (Yucca mohavensis Sarg.)

Also called Spanish dagger. Botanical synonym : Y. schidigera

RoezL

Description: Narrow-leaved evergreen shrub or small tree 5 to

16 feet tall and 6 to 10 inches in trunk diameter, usually with few

branches or unbranched, bearing at the top a cluster of widely

spreading daggerlike leaves. Leaves many, very long and narrow,

iy2 to 2 feet (or sometimes 4 feet or more) in length, % to IV2

inches wide, stiff and stout, concave, broadest at the middle,

yellow green, ending in a short, sharp spine, with many coarse

threads along the edges. Flower stalk upright, II/2 to 2^4 feet or

more in length, projecting only slightly beyond the longest leaves,

branched and bearing flowers almost to base. Flowers numerous,

crowded in large clusters, ll^ to 2 inches long, whitish or creamcolored and often purple-tinged, in March and April. Fruit 2 to 3
30 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

inches long and 1 to l^^ inches in diameter, fleshy, sweetish, and

edible, not splitting open, falling before winter. Trunk covered

with dead leaves or sometimes bare at base, furrowed and gray

brown. Wood soft and spongy, lightweight, light brown.

Distribution: Rocky slopes and plains in desert, 1,000 to 3,500

feet elevation, northwestern Arizona ; not in New Mexico. Arizona :

northwestern part in Mohave desert west of Kingman, western

Mohave County. Also in southern Nevada, southern California,

and northern Lower California, Mexico.

TORREY YUCCA (Yucca torreyi Shafer)

Also called palma, Spanish bayonet, Spanish dagger. Botanical

synonyms : F. baccata Torr. var. macrocarpa Torr. ; Y. Tnacrocarpu

(Torr.) Merriam, not Engelm.

Description: Narrow-leaved evergreen shrub or small tree 3 to

16 feet tall, with trunk usually single and usually unbranched, 6

to 8 inches in diameter, bearing at the top a cluster of spreading

daggerlike leaves. Leaves many, very long and narrow, 2 to 3 feet

or more in length, 114 to 2 inches wide, stiff and stout, concave,

yellow green, ending in a short, sharp spine, with many whitish

threads along the edges. Flower stalk upright, 3 to 4 feet, much

branched and bearing flowers nearly to base. Flowers many in

large clusters, large, 3 to 4 inches long, bell-shaped, cream-colored,

in April or March. Fruit bananalike, 4 to 5V^ inches long and ly^

to 2 inches in diameter, fleshy, not splitting open, falling before

winter. Trunk covered with living and dead leaves usually to base,

or scaly and dark brown at base.

Distribution: Scattered on mesas, plains, and foothills in desert

and desert grassland, 3,700 to 5,000 feet elevation, in a limited area

of southeastern New Mexico ; not in Arizona. New Mexico : southeastern part, from Texas boundary north to Carlsbad Caverns National Park in Eddy County and to Guadalupe Mountains and

Tularosa in Otero County ; also north from El Paso, Texas, to Las

Cruces and vicinity in Dona Ana County, New Mexico. Also in

southwestern Texas and Chihuahua, 'Mexico.

Though Torrey yucca is of restricted occurrence, a closely related, trunkless species, datil yucca (Yucca baccata Torr.) is common and widespread over most of New Mexico and Arizona. The

large, fleshy, bananalike fruits of both species are eaten by the

Indians fresh, roasted, or dried, while the leaves were used in

basket making. Torrey yucca is easily transplanted and grown for

ornament and has been used in landscaping along highways. It

honors John Torrey (1796-1873), American botanist and chemist

of Columbia University, who named many new species of plants

from the Southwest.

BIGELOW NOLINA (Nolina bigelovti (Torr.) S. Wats.)

Variety: Parry nolina (Nolina bigelovti var. parryi (S. Wats.)

L. Benson; botanical synonym, N. parryi S. Wats.).

Description: Narrow-leaved evergreen shrub or rarely small

tree 4 to 16 feet tall, resembling yucca, with massive, unbranched
SOUTHWESTERN TREES 31

trunk 2 to 3 feet in diameter, bearing at the top a dense cluster of

stiff, spreading, grasslike leaves and below mostly covered with old

dead leaves. Leaves numerous, very long and narrow, 2 to 4V^ feet

long and % to % inch wide, grasslike, stiff and leathery, with

edges slightly rough (edges saw-toothed in the variety), separating

into long fibers, in age straw-colored and hanging down against

the trunk. Flower stalk upright, large, 3 to 8 feet or more in

length, the upper half or two-thirds much branched and bearing

very many small flowers Vs inch or more in length, white with

greenish tinge, in June and July. Seed capsule about 1/2 inch in

diameter, thin and membranous, 3-winged, with few seeds.

Distribution : Rocky hillsides and canyons in desert, 500 to 3,500

feet elevation ; not in New Mexico. Arizona : western part, in Yuma,

Mohave, and western Yavapai Counties and Grand Canyon, Coconino County. Also in southeastern California and in Baja California and Sonora, Mexico.

The variety Parry nolina, with leaf edges saw-toothed and with

slightly larger flowers and fruits than the typical variety, occurs

in Arizona as a shrub near Kingman and southward in Mohave

County and is the common type in California.

Bigelow nolina is described in manuals as a shrub and until

recent years was not known to reach tree size. However, Leslie

N. Goodding has discovered in Tinajas Altas Mountains of Yuma

County, southwestern Arizona, small trees of this species up to 15

feet in height and 3 feet in trunk diameter. Numbers of these

oddly shaped desert trees with about the same maximum size are

under protection in Joshua Tree National Monument, southeastern

California. The large flower stalks with beautiful white flower

clusters are visible from a distance as landmarks in the desert.

This species is named for John M. Bigelow (1804-78), surgeon and

botanist, who made large plant collections in the Southwest on

Government surveys from 1850 to 1854.

Willow Family (Salicaceae)

NARROWLEAP COTTONWOOD (Populus angustifolia James)

Also called narrowleaf poplar, black cottonwood, mountain cottonwood.

Description: Medium-sized tree to 50 feet in height and V/^

feet in trunk diameter, with narrow crown and slender, erect

branches. Leaves lance-shaped, usually 2 to 3 inches long or up to 6

inches on vigorous shoots, narrow and usually less than 1 inch

wide, tapering and long-pointed, finely saw-toothed, thin but firm,

not hairy, bright yellow-green above, paler beneath. Flowers of

this genus male and female on different trees (dioecious), in long,

narrow catkins, in early spring. Seed capsules in catkins 2^^ to 4

inches long, with many cottony seeds. Bark smooth, light yellowgreen, on large trunks becoming fissured and light gray brown.

Wood lightweight, light brown with whitish sapwood.

Distribution : Common to abundant along streams in mountains,

growing with willows and alders, ponderosa pine forest and pinyon-
32 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

juniper woodland zones, 5,000 to 7,000 feet elevation, widely distributed. New Mexico : mountains of southern, central, and northem parts, from White Mountains, Organ Mountains, Black Range

and Mogollón Mountains northward; also common in San Juan

valley, San Juan County. Arizona: mountains of eastern and

central parts, west to Pima, Yavapai, and Coconino Counties.

Widely distributed in Rocky Mountain region from southwestern

Texas north to Black Hills of South Dakota, Montana, and Alberta,

west to Washington, and south to Nevada and Arizona. Also in

Chihuahua, Mexico.

Narrowleaf cottonwood, easily distinguished by its willowlike

leaves, is planted as a shade tree in many places and is suitable

for erosion control.

Lanceleaf cottonwood (XPopulus acuminata Rydb.), formerly

thought to be a distinct species, is considered by Ernest Rouleau to

be a hybrid of narrowleaf cottonwood with plains cottonwood

(Populus sargenta Dode). This hybrid differs from narrowleaf

cottonwood in its slightly broader, coarsely toothed, ovate leaves

with longer leafstalks. It has been reported from various parts of

New Mexico and Arizona but probably is uncommon in the Southwest and restricted to areas where the two parents meet, such as

northeastern New Mexico. Some trees referred to as lanceleaf cottonwood may represent hybrids of narrowleaf cottonwood with

other species having broad leaves.

QUAKING ASPEN (Populus tremuloides Michx.)

Also called aspen, golden aspen, quaking asp, trembling poplar.

Botanical synonyms: P. tremuloides var. aurea (Tidestr.) Daniels,

P. aurea Tidestr.

Description: Small to medium-sized tree usually less than 40

feet in height and 1 foot in trunk diameter, rarely 80 feet tall and

2% feet in diameter, with slender, rounded crown of thin foliage.

Leafstalks 114 to 3 inches long, slender, and flattened. Leaf blades

nearly round, ll^ to 3 inches long, short-pointed, rounded at base,

finely saw-toothed, shiny green above, dull green beneath, turning

golden or orange in autumn before falling. Seed capsules in catkins, with many cottony seeds. Bark smooth, thin, whitish or

yellowish, on very large trunks becoming thick, furrowed, and dark

gray. Wood soft and brittle, lightweight, light brown with very

thick whitish sapwood.

Distribution : Common and widely distributed in upper part of

ponderosa pine forest, Douglas-ñr forest, and spruce-fir forest in

high mountains and plateaus, on cool, shaded mountain slopes, in

canyons, and along streams, often forming pure stands or groves,

6,500 to 10,000 feet elevation. New Mexico: western two-thirds, on

all the higher mountains. Arizona: high mountains and plateaus

in northeastern half, from Chiricahua Mountains west to Pima and

Mohave Counties and Kaibab Plateau. Range very broad, one of

the most extensive of all native North American trees, from

Labrador across Canada to Alaska, in northeastern United States

south to West Virginia and Missouri, and south in Rocky Moun-
SOUTHWESTERN TREES 33

Narrowleaf

cottonwood.

Quaking aspen. Fremont cottonwood. Rio Grande

cottonwood.

tains and mountains of Pacific coast region to California, Arizona,

southwestern Texas, and northern Mexico.

Quaking aspen is so named because the slender, flattened leafstalks enable the leaves to tremble in the slightest breeze. The soft

smooth whitish bark, which is favored by persons carving initials

on trees, makes identification easy. The form in western United

States, characterized largely by the deeper, golden color of autumn

foliage, is considered by some botanists as varietally distinct.

Aspens are pioneer trees on burned areas, forming thickets of

short-lived trees afterwards replaced by conifers. Propagation is

chiefly from root sprouts. The wood has been used in the Southwest in manufacture of excelsior and elsewhere also for pulpwood,

boxes and crates, food containers, and matches. Domestic livestock

and deer browse the foliage within reach.

FREMONT COTTONWOOD (Populus fremontii S, Wats.)

Also called Fremont poplar, alamo.

Description: Large tree 50 to 100 feet tall, with trunk 2 to 4 feet

or more in diameter, often leaning, and with broad, flat, open crown

of large branches. Leafstalks long slender, flattened. Leaf blades

broadly triangular, 2 to 2% inches long and 2^/4 to 3 inches wide,

short-pointed, nearly straight across base, coarsely and irregularly

saw-toothed, thick and leathery, usually not hairy, shiny yellow

green, turning yellow in autumn. Seed capsules in catkins 4 to 5

inches long, with the stalks less than i/4 inch long, the egg-shaped

capsules 14 to % inch long, with many cottony seeds. Bark gray

or brown, thick, rough and deeply furrowed. Wood light brown

with whitish sapwood, soft, lightweight, brittle.

Distribution : Common along streams and in moist soils of desert,

desert grassland, and woodland zones, often associated with Arizona sycamore, willows, and alders, 150 to 6,000 feet elevation.

New Mexico : southwestern part, in Gila River drainage. Arizona :

along streams almost throughout, except in northeastern part and

at high elevations. Southwestern New Mexico northwest to southwestern Utah, Nevada, and California, south to Arizona and northern Mexico.
34 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

This species, the cottonwood of the desert zone in Arizona, is

planted extensively as a shade tree and along irrigation ditches.

Like other cottonwoods, it is easily propagated from cuttings and

rapidly growing but short-lived. The wood is used as fuel and for

temporary fence posts but is not durable. Fremont cottonwood is

common at Grand Canyon, where it is the only large tree in the

lower depths and where its green coloring is visible to visitors on

the rims above.

RIO GRANDE COTTONWOOD (Populus wislizeni (S. Wats.)

Sarg.)

Also called Wislizenus cottonwood, valley cottonwood, Rio

Grande poplar, alamo. Botanical synonym : P. fremontii S. Wats,

var. wisUzeni S. Wats.

Description: Large tree 40 to 100 feet tall and 2 to 4 feet or

more in trunk diameter, with flat, widely spreading crown of large

branches. Leafstalks long, slender, flattened. Leaf blades broadly

triangular, 2 to 2V2 inches long and about 3 inches wide or sometimes larger, abruptly short-pointed, straight across base, coarsely

and irregularly saw-toothed, thick and leathery, shiny yellow green,

turning yellow in autumn. Seed capsules in catkins 31/2 to 5 inches

long, the long stalks 1/2 to % inch long and longer than the narrow

capsules, with many cottony seeds. Bark thick, deeply furrowed

into broad flat ridges, light gray. Wood soft, lightweight, brittle,

yellowish brown with whitish sapwood.

Distribution : Common along the larger streams in desert, desert

grassland, and woodland zones, 3,800 to 6,000 feet elevation; not

in Arizona. New Mexico : western half, from Tularosa Basin north

and west, chiefly in Rio Grande drainage northward across the

State and in San Juan drainage in northwestern corner, forming

extensive woodlands or *'bosques'' on the broad, sandy flood plains

of these two rivers. From southwestern Texas northwest across

New Mexico to Colorado and in northern Mexico.

Rio Grande cottonwood, as its name suggests, is the **valley

cottonwood" of New Mexico and one of the most common shade

trees in the State and is widely planted along irrigation ditches.

The wood is used for fuel, temporary fence posts, and rafters of

buildings.

PLAINS COTTONWOOD (Populus sargentn Dode)

Also called plains poplar.

Description : Large tree 60 feet or more in height and 2 to 4 feet

or more in trunk diameter, with broad open crown of large

branches. Leafstalks long, slender, flattened. Leaf blades ovate,

3 to 4 inches long and broad, long-pointed, coarsely saw-toothed

with curved teeth, light green, shiny. Seed capsules in catkins 4 to

8 inches long, very short-stalked, with many cottony seeds. Bark

thick, deeply furrowed into broad flat ridges, light gray. Wood

soft, lightweight, brown with whitish sapwood.

Distribution : Along streams in short grass plains, 4,000 to 6,000

feet elevation ; not in Arizona. New Mexico : plains in northeastern
SOUTHWESTERN TREES 35

Plains cottonwood. Pacific willow. Whiplash willow. Red willow.

part. Great Plains region, from northwestern Texas north to central Kansas, North Dakota, and Saskatchewan, west to Alberta and

Montana, and south to eastern Colorado and northeastern New

Mexico.

PACIFIC WILLOW {Salix lastandra Benth.)

Also called western Vjlack willow, yellow willow.

Description: Shrub or small tree, rarely to 40 feet or more in

height. Twigs relatively stout, purple or reddish brown or in early

spring bright yellow, hairy when young but becoming hairless and

shiny. Leaves lance-shaped, 2 to 5 inches long and 14 to 1 inch

wide, long-pointed, mostly rounded at base, edges ñnely sawtoothed with yellowish gland-tipped teeth, thick and slightly

leathery, dark green and very shiny above, paler or whitish beneath, hairless. Flowers of this and other willows male and female

on different trees (dioecious), in long, narrow, upright, greenish catkins, in early spring. Catkins on leafy stalks, 2 to 4 inches long at

maturity. Seed capsules hairless, with many cottony seeds. Bark

fissured, dark brown. Wood brittle, pale brown.

Distribution: Shrubby willow forming clumps along mountain

streams in ponderosa pine forest, 5,000 to 7,500 feet elevation.

New Mexico : common in mountains of western and northern parts

from Mogollón Mountains northward to Sangre de Cristo Range.

Arizona: eastern part in White Mountains and Tonto Basin (Gila

County). New Mexico north to Wyoming, Saskatchewan, Yukon,

and Alaska, and south to southern California and Arizona.

Whiplash willow {Salix caudata (Nutt.) Heller var. bryantiana

Ball & Bracelin) is related to Pacific willow, but this variety is distinguished by the bright yellow or orange twigs always hairless

and by the very long-pointed, lance-shaped leaves green on both

sides. It is a tall bushy shrub which may not reach tree size in the

Southwest, where it apparently is uncommon in ponderosa pine

forest of northern New Mexico south to Santa Fe. Reported from

eastern Arizona at Springerville (Apache County). This species

is distributed from New Mexico north to southern Alberta, west to

southern British Columbia, and south to California and Arizona.
36 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

RED WILLOW {Salix laevigata Bebb)

Also called polished willow.

Description : Small or medium-sized tree to 40 feet in height and

2 feet in trunk diameter. Twigs yellow to reddish brown. Leaves

lance-shaped or oblong lance-shaped, 2 to 6 inches long and %

to ly^ inches wide, short-pointed, edges slightly turned under and

obscurely saw-toothed, without hairs at maturity, dark green and

shiny above, paler beneath. Catkins 2 to 4 inches long on leafy

twigs in March. Seed capsules long-stalked, hairless with many cottony seeds. Bark furrowed into irregular scaly ridges, dark brown.

Wood soft, lightweight, brittle, light reddish brown with whitish

sapwood.

Distribution: Uncommon along streams in oak woodland and

pinyon-juniper woodland and sometimes desert zone, 1,800 to 5,000

feet elevation; not in New Mexico. Arizona: scattered over the

State from Huachuca Mountains and Final Mountains northwest

to Prescott, Grand Canyon, and Beaver Dam in northwestern

Mohave County. Arizona and southern Utah, west to northern

California, and south to Lower California, Mexico.

BONPLAND WILLOW {Salix bonplandiana H. B. K.)

Also called Toumey willow. Botanical synonym : S. bonplandiana

var. toumeyi (Britton) Schneid.

Description : Small or medium-sized tree 20 to 50 feet in height

and 1 to 3 feet in trunk diameter, with broad, rounded crown. Twigs

slender, red or purple, hairless. Leaves narrowly lance-shaped, 4 to

6 inches long and 1/2 to % inch wide, long-pointed, broadest near

middle and tapering to base, edges inconspicuously fine-toothed or

without teeth, green and shiny above, whitish beneath, without

hairs at maturity, shedding irregularly in winter. Catkins leafystalked, about 11/2 inches long. Seed capsules reddish yellow, hairless, with many cottony seeds. Bark rough and fissured or checkered, dark gray or nearly black.

Distribution: Along streams in upper desert, desert grassland,

and oak woodland, 2,500 to 5,000 feet elevation, chiefly near Mexican border. New Mexico : extreme southwestern corner, in southern Hidalgo County. Arizona : common in southeastern and central

parts, from Cochise and Greenlee Counties west and northwest to

Santa Cruz, Pima, Gila, and Yavapai Counties. Also south through

Mexico to Guatemala.

Bonpland willow is one of the common tree willows in southeastern Arizona. It was named for Aimée Bonpland (1773-1858), of

France and afterwards South America, who made large botanical

collections on an expedition with Alexander von Humboldt from

1799 to 1804 to various Spanish colonies in the New World.

GOODDING WILLOW (Salix gooddingi Ball)

Also called Dudley willow, western black willow. Botanical

synonym: S. nigra Marsh, var. vallicola Dudley.

Description : Medium-sized tree 20 to 50 feet in height and 2 to 3

feet in trunk diameter, with broad rounded crown. Twigs yellowish,
SOUTHWESTERN TREES 37

Bonpland willow. Goodding willow. Peachleaf willow. Wright willow.

often slightly hairy. Leaves narrowly lance-shaped and often

slightly curved, 2 to 4 (to 6) inches long and 14 to % inches wide,

long-pointed, broadest at base, finely saw-toothed, green or yellowish green on both sides, usually hairless at maturity. Catkins 2 to

Sy^ inches long on leafy twigs, in March. Seed capsules not

crowded, usually hairless, with many cottony seeds. Bark thick,

rough, deeply furrowed with narrow ridges, gray.

Distribution : Common along streams in the desert, desert grassland, and oak woodland, 150 to 5,000 feet elevation. New Mexico:

southern part, from Eddy and Chaves Counties westward, north

along Rio Grande drainage to Bernalillo in central part and in Gila

River drainage. Arizona : widely distributed, especially in southern

and central parts and along Colorado River to Grand Canyon in

northern part; forming dense forests with Fremont cottonwood on

flood plains of lower Colorado and Gila Rivers in southwestern

part. West central Texas northwest across New Mexico and Arizona to southern Utah, southern Nevada, and northern California,

and south to northern Mexico.

Goodding willow, the largest willow in Arizona, is important for

stream-bank protection because of its deep root system. It honors

Leslie N. Goodding, botanist of the United States Department of

Agriculture, who has made extensive plant collections and many

interesting botanical discoveries in the Southwest.

PEACHLEAF WILLOW (Salix amygdaloides Anderss.)

Also called peach willow, almond willow. Variety : Wright willow {S. amygdaloides var. wrightii (Anderss.) Schneid. ; also called

Wright peachleaf willow, southwestern peach willow; botanical

synonym, S. wrightii Anderss.).

Description : Small tree to 30 feet tall and 1 foot or more in trunk

diameter, with spreading crown. Twigs slender, often slightly

drooping at tip, yellowish or older twigs gray, hairless. Leaves

lance-shaped, 2 to 4 (to ly^) inches long and % to ll^ (to 1%)

inches wide, long-pointed at apex, short-pointed or rounded at base,

hairless at maturity, yellow green above but whitish to white beneath ; leaves in the varietyWright willow (var. wrightii) very narrowly lance-shaped, 2l^ to 3 (to 4) inches long and less than ^/^ inch
38 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

(rarely 1/2 inch) wide, long-pointed at apex and sharply shortpointed at base. Catkins 2 to 3 inches long on leafy twigs. Seed

capsules long-stalked, hairless, with many cottony seeds. Bark

rough and furrowed, gray or brown.

Distribution: Along streams in short grass, desert, desert grassland, and pinyon-juniper woodland, 3,000 to 7,000 feet elevation.

New Mexico : the typical form is common in northern half, extending down Pecos River and Rio Grande drainages to southern border ;

the variety Wright willow in Curry County on eastern border and

on Rio Grande drainage in Dona Ana County at southern border.

Arizona: apparently rare in eastern part, the typical form collected

in Tunitcha Mountains (Apache County) and Rincón Mountains

(Pima County). Peachleaf willow, including the variety, is widely

distributed from southeastern Quebec and New York, west to

southeastern British Columbia and Washington, and south to Arizona, western Texas, and northern Mexico. Wright willow is restricted to western and southwestern Texas, New Mexico, and adjacent northern Mexico.

Wright willow (Salix amygddloides var. wrightii (Anderss.)

Schneid.) is a doubtfully distinct southwestern variety of peachleaf willow, differing from the widespread typical form in its narrower leaves with bases sharply short-pointed (rather than rounded

in part) and in slightly shorter leafstalks.

COYOTE WILLOW (Salix exigua Nuit.)

Also called sandbar willow, acequia willow, basket willow. Includes two southwestern varieties: S. exigim var, stenophylla

(Rydb.) Schneid, and S. exigua var. nevadensis (S. Wats.)

Schneid.

Description: Usually a shrub 6 to 15 feet tall with clustered

stems or rarely treelike, forming thickets. Twigs yellowish and

more or less silvery- or gray-hairy. Leaves almost stalkless, very

narrow, linear or narrowly lance-shaped, li/^ to 3 (or 4) inches

long and % to ^A (or %) inch wide, short-pointed at both ends,

without teeth or with few minute teeth, densely silvery-hairy or

silky on both sides (var. stenophylla), or silvery-hairy while unfolding but soon becoming nearly hairless and yellow green^ (var.

nevadensis), or gray-green and more or less densely gray-hairy on

both sides (typical form). Catkins on leafy twigs, 1 to 2 inches

long. Seed capsules hairless or nearly so, with many cottony seeds.

Bark smooth or becoming rough and fissured at base of large

trunks, gray. Wood soft, lightweight, light brown.

Distribution : Common in moist sandy soil along streams in the

desert, desert grassland, pinyon-juniper and oak woodlands, and

lower ponderosa pine forest, forming dense thickets on sand bars,

shores, and washes, from slightly above sea level to 7,000 feet

elevation, widely distributed. New Mexico: lower mountains nearly

throughout western two-thirds but absent from plains of eastern

part; abundant along Rio Grande. Arizona: almost throughout.

This species with its varieties is widely distributed in the Rocky

Mountain, Great Basin, and desert regions of the West, from
SOUTHWESTERN TREES 39

Coyote willow. Yewleaf willow. Yellow willow. Arroyo willow.

southwestern Texas north to South Dakota and Alberta, v/est to

British Columbia, and south to California, Arizona, and Mexico.

Coyote willow is the common, thicket-forming shrubby willow

in the Southwest. In New Mexico and Arizona the characteristic

variety of this very widespread and variable species has silveryhairy leaves and twigs (vsLT. stenophylla). The variety with yellowgreen leaves nearly hairless at maturity (var. nevadensis) is found

in northern New Mexico and nearly throughout Arizona, w^hile

the typical form with less narrow gray-hairy leaves to % inch or

more in width is rare in this region and more common northward.

This species is drought-resistant and especially suitable for

planting on stream bottoms to prevent surface erosion. The foliage

is excellent browse. The twigs and bark have been used in basket

making by Indians and others, as the local name basket willow

suggests. However, this is not one of the important basket willows

of commerce.

Sandbar willow (Salix interior- Rowlee), a closely related species,

is represented by a shrubby variety (var. angustissima (Anderss.)

Dayton) at the southeastern border of New Mexico. This variety

is distinguished from coyote willow by the narrow leaves with

edges sharply fine-toothed, silvery-silky on both sides when young

but becoming nearly hairless except for hairs remaining on midrib

beneath. This widely ranging species extends from Virginia and

southern Canada west to Alaska and south in Great Plains to

Texas and adjacent Mexico.

YEWLEAF WILLOW (Salix taxifolia H. B. K.)

Also called yew willow.

Description: Large shrub or small to medium-sized tree 20 to

40 feet tall, with a trunk up to 2 feet in diameter and with a dense,

compact, rounded crown. Twigs much branched, slender, densely

white- or silvery-hairy the first year, afterwards gray. Leaves

very small and densely crowded, very narrow, yewlike, almost

stalkless, 1/2 to 1^4 inches long and about V^ inch wide, shortpointed, the edges usually without teeth, densely silvery-hairy

when young and becoming gray-hairy. Catkins at the end of
40 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

short leafy twigs, very short, about 1/2 inch long, in March and

sometimes again in autumn. Seed capsules stalkless, hairy, with

many cottony seeds. Bark rough and fissured, light gray-brown.

Distribution : Infrequent along streams and washes in foothills

and mountains, oak woodland and rarely in desert and desert grassland, 3,500 to 6,000 feet elevation, limited to Mexican border region.

New Mexico: extreme southwestern corner, in southern Hidalgo

County. Arizona: southeastern part, in Cochise, Santa Cruz, and

eastern Pima Counties. Also in southwestern Texas and in Mexico.

Yewleaf willow is a good soil binder, fairly drought-resistant,

and excellent browse for livestock but grows slowly. It should

make an attractive ornamental.

YELLOW WILLOW {Salix lutea Null.)

Description : Usually a shrub with clustered stems and perhaps

not a tree in the Southwest. Twigs yellow and hairless. Leaves

lance-shaped or broadly so, 1 to 3 inches long, short-pointed,

rounded at base, edges finely saw-toothed, thin, generally light

green above, paler and whitish beneath, hairless or nearly so.

Catkins almost stalkless. Seed capsules hairless, with many cottony seeds.

Distribution: Uncommon along mountain streams in woodland

and ponderosa pine forest, 3,800 to 6,500 feet elevation. New

Mexico: White Mountains and northern part of State. Arizona:

northeastern part from Apache County to Coconino and Yavapai

Counties. New Mexico north to Saskatchewan, west to British

Columbia and south to California and Arizona.

Strapleaf willow (Salix ligvlifolia (Ball) Ball; botanical

synonym, S. lutea var. ligtdifolia Ball), a shrub with clustered

stems 3 to 10 feet tall is related to yellow willow and more common

in the Southwest. From the latter, strapleaf willow is distinguished

by the twigs brown to dark brown and often more or less hairy

and by the narrower, strap-shaped or narrowly lance-shaped leaves

2 to 4 inches long, dark green above. It is distributed in the ponderosa pine forest at elevations of 5,000 to 7,000 feet, in New

Mexico in mountains of northeast comer and western two-thirds

south to White Mountains and Mogollón Mountains and in eastern

Arizona west to Flagstaff. Also from New Mexico north to Black

Hills and Wyoming and west to California.

ARROYO WILLOW (Salix lasiolepis Benth.)

Also called white willow.

Description: Usually a shrub with clustered stems but sometimes a small tree to 30 feet in height, with slender erect branches

forming a narrow, irregular crown. Twigs yellow to brown, finely

hairy when young. Leaves very narrow, linear to narrowly oblanceolate, 2^4 to 4 (to 6) inches long and % to % inch wide, shortpointed, edges without teeth or slightly wavy with a few inconspicuous teeth, thick and leathery, dark green above, beneath paler

or whitish, becoming nearly hairless. Catkins almost stalkless,

about 2V2 inches long, densely hairy, in March. Seed capsules
SOUTHWESTERN TREES 41

crowded, dark green, hairless, with many cottony seeds. Bark

smooth, gray brown, on larger trunks becoming rough, fissured

into broad ridges, and darker. Wood soft, lightweight, brittle,

light brown with thick whitish sapwood.

Distribution: Along streams in mountains often with Arizona

alder and Arizona sycamore, 6,000 to 7,500 feet elevation. New

Mexico: mountains of southwestern part from Organ Mountains

to Mogollón Mountains. Arizona : mountains of eastern part from

Cochise and Pima Counties to Apache and Coconino Counties.

Southwestern Texas to Arizona, north to Idaho and Washington,

and south to California. Also in northern Mexico.

SCOULER WILLOW {Salix scouleriana Barrait)

Also called mountain willow, black willow, fire willow.

Description : Large shrub or rarely a small tree to 4 inches in

trunk diameter, with compact rounded crown. Twigs stoutish,

yellow and densely hairy when young. Leaves obovate or elliptical,

11/2 to 4 inches long and i/^ to I14 inches wide, rounded or shortpointed at apex, tapering toward base, edges without teeth or

slightly wavy, thick and firm, yellow-green and nearly hairless

above, beneath whitish and more or less white- or gray-hairy or

furry, or becoming rusty hairy in age. Catkins stalkless or nearly

so, at maturity 1 to 2 inches long, stout and dense. Seed capsules

long, slender, gray-woolly, with many cottony seeds. Bark thin,

divided into broad flat ridges, dark brown. Wood soft, lightweight,

light brown tinged with red and with thick whitish sapwood.

Distribution : Local and uncommon along streams in high mountains, ponderosa pine and Douglas-fir forests, 8,000 to 10,000 feet

elevation. New Mexico : high mountains of western two-thirds and

northeast corner, from Sacramento Mountains, Black Range, and

Mogollón Mountains northward. Arizona : known from Santa Catalina, White, Lukachukai, and San Francisco Mountains and Grand

Canyon. Widely distributed in western North America, especially

in mountains, from New Mexico north to Black Hills, Montana,

Saskatchewan, Yukon, and Alaska, and south to California and

Arizona.

Scouler willow is called fire willow because it rapidly occupies

burned areas in the forests. Unlike most willows, it can grow in

the shade of larger trees. This is an important browse species for

sheep and cattle where suflficiently common. In the Pacific States

it has been planted occasionally for shade and ornament. Scouler

willow is named for its discoverer, John Scouler (1804-71), Scotch

naturalist who made a voyage to northwestern America in 1825.

BEBB WILLOW {Salix hehhiana Sarg.)

Also called beaked willow. Botanical synonym : 5. rostrata Richards., not Thuill.

Description: Usually a much-branched shrub or a small bushy

tree to 15 feet in height, forming clumps or growing singly. Twigs

slender, branching at wide angles, yellowish to brown, gray-hairy

when young but afterward hairless. Leaves elliptical, oblong, or

reverse lance-shaped, usually small, 1 to 3V-2 inches long and % to
42 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

1 inch wide, pointed at both ends or broad at base, edges without

teeth or somewhat wavy, thick and firm, dull green above, whitish

and roughly net-veined beneath, more or less whitish hairy on both

sides but becoming less hairy with age. Catkins on short leafy

twigs, at maturity 1 to 3 inches long and loose. Seed capsules

long-stalked, long, very slender, and hairy, with many cottony

seeds. Bark thin and slightly fissured, reddish. Wood lightweight,

brittle.

Distribution: Moist soils, chiefly along mountain streams in

ponderosa pine, Douglas-fir, and spruce-fir forests, 8,500 to 11,000

feet elevation. New Mexico : high mountains of western two-thirds

and northeast corner, from White and Mogollón Mountains northward. Arizona : high mountains and plateaus of eastern and northern parts, from White Mountains northwest to San Francisco

Mountain and Grand Canyon. Widely distributed from Newfoundland and Labrador across Canada to Alaska, south in mountains

of western United States to California, Arizona, and New Mexico

and south in northeastern States to Nebraska and New Jersey.

Bebb willow has been suggested for stream planting at high

altitudes. In other regions, where the trees become larger, the

wood has been used for baseball bats, charcoal, and gunpowder.

The twigs have been employed in making furniture and baskets.

This species honors Michael S. Bebb (1833-95), American specialist on willows.

Walnut Family (Juglandaceae)

LITTLE WALNUT (Juglans microcarpa Berland.)

Also called Texas black walnut, nogal. Botanical synonym: /,

rupestris Engelm.

Description : Large branching shrub or small tree 10 to 20 feet

tall and 1/2 to li/^ feet in trunk diameter, usually branching at or

near ground, with broad rounded crown. Twigs reddish brown,

densely hairy when young, becoming ashy gray. Leaves pinnately

compound, 8 to 13 inches long, with characteristic walnut odor.

Leaflets usually 17 to 23 (sometimes as few as 13), narrowly

lance-shaped, 2 to 3 inches long and about Yi inch wide, longpointed, usually slightly curved, edges finely saw-toothed or almost

without teeth, thin, becoming hairless or nearly so, yellow green.

Flowers of this and the next species greenish, male in narrow

hanging clusters and female few together, in spring. Walnut fruit

spherical, 1/2 to % inch in diameter, with thin, hairy, brown husk,

thick hard shell, and small edible kernel. Wood hard, heavy, chocolate brown with thick whitish sapwood.

Distribution: Scattered along streams in plains and foothills

desert zone, 3,000 to 4,000 feet elevation; not in Arizona. New

Mexico: southeastern part, common along Pecos River and tributaries west to Guadalupe and Sacramento Mountains. Southern

and western Texas to western Oklahoma, southeastern New Mexico,

and northern Mexico.

This species has the smallest nuts of all the walnuts, suggesting

marbles in size.
SOUTHWESTERN TREES 43

Scouler willow. Bebb willow. Little walnut. Arizona walnut.

ARIZONA WALNUT (Juglans major (Torr.) Heller)

Also called Arizona black walnut, nogal. Botanical synonym : /.

rupestris Engelm. var. ynajor Torr.

Description: Small to medium-sized tree 30 to 50 feet tall and

1 to 2 feet (rarely 4 feet) in trunk diameter, with rounded crown

of widely spreading branches. Twigs reddish brown, densely hairy

when young, becoming ashy gray. Leaves pinnately compound, 7

to 14 inches long, with characteristic strong walnut odor. Leaflets

usually 9 to 13 (rarely to 19), lance-shaped or broadly lance-shaped,

2 to 4 inches long and i/4 to II/2 inches wide, long-pointed, often

slightly curved, edges coarsely saw-toothed, thin, scurfy-hairy

when young but becoming hairless or nearly so, yellow green.

Walnut fruit almost spherical, 1 to IV2 inches in diameter, with

thin, densely hairy, brown husk, thick hard shell, and small edible

kernel. Bark on small trunks smoothish and fissured, on large

trunks thick, deeply furrowed and ridged, grayish brown. Wood

hard, heavy, chocolate brown with thick whitish sapwood.

Distribution: Scattered along streams and canyons, mostly in

mountains, in upper part of desert, desert grassland, and oak woodland zones, often with Fremont cottonwood, Arizona sycamore,

Arizona alder, and willows, 3,500 to 7,000 feet elevation. New

Mexico : mountains of southwestern quarter from Black Range and

Magdalena Mountains westward. Arizona: widely distributed in

mountains of southeastern and central parts west to Baboquivari

Mountains and northwest below Mogollón Rim to southern Coconino

County, Yavapai County, and Hualpai Mountains ; Havasu Canyon

at Grand Canyon. Also in northern Mexico.

The small, thick-shelled walnuts, known in Spanish as nogales,

are often gathered and eaten by the local residents. The trees are

planted for shade. Enlarged burls and stumps at the base of some

tree trunks are prized for the beautiful patterns of their wood and

are manufactured into table tops and veneer. The wood is suitable

for the same uses as black walnut, such as furniture, cabinets, and

gunstocks, and has been cut in small quantities for cabinetmaking.

However, the supply is limited, scattered, and not easily accessible,

and the trees generally are small. The wood is durable and is used

locally for fence posts.
44 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Birch Family (Betulaceae)

KNOWLTON HOPHORNBEAM (Ostrya knowltoni Cov.)

Also called western hophornbeam. Botanical synonym: O.

baüeyi Rose (also called Bailey hophornbeam).

Description: Shrub or small slender tree 10 to 40 feet tall and

6 inches in trunk diameter. Young twigs brown, hairy and with

glandular hairs. Leaves elliptic to ovate, 1 to 21/2 inches long,

short-pointed or rounded at apex, usually rounded or slightly heartshaped at base, edges sharply and doubly saw-toothed, dark yellow

green and slightly hairy above, paler and soft hairy beneath. Male

and female flowers in catkins in April. Fruit conelike, 1 to IV2

inches long and % inch broad, of baglike, papery bracts, each enclosing a nutlet i/i inch long. Bark thin, fissured and peeling off in

long flakes, gray. Wood hard, light reddish brown.

Distribution : Very local in moist canyons, oak woodland, pinyonjuniper woodland, and lower ponderosa pine forest zones, 4,200 to

7,000 feet elevation. New Mexico : known only from Guadalupe and

Sacramento Mountains in southeastern part. Arizona : known only

from Coconino County in northern part at Oak Creek Canyon and

at Grand Canyon, where it is common below both rims. Also in

southwestern Texas and southeastern Utah.

As the common name suggests, the bladdery fruit resembles that

of hops. Knowlton hophornbeam is the only representative of its

genus in western United States but another species, eastern hophornbeam {Ostrya virginiana (Mill.) K. Koch), is widely distributed in the eastern half of the country. The plants of southeastern New Mexico and adjacent Texas are slightly intermediate

between the eastern and western species and have been considered

also as distinct. Frank H. Knowlton (1869-1926), American botanist and paleobotanist of the United States Geological Survey, discovered this species at Grand Canyon in 1889.

WATER BIRCH (Betula occidentalis Hook.)

Also called red birch, black birch. Botanical synonym: B. fontinalis Sarg.

Description : Small tree or large shrub to 25 feet in height and

8 inches in trunk diameter, with finely branched, spreading, open

crown. Twigs often drooping, slender, covered with resinous

glands, light green when young but becoming dark red brown.

Leaves ovate, 1 to 2 inches long, short- or long-pointed, usually

rounded at base, sharply and often doubly saw-toothed, thin, dark

green above, beneath pale yellow green and shiny and covered with

resin dots. Male and female flowers in catkins in early spring.

Fruit of erect or hanging cylindrical cones 1 to 1^4 inches long and

^2 thick, slightly hairy, with many small winged nutlets. Bark

smooth, shiny, copper colored, with conspicuous pale brown horizontal lines (lenticels). Wood soft, light brown.

Distribution : Along streams in mountains, often forming thickets, pinyon-juniper woodland and ponderosa pine forest zones, 5,000

to 8,000 feet elevation. New Mexico: mountains of northwestern
SOUTHWESTERN TREES 45

Knowlton hophornbeam. Water birch, Thinleaf alder. Arizona alder.

part. Arizona : northeastern part, from Lukachukai and Tunitcha

Mountains (Apache County) west to Kaibab Plateau. New Mexico

north to Black Hills and Saskatchewan, west to British Columbia,

and south to northern California and Arizona.

Water birch is the only native birch in the Southwest.

THINLEAF ALDER (Alnus tenuifolia Nuit.)

Also called mountain alder.

Description: Large shrub or small tree to 30 feet tall, with

usually several trunks up to 6 inches or more in diameter spreading from the base, and with rounded crown. Leaves ovate or

oblong, 2 to 4 inches long, short-pointed at apex, rounded, straight,

or slightly heart-shaped at base, edges doubly saw-toothed and

slightly lobed, thin, dark green and hairless above, beneath pale

yellow green and hairless or slightly hairy. Male and female

flowers in catkins in early spring. Fruit of cones % to i/2 inch

long, with hard black scales and many small nutlets, remaining on

tree in winter. Bark on small trunks, thin and grayish but becoming scaly and reddish brown. Wood light brown.

Distribution : Along streams and canyons mostly in mountains,

often forming thickets on stream banks, ponderosa pine forest,

7,000 to 9,000 feet elevation. New Mexico : mountains across northern part of State. Arizona : uncommon in eastern part in Pinaleno,

White, and Tunitcha Mountains and Clear Creek Canyon (Coconino

County). Widely distributed in western North America from New

Mexico north to Saskatchewan, Yukon, and Alaska, south to

southern California, Arizona, and northern Mexico.

The Navajos made a red dye for wool from the powdered bark

of this species, together with ashes of one-seed juniper and a

decoction of mountain-mahogany.

ARIZONA ALDER {Alnus oblongifolia Torr.)

Also called New Mexican alder.

Description: Medium-sized to large tree to 60 or 80 feet in

height, with tall straight trunk 2 to 3 feet in diameter, and with

open, rounded crown. Leaves elliptic, 2 to 3 inches long, short-
46 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

pointed at apex, gradually narrowed at base, edges sharply and

usually doubly saw-toothed, thin, dark green and almost hairless

above, beneath paler and slightly hairy. Male and female flowers

in catkins in March. Fruit of cones about Vg inch long, with hard,

black scales and many small nutlets, remaining on tree in winter.

Bark smooth, thin, dark gray, on large trunks fissured and scaly.

Wood soft, lightweight, whitish when cut but turning to light reddish brown.

Distribution : Along canyons and streams mostly in mountains,

oak woodland and ponderosa pine forest, 4,500 to 7,500 feet elevation. New Mexico: mountains of southwestern part from Black

Range and Magdalena Mountains west to Mogollón Mountains. Arizona : common and widely distributed in mountains of southeastern

and central parts west to Pima County and northwest to Oak Creek

Canyon in Coconino County. Also in northern Mexico.

Beech Family (Fagaceae)

NETLEAF OAK (Quercus reticulata Humb. & Bonpl.)

Botanical synonym : Q, diversicolor Trel.

Description: Small to medium-sized evergreen tree to 40 feet

tall, with broad rounded crown, or a shrub as low as 6 feet in height.

Leaves broadly obovate, varying in form and size, 1 to 4 inches

long, rounded at apex and slightly heart-shaped at base, edges with

several small spiny teeth especially toward apex, thick and stiff,

above dark green and slightly hairy and with veins sunken, beneath paler and yellow hairy and with a network of raised veins.

Flowers of this and other oaks male in narrow hanging clusters

and female 1 or few in leaf axils, in spring. Acorns 2 or 3 together

on long stalk 1 to 4 inches long, 1/2 ii^ch long, oblong, one-fourth

enclosed by the shallow cup. Bark fissured and flaky, gray. Wood

hard, light brown.

Distribution : Uncommon in mountains and canyons, oak woodland zone, 4,000 to 8,000 feet elevation, in Mexican border region.

New Mexico: mountains of southwestern corner in Luna, Hidalgo,

and Grant Counties north to Mogollón Mountains. Arizona : southeastern part in Cochise, Graham, and Pima Counties ; also in southern Coconino County. Southwestern Texas to Arizona and northern

Mexico.

MEXICAN BLUE OAK (Quercus oblongifolia Torr.)

Description : Small evergreen tree to 25 feet tall, with trunk up

to 1^ feet in diameter and with spreading, rounded crown, or a

shrub at higher elevations. Leaves oblong, 1 to 2 inches long,

rounded at both ends or heart-shaped at base, edges without teeth

(rarely toothed), thin and firm, at maturity without hairs, bluegreen and covered with a bloom above, paler beneath. Acorn I/2 to

% inch long, rounded, one-third enclosed by the cup. Bark fissured
SOUTHWESTERN TREES 47

Netleaf oak. Mexican blue oak. Arizona white oak.

into small, squarish plates, gray. Wood hard, very heavy, brittle,

dark brown.

Distribution: Common and characteristic small tree of oak

woodland in foothills and mountains and sometimes in canyons at

upper edge of desert and desert grassland, 4,500 to 6,000 feet

elevation, in Mexican border region. New Mexico: mountains of

extreme southwestern corner in southern Hidalgo County. Arizona: foothills and mountains in southeastern part (Cochise, Santa

Cruz, and Pima Counties) and in Mohave County. Also in northern

Mexico (Chihuahua and Sonora).

Mexican blue oak, which forms open woodlands of small spreading trees along the Mexican border, is readily distinguished by the

small, blue-green, oblong, toothless and hairless leaves.

ARIZONA WHITE OAK {Quercus arizonica Sarg.)

Also called Arizona oak.

Description : Medium-sized evergreen tree 30 to 60 feet or more

in height and 2 to 3 feet in trunk diameter, with irregular spreading

crown of stout branches. Leaves obovate or oblong, 1 to 3 inches

long, short-pointed or rounded at apex, heart-shaped or rounded

at base, edges slightly wavy-lobed and toothed toward apex, thick

and stiflf, above dull blue-green and nearly hairless and with veins

sunken, beneath paler and densely hairy and with prominent

raised veins, shedding gradually in spring as the new leaves unfold.

Acorn % to 1 inch long, with shallow cup. Bark fissured into thick

plates, light gray or whitish. Wood hard, heavy, dark brown.

Distribution : Common and characteristic tree of the oak woodland, in foothills, mountains, and canyons, 5,000 to 7,600 feet elevation. New Mexico : mountains in southern part, from White, Capitán, and Organ Mountains westward to Mogollón Mountains and

southwest corner. Arizona : mountains in southeastern and central

parts, west to Santa Cruz and Pima Counties and northwest to

Gila and Yavapai Counties. Also in northern Mexico (Chihuahua

and Sonora).

Arizona white oak is probably the largest of the southwestern

oaks, reaching its greatest size in canyons and other moist sites.
48 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

GRAY OAK (Quercus ^risea Liebm.)

Description: Small, low scrubby evergreen tree or shrub, or in

favorable locations a medium-sized tree to 65 feet in height. Leaves

elliptic to ovate, % to 2 inches long, blunt or short-pointed at apex,

rounded or slightly heart-shaped at base, edges without teeth or

with a few teeth toward apex, thin and firm, gray green or blue

green, shiny and sparsely hairy above, beneath densely hairy.

Acorn V^ inch long, rounded, one-third enclosed by the deep cup.

Bark fissured into shaggy plates, light gray. Wood hard, heavy,

brown.

Distribution: Dry rocky mountain slopes and foothills and in

canyons, oak woodland and pinyon-juniper woodland, 5,000 to

7,000 feet elevation. New Mexico : common in mountains of southern and central parts, from Guadalupe, White, and Sandia Mountains and Santa Rosa westward. Arizona: uncommon in mountains of southeastern and central parts, west from Cochise County

and White Mountains to Gila County and Oak Creek Canyon

(Coconino County). Southwestern Texas to Arizona and also in

northern Mexico (Chihuahua and Coahuila).

Gray oak, usually a low, scrub oak, is common in the oak woodland of New Mexico and infrequent westward in Arizona. As this

species intergrades both with Arizona white oak and shrub live

oak, some forms are not readily distinguished.

TOUMEY OAK {Quercus toutneyi Sarg.)

Description : Evergreen shrub 3 to 6 feet tall or small tree to 33

feet in height and 8 inches in trunk diameter. Leaves numerous

and crowded, very small, elliptic or oval, i/4 to % inch long, sharppointed, edges without teeth or infrequently with a few short

teeth, shiny yellow-green above, slightly hairy beneath, shedding

in spring as new leaves appear. Acorn 1/2 to % inch long, with

shallow cup. Bark thin, scaly or flaky, dark brown. Wood light

brown.

Distribution : Local and restricted on hillsides and mountains in

oak woodland, 4,000 to 7,000 feet elevation, Mexican border region ;

not in New Mexico. Arizona : southeastern part, in Cochise, Greenlee, and Santa Cruz Counties. Also in adjacent Sonora, Mexico.

Toumey oak has a restricted distribution, so far as known. It

was discovered in the Mule Mountains of Cochise County in 1899

by James W. Toumey (1865-1932), then botanist at the University

of Arizona and afterwards dean of the Yale University School of

Forestry. Shrubs of this species may be seen in Texas Canyon

along the highway east of Benson in Cochise County.

SHRUB LIVE OAK {Quercus turbinella Greene)

Also called scrub oak, California scrub oak, turbinella oak. Botanical synonyms: Q, dumosa Nutt. var. turbinella (Greene) Jepson, Q. subturbinella Trel.

Description : Evergreen, much-branched shrub usually less than

8 feet tall or rarely a small tree to 15 feet in height with open,

widely spreading crown. Leaves small, elliptic or oblong, 14 to li/4
SOUTHWESTERN TREES 49

Tourney oak. Shrub live oak. Wavyleaf oak. Chinquapin oak.

inch long, short-pointed, edges with many small spinelike teeth,

thick and stiff, above blue-green with a bloom and nearly hairless,

beneath yellowish green and finely hairy. Acorn % inch long, narrow and pointed, with shallow cup. Bark fissured and scaly, gray.

Wood hard, brittle, brown with tan or yellowish sapwood.

Distribution: Abundant as the characteristic species of the

chaparral in Arizona, forming dense thickets and covering hillsides, and also in oak woodland, pinyon-juniper woodland, lower

ponderosa pine forest, and sometimes upper edge of desert, 4,500

to 8,000 feet elevation. New Mexico: mountains of southwestern

part, from Magdalena Mountains westward. Arizona: widely distributed and nearly throughout, but most common in the chaparral

vegetation of the central part, chiefly in Gila, eastern Maricopa,

and Yavapai Counties. New Mexico and Colorado, west to southern

Utah, southern Nevada, and southeastern California, and south

to northern Mexico.

Though generally a shrub in the evergreen shrubby or chaparral

vegetation, this species rarely becomes a small tree at Grand

Canyon and elsewhere. Shrub live oak and other southwestern

oaks provide browse for goats, sheep, and cattle.

WAVYLEAF OAK (Quercus undulata Torr.)

Also called Rocky Mountain shin oak, scrub oak, shinnery.

Description : Usually a low evergreen shrub 1 to 6 feet in height

but sometimes becoming a small tree to 15 feet tall and 4 inches

or more in trunk diameter. Leaves small, varying in shape, elliptical or oblong, 1 to 2^4 inches long, usually flat or wavy margined,

shallowly or wavy lobed or toothed, thick and firm, gray-green,

densely hairy beneath and slightly rough. Acorn % to % inch long,

oblong, rounded at tip, with deep cup nearly half the length.

Bark very scaly, light gray.

Distribution: Dry mountain slopes and canyons, forming dense

brush, pinyon-juniper woodland, oak woodland, and ponderosa pine

forest zones, commonly at 5,000 to 7,000 feet elevation but sometimes to 4,000 and 9,000 or 10,000 feet. New Mexico: widely distributed in foothills and mountains over the State, from Guadalupe
50 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

and Organ Mountains northward; common across northern part

to northeastern corner. Arizona : mountains in southeastern corner

(Cochise County) and in northern part (Navajo, Coconino, and

Mohave Counties). Southwestern Texas and New Mexico to Colorado, west to southern Utah and Nevada, and south to Arizona and

northern Mexico.

Wavyleaf oak is usually a low, carpet-forming shrub occupying

large areas of foothills and spreading by sprouts from underground

branches. However, in moist protected places at lower elevations,

such as in Grand Canyon, it becomes a low tree. It is often common

on burned areas.

CHINQUAPIN OAK (Quercus muehlenbergii Engelm.)

Description : Small tree to 25 feet in height (in eastern United

States a large tree). Leaves oblong or broadly lance-shaped, 3 to 6

inches long, short- or long-pointed, usually rounded at base, edges

wavy with coarse, slightly curved teeth, dark or yellowish green

above, paler and finely hairy beneath. Acam 1/2 to % inch long,

rounded, half enclosed by the deep cup. Bark thin, fissured, and

flaky, light gray. Wood heavy and hard.

Distribution : Very rare and local in mountain canyons of pinyonjuniper woodland, about 7,000 feet elevation, in mountains bordering the plains in eastern New Mexico ; not in Arizona. New Mexico :

known from two places in the vicinity of Capitán Mountains

(Lincoln County) ; reported from Coyote Creek near Guadalupita

(Mora County) ; and collected in Guadalupe Mountains of southwestern Texas near New Mexico border and on other mountains

in southwestern Texas. Also widely distributed in eastern United

States from northwestern Florida north to Vermont and southern

Ontario, west to Wisconsin and Iowa, and south to Texas. A variety

extends south from Texas into northern Mexico.

Chinquapin oak is too rare in New Mexico to be important but is

noteworthy because of its unusual distribution. These isolated

Rocky Mountain localities are some distance westward of the limits

of continuous distribution of this species in western Oklahoma and

central Texas.

GAMBEL OAK {Quercus gambelii Nutt.)

Also called Utah white oak, Rocky Mountain white oak. Botanical synonyms: Q. gunnisonii (Torr.) Rydb., Q. leptophylla Rydb.,

Q. novo'ïnexicana (A. DC.) Rydb,, Q. subTnollis Rydb., Q, utahensis

(A. DC.) Rydb.

Description : Small to medium-sized tree 20 to 70 feet tall with

trunk 2 to 4 feet in diameter and with rounded crown, or a shrub

as low as 6 feet in height and growing in thickets. Leaves oblong,

2 to 7 inches long, deeply 7- to 11-lobed halfway or more to middle,

edges without teeth, dark green above, light green and soft-hairy

beneath, varying greatly in size, lobing, and hairiness, turning

yellow and reddish in autumn before shedding. Acorn % to %

inch long, broad and rounded, with deep cup. Bark rough, thick,

deeply furrowed or scaly, gray. Wood hard, heavy, light brown.
SOUTHWESTERN. TREES 51

Gambel oak. Palmer oak. Emory oak.

Distribution: Common and widespread in mountains and

plateaus in ponderosa pine forest, 5,000 to 8,000 feet elevation. New

Mexico : widely distributed in mountains of western two-thirds and

northeastern corner, from Sacramento and Organ Mountains, Black

Range, and Mogollón Mountains northward. Arizona: mountains

and plateaus of northeastern half, from Chiricahua Mountains to

Kaibab Plateau. Southwestern Texas north to Colorado, west to

southwestern Wyoming, Utah, and southern Nevada, and south to

Arizona and northern Mexico (Chihuahua and Coahuila).

Gambel oak is easily recognized by the deeply lobed leaves, which

are larger than those of other southwestern oaks and which are

shed in autumn. This is the only common tree oak in the northern

parts of New Mexico and Arizona. The wood is used for fence posts

and fuel. This familiar southwestern oak and the equally familiar

Gambel quail commemorate William Gambel, a physician, ornithologist, and botanist of Philadelphia, who "passed through Santa Fe,

N. Mex., in 1841 on his way to California'* and discovered about a

hundred new species of plants on the expedition.

PALMER OAK {Quercus chrysolepis Liebm. var. palmeri

(Engelm.) Sarg.)

Also called canyon live oak. Botanical synonyms: Q. palmeri

Engelm., Q. wilcoxii Rydb.

Description : Evergreen shrub or small tree usually 6 to 25 feet

tall and up to 6 inches in trunk diameter, with dense, bushy, broad

crown of many stiff branches and spiny-toothed leaves. Leaves

elliptic to ovate, % to 2 inches long, short-pointed, edges crisp and

spiny toothed, stiff and very leathery, shiny yellow-green above,

beneath slightly yellowish and resinous hairy but becoming whitish.

Acorn % to iVj inches long, broad or narrow, maturing in 2 years;

the cup large, spreading, and loosely fitting the acorn, finely hairy

inside and covered with fine coat of golden hairs. Bark fissured

into narrow scales and flakes, gray or brown. Wood hard, heavy,

light brown.

Distribution: Canyons and mountainsides, often forming thickets, oak woodland, elevation 3,500 to 7,000 feet. New Mexico:
52 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

mountains in southwestern corner (Hidalgo and Grant Counties),

Arizona: mountains of southeastern and central parts, from Cochise and Greenlee Counties west to Pima County and northwest

below Mogollón Rim to southern Coconino County (Oak Creek

Canyon) and Yavapai County and west to Hualpai Mountains ; also

at Bright Angel Canyon near Grand Canyon. This variety also in

southwestern Utah, southern Nevada, southern California, and

south to northwestern Mexico (Sonora and Lower California). Canyon live oak, the typical form of this species, is found in California,

southwestern Oregon, and Lower California, Mexico.

Palmer oak has spiny evergreen leaves resembling those of holly

and is attractive in winter. It honors Edward Palmer (1831-1911),

American botanical collector who obtained numerous specimens in

Mexico and southwestern United States during many years of

exploration.

EMORY OAK {Quercus emoryi Torr.)

Also called black oak, blackjack oak, bellota.

Description: Medium-sized evergreen tree to 50 feet in height

and 214 feet in trunk diameter. Leaves broadly lance-shaped, 1 to

2% inches long, with a short spiny point and a few short spiny

teeth, thick, stiff, leathery, flat, shiny yellowish green on both

sides, nearly hairless, shedding gradually in spring as the new

leaves unfold. Acorn ^ to % inch long, rounded, one-third or

more enclosed by the cup, sweetish and edible. Bark thick, divided

into thick plates, black. Wood hard and heavy, dark brown with

thick lighter sapwood.

Distribution: The most abundant and most characteristic tree

of the oak woodland in the Mexican border region, in foothills,

mountains, and canyons and sometimes also in canyons at upper

edge of desert and desert grassland, 4,000 to 7,000 feet (rarely

8,000 feet) elevation. New Mexico: mountains of southwestern

corner, from Black Range southwestward. Arizona : mountains of

southeastern and central parts, west to Santa Cruz and Pima Counties and northwest below Mogollón Rim to Gila County, southern

Coconino County (Oak Creek Canyon), and Yavapai County. Also

in southwestern Texas and northern Mexico.

Emory oak is named from Lt. Col. W. H. Emory (1811-87),

leader of a military expedition in the Southwest in 1846-47, during

the Mexican War, who ñrst collected specimens of this species at

Pigeon Creek (Las Palomas), within the present Sierra County,

N. Mex. In moist places, especially in canyons, Emory oak forms

fairly dense forests. It is one of the most important sources of

firewood in southern Arizona. The acorns, known in Spanish as

bellotas, are nearly free from tannin with its bitter taste and are

gathered and eaten locally by Indians and Mexicans.

SILVERLEAF OAK (Quercus hypoleucoides A. Camus)

Also called whiteleaf oak. Botanical synonym: Q. hypoleuca

Engelm., not Miq.

Description: Small to medium-sized evergreen tree to 30 feet

to 65 feet in height and II/2 to 214 f^^t in trunk diameter, with a
SOUTHWESTERN TREES 53

rounded spreading crown, or sometimes a clump-forming shrub 6

feet tall. Leaves lance-shaped, 2 to 4 inches long and i/^ to 1

inch wide, sharp-pointed, narrowed at base, edges rolled under

and usually without teeth or with a few small spiny teeth, very

thick and leathery, shiny yellow-green above, beneath densely

white-woolly. Acorn 1/2 to % inch long, pointed, one-third enclosed

in a thick cup hairy inside, maturing in 2 years. Bark deeply furrowed into ridges and plates, blackish. Wood hard, heavy, dark

brown.

Distribution: More or less common in mountain slopes and

canyons of oak woodland, 5,000 to 7,000 feet elevation, in Mexican

border region. New Mexico: mountains of southwestern part north

to Black Range and Mogollón Mountains. Arizona : mountains of

southeastern part west to Santa Cruz, Pima, and Graham Counties.

Southwestern Texas to southeastern Arizona and in northern

Mexico.

Silverleaf oak with its leaves so distinct from those of most oaks

should be suitable for cultivation as an ornamental tree.

Elm Family (Ulmaceae)

NETLEAF HACKBERRY {feltis reticulata Torr.)

Also called paloblanco, western hackberry. Botanical synonym :

C. laevigata Willd. var. reticulata (Torr.) L. Benson.

Description : Large shrub or small tree to 30 feet tall and 1 foot

or more in trunk diameter, with spreading crown. Leaves in 2

rows, very variable, mostly ovate, 1 to 21/2 inches long, one-sided,

short- or long-pointed, base rounded or slightly heart-shaped and

with 3 main veins, edges without teeth or sometimes coarsely sawtoothed, usually thick, dark green and rough above, beneath

yellow-green, strongly veined, and slightly hairy, shedding in

autumn or winter. Flowers small, greenish, in March and April.

Fruit % to % inch in diameter, orange-red, dry and sweet, 1-seeded.

Bark smoothish or becoming rough and fissured, with large corky

warts, gray. Wood light brown.

Distribution: Usually along streams, canyons, and washes, in

moist soil, plains grassland, upper desert, desert grassland,

and oak woodland zones, 2,500 to 6,000 feet elevation, widely distributed. New Mexico : plains of eastern part from Union County

south and southwest ; mountains across southern part, north along

Rio Grande drainage to Sandia Mountains, and in Gila River drainage. Arizona : mountains and streams of southeastern and central

parts south of Mogollón Rim, northwest to Yavapai and Mohave

Counties ; also along Colorado River and tributaries across northern

part. Southern and central Texas and Oklahoma, west to Colorado,

Arizona, and California. Also in northern Mexico.

The wood is used for fuel and fence posts, and the sweetish fruits

are eaten by wildlife and can be nibbled. Many leaves have rounded,

swollen galls caused by insects, while the branches often have

witches' broom galls.
54 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Mulberry Family (Moraceae)

TEXAS MULBERRY (Morus microphylla Buckl.)

Also called Mexican mulberry and mountain mulberry.

Description: Small scrubby tree or large shrub to 20 feet tall

and 6 inches in trunk diameter, often growing in dense clumps.

Leaves in 2 rows, variable in shape, ovate and often 3- to 5-lobed,

1 to 2 inches long, short-pointed, base rounded or heart-shaped

and with 3 main veins, edges coarsely saw-toothed, dark green

and rough above, beneath paler and usually hairy. Male and female

flowers in dark green catkins on different trees (dioecious), appearing with the leaves in April. Mulberry fruit on oblong cluster

about 1/2 inch long, turning from red to purple or black, juicy and

acid, edible. Bark smoothish, light gray, becoming fissured and

scaly. Wood hard, heavy, dark orange or brown.

Distribution : Common, usually along streams, canyons, washes,

or rocky slopes below cliffs, in foothills and mountains, woodland

and upper desert zones, 2,000 to 6,000 feet elevation, widely distributed. New Mexico: foothills and mountains across southern

part, north to White Mountains and Black Range. Arizona: mountains in southern and central parts west to Santa Cruz and Pima

Counties and Kofa Mountains (Yuma County) and north to

Yavapai County. Central Texas west to Arizona and south to

northern Mexico.

The small mulberry fruits are eaten by Indians and by wildlife.

This species is established at Grand Canyon, where the Havasupai

Indians cultivate the trees for the fruits.

Sycamore Family (Platanaceae)

ARIZONA SYCAMORE {Platanus wrightii S. Wats.)

Also called Arizona planetree. Botanical synonym : P. racemosa

Nutt. var. wrightii (S. Wats.) L. Benson.

Description : Large tree 40 to 80 feet in height, with large trunk

to 4 feet or more in diameter and with large spreading branches

and broad open crown. Leafstalks II/2 to 3 inches long, stout, the

enlarged base enclosing the bud. Leaves slightly star-shaped, large,

6 to 10 inches long and wide, heart-shaped at base, deeply divided

into usually 5 or 3 (or 7) narrow, long-pointed lobes, the edges

mostly without teeth, thin and firm, light green and hairless above,

beneath pale and hairy. Flowers male and female, in clusters of

usually 2 to 4 balls, in March and April. Fruit of 2 to 4 stalked

balls % to 1 inch in diameter, along a stalk 6 to 8 inches long.

Bark of branches smooth, thin, whitish ; bark of largest branches

and trunk smoothish and peeling off in brownish flakes, on large

trunks becoming thick, dark gray, and deeply and irregularly

divided into thick plates. Wood light brown.

Distribution: Common along streams and rocky canyons in

foothills and mountains, upper desert, desert grassland, and oak

woodland zones, 2,000 to 6,000 feet elevation. New Mexico: south-
SOUTHWESTERN TREES 55

Netleaf hackberry. Texas mulberry. Arizona sycamore. Torrey vauquelinia.

western corner, from Black Range and Mogollón Mountains southwestward. Arizona : southeastern and central parts, west to Santa

Cruz and Pima Counties and northwest in central part to Mogollón

Rim, southern Coconino County, Yavapai County, and southeastern

Mohave County. Also local in southeastern California and in

Sonora and Chihuahua, northern Mexico.

Arizona sycamore, one of the largest and handsomest deciduous

tree species in Arizona, is valuable in preventing erosion along

stream banks.

Rose Family (Rasaceae)

TORREY VAUQUELINIA (Vauquelinia californica (Torr.)

Sarg.)

Also called Arizona rosewood.

Description : Evergreen small tree 10 to 30 feet tall, with trunk

14 to 11/^ feet in diameter, with stiff twisted branches and slender

twigs, or a low, much-branched shrub. Leaves narrowly lanceshaped, IV2 to 4 inches long and 14 to % inch wide, long-pointed,

edges saw-toothed, leathery, bright yellow-green, finely hairy beneath. Flowers many in dense clusters 2 to 3 inches across, small,

% inch across, white, in May and June. Fruit a hard capsule l^

inch long, hairy, splitting into 5 2-seeded parts, remaining attached during winter. Bark thin, broken into small square scales

or shaggy, dark red brown. Wood hard, very heavy, dark brown

streaked with red.

Distribution : Canyons and mountains in upper desert and lower

oak woodland, 2,500 to 5,000 feet elevation, Mexican border region.

New Mexico : known only from Guadalupe Canyon (Hidalgo

County) in southwestern corner. Arizona : scattered on mountains

of southeastern part from Guadalupe and Whetstone Mountains

(Cochise County) west to Ajo Mountains (Pima County) and

north to Superstition Mountains and Sierra Estrella (Maricopa

County). Also in southwestern Texas and northwestern Mexico

(Sonora and Lower California).

The hard, heavy wood is beautiful and suggested the name
56 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Arizona rosewood. However, commercial use has been limited by

the small size and scarcity of the trees and their slow growth.

Vauquelinia honors the French chemist Louis Nicholas Vauquelin

(1763-1829).

UTAH SERVICEBERRY (Amelanchier utahensis Koehne)

Botanical synonyms: A. australis Standl., A, bakeri Greene,

A. crenata Greene, A, goldmanii Woot. & Standl., A. mormonica

Schneid., A. oreophila A, Neis., A. rubescens Greene.

Description: Shrub or small tree 5 to 16 feet tall, much-branched

and often forming clumps. Leaves very variable, nearly round to

elliptic, small, 1/2 to ll^ inches long, rounded at apex and base,

edges coarsely and often sharply toothed above middle, slightly

leathery at maturity, grayish green, finely hairy on both sides.

Flowers 3 to 6 in cluster, about 1/2 inch long, with 5 white petals,

from April to June. Fruit 14 to % inch in diameter, resembling a

small apple, bluish black, juicy and sweet, or often pale brown,

dry and mealy. Bark smooth, ashy gray.

Distribution: Scattered in canyons, rocky slopes, foothills, and

mountains in pinyon-juniper woodland and ponde^,osa pine forest

and sometimes also in upper desert, 2,000 to 8,5(^ feet elevation.

New Mexico : widely distributed in mountains over the State, except

along eastern and southern borders, from San Andres Mountains

(Dona Ana County) and Sandia and Las Vegas Mountains westward. Arizona: mountains and canyons of central and northern

parts, from southern Apache County west to Gila and Yavapai

Counties and northward; common at Grand Canyon. Widely distributed from southwestern Texas north to Wyoming and southern

Montana, west to Oregon, and south to California and Lower California, Mexico.

The fruits are eaten by wildlife and were consumed by the Indians fresh or dried, though in arid localities the fruits may remain

dry and insipid and not become juicy. The foliage is good to excellent browse for sheep and cattle.

FIREBERRY HAWTHORN {Crataegus chrysocarpa Ashe)

Botanical synonym : C. rotundifolio. Moench, not Lam.

Description: Spiny shrub or small tree with rounded crown.

Twigs hairy when young, with many spines % to 21/2 inches long.

Leaves broadly ovate or nearly round, 114 to 2 inches long, shortpointed, broadly wedge-shaped at base, slightly 7- or 9-lobed,

coarsely and doubly saw-toothed, firm, dark green above and paler

beneath, loosely hairy on both sides. Flowers in clusters, white, %

inch or less across. Fruit about % inch in diameter, orange or red, '

resembling a small apple, with thin ñesh and bony nutlets.

Distribution: Recorded from New Mexico; not in Arizona.

Widely distributed from Nova Scotia and New Brunswick west to

Saskatchewan and North Dakota, south to Nebraska, Colorado, and

New Mexico, and in eastern United States south to Michigan and

North Carolina.
SOUTHWESTERN TREES 57

Utah serviceberry. Fireberry hawthorn. River hawthorn. Cerro hawthorn.

RIVER HAWTHORN (Crataegus rivularts Nutt.)

Also called black haw.

Description : Spiny shrub or small tree to 20 feet tall, with open

crown, often forming clumps. Twigs more or less zigzag, shiny reddish brown, often with a few straight, slender, sharp spines 1 inch

or less in length. Leaves elliptic, about 2 inches long and less than 1

inch wide, mostly short-pointed, tapering at base, finely sawtoothed but not lobed, thin, without hairs at maturity, blue-green

above, pale yellow-green beneath. Flowers several in cluster, 1/2

inch across, white. Fruit % to 1/2 inch in diameter, dark red but

turning black, shiny, resembling a small apple, with thin mealy

flesh and 3 to 5 large bony nutlets.

Distribution : Local and scattered along streams and canyons in

mountains, pinyon-juniper woodland and ponderosa pine forest

zones, 5,000 to 6,000 feet elevation. New Mexico: northern part;

also collected at Upper Negrito Creek (Catron County). Arizona:

collected at Clear Creek Canyon southeast of Winslow (Navajo

County). New Mexico north to Wyoming, west to Idaho and Nevada, and south to Arizona.

CERRO HAWTHORN {Crataegus erythropoda Ashe)

Also called manzana de puya larga. Botanical synonym: C

cerronis A. Neis.

Description: Spiny shrub or small tree to 15 feet in height.

Twigs more or less zigzag, with many stout sharp purplish spines

3^ to 2 inches long, without hairs, purplish. Leaves ovate, 1 to 21/2

inches long, less than twice as long as wide, short-pointed, wedgeshaped at base, often shallowly 3- to 7-lobed, coarsely saw-toothed,

bright green and without hairs. Flowers in clusters 1 to 2V2 inches

broad, white. Fruit about % inch in diameter, orange-red, resembling a small apple, with thin flesh and large bony nutlets.

Distribution: Uncommon along streams and canyons, pinyonjuniper woodland and ponderosa pine forest, 5,400 to 8,000 feet

elevation. New Mexico: mountains in northern part from Coifax

County south to Sandia Mountains. Arizona : uncommon and local,
58 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

collected in White Mountains (Apache County) and Oak Creek

Canyon (Coconino County). New Mexico north to Wyoming, west

to Washington, and south to Arizona.

Another species of hawthorn {Crataegus wootoniana Eggleston), described as a shrub 10 feet or less in height, occurs in the

White Mountains and Mogollón Mountains of southern and southwestern New Mexico. It has broadly ovate, saw-toothed leaves with

3 or 4 pairs of broad lobes.

CLIFFROSE {Cowania stansburiana Torn)

Also called quinine-bush. Botanical synonym: C mexicana

D. Don var. stansbu7^iana (Torr.) Jeps.

Description: Small-leaved evergreen, spreading shrub 3 to 6

feet tall or sometimes becoming a small scrubby tree to 25 feet in

height and 6 inches in trunk diameter, with irregular open crown

of stiff erect branches. Twigs hairy, glandular, and reddish brown

the first year, becoming hairless and gray. Leaves crowded and

small, ^4 to % inch long, wedge-shaped, divided into 3 to 7 narrow

lobes, thick and leathery with edges rolled under, with white sticky

resinous dots, above dark green and loosely hairy or almost hairless,

beneath densely white-woolly, bitter. Flowers many but borne

singly, large, % to 1 inch across, whitish or pale yellow, fragrant,

March to September. Fruits 5 to 10 clustered from a flower, 14

inch long, each with long feathery or plumy, whitish tail (style)

V/i to 2 inches long. Bark shreddy, splitting into long narrow

strips, reddish, brown, or gray. Wood brown, with thin whitish

sapwood.

Distribution: Common on dry rocky hills and plateaus, especially on limestone, in upper desert, desert grassland, oak woodland, and pinyon-juniper woodland zones, 3,500 to 8,000 feet elevation. New Mexico: western part, west of Rio Grande, from Black

Range westward and northwest to San Juan River drainage. Arizona : widely distributed across central and northern parts and also

in mountains of southeastern part, from mountains of Cochise and

Santa Cruz Counties north to northern border of State and west

to Hualpai Mountains. Western New Mexico north to southern

Colorado, west to northern Utah, Nevada, and eastern California,

and south across Arizona to northern Mexico (Sonora and Chihuahua).

Cliifrose is an important browse plant for deer, cattle, and sheep.

Covered with whitish flowers, it is beautiful when in full bloom and

should be an attractive ornamental. It is planted also for erosion

control.

CURLLEAF MOUNTAIN-MAHOGANY (Cercocarpus ledifolius

Nutt.)

Botanical synonym: C ledifolius var. intercedens C. K, Schneid.

Description: Evergreen spreading shrub or small tree to 15 or

sometimes 20 feet tall and i/^ to 2 feet in trunk diameter, with compact rounded crown of widely spreading branches and many stiff

twigs. Leaves usually clustered, narrowly lance-shaped or elliptic.
SOUTHWESTERN TREES 59

^^ih*^

Cliffrose. Curlleaf mountainmahogany.

Hairy mountain- Birchleaf mountainmahogany, mahogany.

1/^ to ll^ inches long and less than % inch wide, short-pointed at

both ends, edges without teeth and rolled under, thick and leathery,

shiny dark green above, pale and finely hairy beneath, resinous and

slightly aromatic. Flowers single in leaf axils, % inch long, yellowish, in April. Fruit l^ inch long, hairy, with a twisted hairy tail

(style) 11/^ to 3 inches long. Bark thick, furrowed and scaly, reddish brown. Wood very hard, heavy, red or dark brown with thin

yellow sapwood.

Distribution: Common locally on both rims of Grand Canyon,

northern Arizona, in ponderosa pine forest zone, about 7,000 feet

elevation ; not in New Mexico. Arizona : known only from Grand

Canyon. Southwestern Colorado north to Montana, west to Washington, and south to southern California and northern Arizona.

HAIRY MOUNTAIN-MAHOGANY {Cercocarpus breviflorus

A. Gray)

Also called Wright mountain-mahogany. Botanical synonyms:

C. pauddentatus (S. Wats.) Britton, C. montanus Raf. var. paucidentatus (S. Wats.) F. L. Martin.

Description: Evergreen shrub or small tree to 15 feet or more

in height and 5 inches in trunk diameter, with open crown of widely

spreading branches and long slender twigs. Leaves obovate or

reverse lance-shaped, % to 1 inch long and ^4 to y% inch wide,

rounded or short-pointed at apex and tapering from above middle

to base, edges turned under and usually with a few rounded teeth

near apex, thick, dark green and hairless or slightly hairy above,

pale and finely hairy beneath. Flowers 1 to 3 in leaf axils, about Vè

inch long, yellowish, March to November. Fruit l^ inch long, redbrown, hairy, with a twisted white-hairy tail (style) 1 to IV2

inches long. Bark thin, smoothish, becoming fissured .and scaly,

gray or red-brown. Wood hard, light brown with light yellow

sapwood.

Distribution: Common on dry slopes and mountainsides, chaparral and oak woodland, 5,000 to 8,000 feet elevation. New Mexico:
60 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

mountains of southern and central parts, from Guadalupe Mountains north to Capitán Mountains and Santa Fe County and west to

Black Range and San Luis Mountains. Arizona: mountains of

southeastern and central parts, from Cochise County to southern

Apache County and west to southern Coconino, Yavapai, and Pima

Counties. Southwestern Texas to central Arizona, south to northern Mexico.

This species and birchleaf mountain-mahogany are important

browse plants for livestock.

BIRCHLEAF MOUNTAIN-MAHOGANY {Cercocarpus betuloides

Null.)

Botanical synonym: C. montanus Raf. var. glaber (S. Wats.)

F. L. Martin.

Description: Evergreen large spreading shrub or small tree to

20 feet in height with a single trunk to 6 inches in diameter and

spreading crown. Leaves obovate to oval, 1 to m inches long and

% to V2 inch wide, rounded at apex and wedge-shaped at base,

finely toothed above middle, slightly thick, dark green above, pale

green or grayish and slightly hairy beneath. Flowers 1 to 3 in

leaf axils, about Vè inch long, yellowish, March to July. Fruit

hairy, with a twisted hairy tail (style) 2 to 3 inches long. Bark

of thin scales, smoothish.

Distribution : Chaparral zone of mountains in Arizona, 3,500 to

6,500 feet elevation; not in New Mexico. Arizona: mountains,

chiefly across the central part, from Cochise County (Winchester

Mountains) to southern Apache County and west to Gila, Coconino

(Grand Canyon), Mohave (Hualpai Mountains), and Yuma

(Harqua Hala Mountains) Counties. Also in Oregon, California,

and Lower California, Mexico.

BITTER CHERRY (Prunus emarginata (Dougl.) D. Dietr.)

Also called wild cherry. Includes the variety P. emargiTiata var.

crenulata (Greene) Kearney & Peebles (botanical synonym,

Cevdsus crenulata Greene).

Description: Small tree or shrub to 13 feet or more in height,

with slender upright branches. Twigs red, slender, hairy when

young. Leaves varying in shape, oval or elliptic to reverse lanceshaped, 1 to 2 inches long, rounded or short-pointed at apex, edges

minutely saw-toothed with blunt gland-tipped teeth, dark green

above, pale and sometimes hairy beneath, very bitter. Flowers few

in short clusters 1 to IV^ inches long, % to 14 inch across, white,

April to June. Fruit a red cherry about % inch in diameter, juicy,

acid and bitter, with a large stone. Bark smooth, purplish or reddish brown, very bitter. Wood soft and brittle, brown streaked

with green.

Distribution: Mountains in ponderosa pine forest, 5,000 to 9,000

feet elevation. New Mexico : mountains of southwestern part, Black

Range and Mogollón Mountains. Arizona : mountains of southeastern and central parts, from Cochise County west to Pima County
SOUTHWESTERN TREES 61

Bitter cherry. Common chokecherry. Southwestern American plum.

chokecherry.

and northwest to Coconino County and Hualpai Mountains. New

Mexico north to British Columbia, south to southern California and

Arizona.

COMMON CHOKECHERRY (Prunus virginiana L.)

Also called wild cherry. Includes two varieties in the Southwest, not distinguished here: black chokecherry (P. virginiana

var. melanocarpa (A. Neis.) Sarg. ; also called black western chokecherry) and western chokecherry (P. virginiana var. demissa

(Nutt.) Torr.). Botanical synonym: Padus valida Woot. & Standl.

Description: Shrub or small tree to 25 feet in height, with a

trunk 6 inches or more in diameter, often forming dense thickets.

Leaves varying in shape and hairiness, oval to obovate, 2 to 4

inches long, abruptly short-pointed at apex, rounded or heartshaped at base, edges sharply saw-toothed, thick, above shiny dark

green, beneath light green and without hairs or slightly hairy.

Flowers many in clusters 3 to 6 inches long, small, % to Vè inch

across, white, in April and May. Fruit a chokecherry i/4 to % inch

in diameter, at maturity dark red or nearly black, shiny, juicy and

astringent, with a large stone. Bark smooth and brown or gray on

small trunks, becoming fissured and scaly. Wood hard and heavy,

light brown.

Distribution: Widely distributed, especially along streams in

mountains, ponderosa pine forest, 4,500 to 8,000 feet elevation.

New Mexico: mountains of western two-thirds and northeastern

corner, from Sacramento Mountains north to Las Vegas and Raton

Mountains and westward. Arizona: mountains and plateaus of

northeastern third, from Greenlee County north to Lukachukai

Mountains (Apache County) and west to Gila County and north

rim of Grand Canyon. This species including varieties has a very

broad range from New Foundland and Quebec west to British

Columbia and south to California, Texas, and Georgia.

Chokecherries are eaten by wildlife and are sometimes used in

making preserves and jelly. However, as the common name suggests, they are astringent when raw.
62 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

SOUTHWESTERN CHOKECHERRY {Prunus virens (Woot. &

Standl.) Shreve)

Also called Gila chokecherry, Chisos wild cherry. Botanical

synonyms: P. rufula Woot. & Standl., P. virens var. rufvia (Woot.

& Standl.) Sarg.

Description: Small to medium-sized tree to 40 feet in height

and 2 feet in trunk diameter, with spreading crown, or a large

shrub. Leaves elliptic, li/^ to 2 inches long, short-pointed at apex

and base, edges finely saw-toothed, shiny light green above, beneath

paler and without hairs or with rusty brown hairs along midrib.

Flowers many in clusters 3 to 6 inches long, small, l^ inch across,

white, in April and May. Fruit a chokecherry about % inch in

diameter, with calyx remaining attached at base, purplish black

and shiny, juicy but astringent, with a large stone. Bark fissured

into thin flat plates, gray, on larger trunks rough and scaly, black.

Distribution: Common, usually along streams and in canyons,

mountains in oak woodland zone, 4,500 to 7,500 feet elevation.

New Mexico: mountains of southern part, from Sacramento and

White Mountains west to Black Range and Mogollón Mountains

and southward. Arizona: mountains of southeastern and central

parts, from Cochise to southern Apache County, west to Santa Cruz

County and northwest below Mogollón Rim to Oak Creek Canyon

(Coconino County) and Mohave County. Southwestern Texas west

to Arizona and south to northern Mexico.

AMERICAN PLUM {Prunus americana Marsh.)

Also called wild plum.

Description : Shrub or small tree to 10 feet or more in height,

sometimes slightly spiny, often forming dense thickets. Twigs

stout and stiff, widely spreading, the short lateral twigs often ending in spines. Leaves oval, 2 to 4 inches long, long-pointed, narrowed at base, sharply saw-toothed, thick and firm, appearing

slightly wrinkled, dark green above and paler beneath, hairless or

nearly so. Flowers 2 to 5 in a cluster, % to 1 inch across, white,

in April before the leaves. Fruit a plum about % inch in diameter,

yellowish red, juicy, acid, and edible, with large stone. Bark gray.

Wood hard and heavy, dark brown tinged with red.

Distribution: Moist soil along streams, ditches, and hillsides

and as an escape from cultivation, 5,000 to 7,200 feet elevation;

not native in Arizona. New Mexico: apparently native in mountains of northeastern New Mexico, though in places it probably

has spread from planted trees ; recorded from Raton to Las Vegas,

Pecos, and Taos, from White Mountains, and from Farmington

perhaps as introduced.

The fruits of this wild plum are widely used in making preserves

and jellies. As the plants form dense thickets they are excellent

for erosion control and have been grown in quantities for this purpose. Over 200 named varieties of this native plum have been selected for cultivation, and its "blood** appears in at least 50 named

and cultivated varieties.
SOUTHWESTERN TREES 63

Catclaw acacia. Sweet acacia.

Legume Family (Leguminosae)

LITTLELEAF LYSILOMA (Lysiloma microphylla Benth.)

Botanical synonyms: L. watsoni Rose, L. thornberi Britton &

Rose.

Description : Shrub to 10 feet tall, dying back in severe winters;

in cultivation a small tree 10 to 15 feet tall and 5 inches in trunk

diameter, with spreading crown of dense feathery foliage; in

Mexico a tree to 40 feet in height. Leaves numerous, bipinnately

compound, 4 to 6 inches or more in length, with 4 to 9 pairs of

primary divisions (pinnae), each with 25 to 33 pairs of feathery,

oblong leaflets about ^4 inch long, nearly hairless or slightly hairy.

Flowers crowded into balls % inch in diameter, whitish, in May

and June. Pod 4 to 9 inches long, broad and flat. Bark fissured

and scaly, light brownish gray. Wood hard, brittle, dark brown.

Distribution: Very rare and local on rocky hillsides in upper

desert and desert grassland, 2,800 to 4,000 feet elevation, known

from two localities in southern Arizona ; not in New Mexico. Arizona: Pima County, near Chimney Creek on western slopes of

Rincón Mountains and in Baboquivari Mountains. Also widely distributed from northwestern Mexico to West Indies.

The plants of this Mexican species at its northern limit in

southern Arizona may be relics of wider distribution in the past.

They have large bases and are killed back by cold winters. This

handsome shrub is planted at the Boyce Thompson Southwestern

Arboretum at Superior, Ariz., and at Phoenix. It should be suitable

as an ornamental in warmer areas, although subject to occasional

winter kill.

CATCLAW ACACIA (Acacia greggii A. Gray)

Also called catclaw, devilsclaw, uña de gato. Botanical synonym :

Senegalia greggii (A. Gray) Britton & Rose.

Description: Spiny, large spreading shrub or occasionally a

small tree to 23 feet tall and 8 inches in trunk diameter, muchbranched, with broad crown. Twigs light reddish brown or pur-
64 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

plish, angled, finely hairy, with scattered stout curved spines ^4

inch or less in length. Leaves bipinnately compound, 1 to 3 inches

long, with 2 or 3 pairs of primary divisions (pinnae), each with

4 to 6 pairs of oblong, usually hairy leaflets l^ inch or less in

length. Flowers in dense clusters V/2 to 2 inches long and 1/2 inch

in diameter, pale yellow, fragrant, from April to October. Pod

2V2 to 5 inches long and 1/2 inch broad, flat, pale brown, often

twisted and narrowed between the shiny brown seeds, remaining

attached in winter. Bark thin, fissured into narrow scales, gray.

Wood hard and heavy, the heartwood reddish brown and sapwood

yellow.

Distribution: Often common to abundant, forming thickets along

washes, slopes, and rocky canyons in desert and desert grassland,

from slightly above sea level to 5,000 feet elevation. New Mexico:

chiefly in southern part, north to Roswell in Pecos River valley

and at Santa Rosa, north to Albuquerque in Rio Grande valley,

and in Gila River drainage in Grant and Catron Counties. Arizona :

widely distributed in southwestern two-thirds, north to Greenlee

County and northwest below Mogollón Rim to Mohave County;

also abundant in depths of Grand Canyon. From southern and

central Texas west and northwest to southwestern Utah, southern

Nevada, and southeastern California. Also in northern Mexico.

Catclaw acacia is to be avoided because of the sharp stout spines

or prickles like a cat's claws, which tear clothing and flesh. The

strong, heavy wood with contrasting heartwood and sapwood is

used for souvenirs, locally for tool handles and similar objects, and

also for fuel. The flowers are a good source of honey. Indians made

meal from the seeds.

SWEET ACACIA (Acacia farnesiana (L.) WiUd.)

Also called huisache. Botanical synonym : Vachellia farnesiana

(L.) Wight & Arn.

Description : Spiny shrub or small tree to 20 feet tall and 1 foot

in diameter at base, with widely spreading crown. Twigs with

white, straight, slender spines Vs to V2 inch long or larger in pairs

at nodes. Leaves bipinnately compound, 2 to 4 inches long, with

usually 3 to 6 pairs of primary divisions (pinnae), each with 10 to

25 pairs of narrow leaflets Vs to 14 inch long, often slightly hairy.

Flowers in balls % inch in diameter, golden yellow, very fragrant,

from April to November. Pod 2 to 21/2 inches long and 14 to %

inch in diameter, not flattened, hard. Bark thin, ridged and scaly,

reddish brown. Wood hard and heavy, reddish brown with thin

pale sapwood.

Distribution: Very rare in desert grassland and lower oak

woodland, 3,500 to 5,000 feet elevation, known from two localities

in southern Arizona; not in New Mexico. Arizona: Mexican border

at Sycamore Canyon near Ruby (Santa Cruz County) and Baboquivari Mountains (Pima County). Native also in southern Texas

and collected at Otay, San Diego County, Calif. Widely planted

and naturalized in southern United States from Florida to Texas

and California. Also in Mexico, Central America, and South

America.
SOUTHWESTERN TREES 65

Western honey Velvet mesquite.

mesquite.

Fremont California redbud.

screwbean.

Cultivated as an ornamental because of the fragrant flowers. In

southern Europe extensively grown for the flowers, known as

cassie flowers, from which perfume is made.

Mescat acacia, or "white-thorn" (Acacia constricta Benth.), a

closely related species, is a common, smaller, branching and spreading shrub 2 to 10 feet tall, with longer white spines often 1 to II/2

inch long and with pods flattened and narrowed between the seeds.

It is widely distributed in the desert and desert grassland in southern New Mexico and southern and central Arizona.

MESQUITE (Prosopis juliflora (Sw.) DC-)

Varieties: Honey mesquite (P. juliflora var. glandidosa (Torr.)

Cockerell; botanical synonym, P. glandulosa Torr.). Western

honey mesquite (P. jvliflora var. torreyana L. Benson). Velvet

mesquite (P. juliflora var. velutina (Woot.) Sarg.; botanical

synonym, P. velutina Woot.).

Description : Spiny, spreading shrub branched from the base or

a small to medium-sized tree 20 to 50 feet tall with a trunk 1 to 4

feet in diameter and with spreading crown of crooked branches.

Twigs slightly zigzag, hairless (or in velvet mesquite densely shorthairy or velvety), with stout yellowish spines 14 to 1 inch long in

pairs at nodes, the nodes afterwards bearing short knotlike spurs

y4, to 1/2 inch in diameter. Leaves bipinnately compound, 3 to 8

inches long, with 1 or 2 pairs of primary divisions (pinnae), each

with 9 to 22 pairs of yellow-green leaflets, usually very narrow

and hairless (oblong and finely hairy in velvet mesquite). Flowers

in dense narrow clusters 2 to 3 inches long, yellow, fragrant, from

April to August. Pod 3 to 8 inches long, hairless (finely hairy in

velvet mesquite), not splitting open, with sweetish pulp. Bark

rough and thick, separating into long narrow strips, dark brown.

Wood hard and heavy, reddish brown with thin yellow sapwood.

Distribution: Common to abundant on sandy plains and sandhills and along stream valleys and washes, in short-grass, desert,

desert-grassland, and infrequently lower oak-woodland zones, from

slightly above sea level to 5,500 feet elevation. New Mexico: plains

of eastern and southern parts north to Tucumcari and Santa Rosa
66 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

and in Rio Grande drainage to Socorro, and west to Hidalgo County.

Arizona: widespread in southern, central, and northwestern parts

northward in drainages of Gila, Salt, Verde, Bill Williams, and

Virgin Rivers and up Colorado River to bottom of Grand Canyon.

Texas to Kansas and southeastern Colorado, west to southwestern

Utah, southern Nevada, and southern California. Also in West

Indies, Mexico, Central America, Venezuela, and Colombia.

The mesquites of southwestern United States are considered

here as a single species with three intergrading geographical varieties, following Benson and Darrow. Honey mesquite (var.

glandvlosa)y a shrub or tree on the short-grass plains west to

eastern New Mexico, is the variety with largest leaflets, 1 to 2V2

inches long and widely spaced about 1/2 inch apart. Western honey

mesquite (var. torreyana), usually shrubby or sometimes a small

tree characteristic of southwestern New Mexico deserts, western

Arizona, and southern California, has leaflets of intermediate size

V2 to % inch long spaced about ^4 inch apart. Velvet mesquite

(var. velutina) y usually a medium-sized tree found across southern

and central Arizona, has the smallest leaflets, 14. to V2 inch long

and closely spaced about Vg inch apart. Velvet mesquite is further distinguished by the twigs, leaflets, and pods finely shorthairy to velvety, while the other varieties are essentially hairless.

The leaves of velvet mesquite have 1 or 2 pairs of divisions (pinnae)

in about equal numbers, while leaves of the other varieties have

usually 1 pair. The typical Mexican and West Indian mesquite is

similar to velvet mesquite but is hairless and has leaves with generally 1 pair of pinnae.

Mesquite provides one of the best wood fuels in the desert. Even

the roots, which often are larger than the trunks and which penetrate to depths of 50 feet in areas with moist subsoils, are grubbed

up. Plants cut back to the ground will send up new sprouts from

the base. The wood is used also for fence posts and novelties. The

sweet pods are relished by livestock and were prepared into meal

and cakes as an important food of southwestern Indians. The flowers are a good source of honey.

Mesquites have created a serious problem in range management

by spreading greatly onto southwestern grasslands in recent years

following grazing. The hard seeds, which remain viable in the

soil many years, have been widely disseminated by livestock.

Methods of eradicating mesquite are being tested and applied in a

few places. In sandy soils of southern New Mexico, dunes often

form around shrubby mesquites, burying the plants except for a

hemispherical mass of branching tips.

FREMONT SCREWBEAN (Prosopis pubescens Benth.)

Also called screwbean mesquite, tornillo. Botanical synonyms:

P. odorata Torr. & Frém., Strombocarpa pubesceits (Benth.) A.

Gray, S. odorata (Torr. & Frém.) Torr.

Description: Spiny shrub or small tree to 20 feet tall and 1

foot in trunk diameter, or sometimes larger. Twigs usually grayhairy when young, with white or pale gray stout spines Ys to %

inch long, paired at nodes and united to base of leafstalks. Leaves
SOUTHWESTERN TREES 67

bipinnately compound, 1 to 3 inches long, with 1 or sometimes 2

pairs of primary divisions (pinnae), each with 5 to 8 pairs of

oblong, slightly hairy leaflets about % inch long. Flowers in usually

dense clusters 2 to 3 inches long, from May to August. Pod 1 to

IV2 inches long, less than i/4 inch in diameter, tightly coiled like

a large screw, brown, not splitting open, with sweetish pulp. Bark

separating in long fibrous strips, light brown or reddish. Wood

very hard, heavy, light brown.

Distribution : Common along streams and valleys in desert zone,

from slightly above sea level to 5,500 feet elevation. New Mexico :

southwestern part, north in Rio Grande valley to Socorro. Arizona :

southern and western parts, along larger valleys, from Cochise to

Yuma and Mohave Counties. From southwestern Texas weist and

northwest to southwestern Utah, southern Nevada, and southeastern California. Also in northern Mexico.

Easily recognized by the screwlike pods and often called tornillo,

which is Spanish for screw. The wood is used for fuel and fence

posts. The sweet pods were made into meal and cakes by the

Indians and can be chewed and eaten.

CALIFORNIA REDBUD {Cereis occidentalis Torr.)

Also called western redbud, Arizona redbud, Judas-tree. Botanical synonyms: C. occidentalis var. orbicutata (Greene)

Tidestr., C. arizonica Rose.

Description: Large shrub or small tree to 15 feet tall, with

many spreading branches and rounded crown. Twigs reddish

brown when young, becoming dark gray the second year, without

hairs. Leaves rounded, 2 to 4 inches long and broad, heart-shaped

at base and rounded at apex, edges without teeth, thick, dark

green above and paler beneath, usually hairless. Flowers appearing

on old twigs before the leaves, numerous and very showy, several

in a cluster, pealike, 1/2 to % inch long, purplish pink, in March

and April. Pods 2 to 3 inches long, flat, thin, brown or purplish.

Bark smooth, becoming slightly fissured, gray. Wood yellowish

brown with thin whitish sapwood.

Distribution : Rare and local, restricted to a few scattered localities in canyons and mountains in upper desert and woodland zones,

4,000 to 6,000 feet elevation; not in New Mexico. Arizona: Baboquivari Mountains (Pima County), Superstition Mountains (Pinal

County), Grand Canyon (Coconino County), and Pagumpa Springs

(Mohave County). Also in southern Utah, southern Nevada, and

California.

California redbud is common at Grand Canyon. It is worthy of

cultivation as an ornamental for the spectacular flowers which

cover the branches in early spring.

JERUSALEM-THORN (Parkinsonia aculeata L.)

Also called Mexican paloverde, horsebean, retama.

Description: Spiny, small or medium-sized tree to 40 feet tall

and 1 foot in trunk diameter, with smooth, yellow-green bark,

branches, and twigs, very open crown of spreading branches and

drooping twigs and '^streamers," appearing as if leafless most of
68 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

year. Twigs slightly zigzag, slender, with paired short spines at

nodes bordering a third, larger, brownish spine 1 to ll^ inch

long at end of the very short leaf axis. Leaves bipinnately compound but appearing as if pinnate, consisting of the short, spinetipped axis and 1 to 3 pairs of wiry but flattened, narrow, evergreen ''streamers" (pinnae) 8 to 20 inches long. Leaflets 25 to 30

pairs on a ''streamer," narrowly oblong, ^4 inch or less in length,

light green, soon falling. Flowers in loose clusters 3 to 8 inches

long, showy, about % inch across, golden yellow except that upper

petal is red-spotted and turns red in withering. Pod 2 to 4 inches

long, less than 1/2 inch in diameter, long-pointed, narrowed between

the few seeds. Bark smooth, thin, yellow green, at base of larger

trunks becoming scaly and brown. Wood hard and heavy.

Distribution: Rare and very local as a native tree in Arizona,

in foothills, canyons, and valleys of desert and desert grassland

zones, 3,000 to 4,500 feet elevation ; also extensively planted as an

ornamental tree and escaping. New Mexico: not native but reported to escape from cultivation in southern part. Arizona : native

in southwestern part, in foothills of Coyote and Baboquivari Mountains (Pima County) and at Horse Tanks in Castle Dome Mountains

(Yuma County) ; escaped from cultivation in Santa Cruz River

valley (Santa Cruz County) and other places. Native also in southern Texas and south through Mexico to Central America and

South America. Naturalized from Florida to Texas and California

and in tropical parts of the world.

Jerusalem-thorn is a popular, fast-growing, attractive tree

widely planted as an ornamental in warmer parts of the Southwest and in tropical countries. The word "Jerusalem" in this and

other plant names (such as Jerusalem-artichoke) does not refer

to the city in Palestine but is a corruption of girasol, meaning

"turning toward the sun.'*

YELLOW PALOVERDE {Cercidium microphyllum (Torr.)

Rose & lohnst.)

Also called foothill paloverde, littleleaf paloverde, littleleaf

horsebean. Botanical synonym : Parkinsonia microphylla Torr.

Description : Spiny small tree to 25 feet tall and 1 foot in trunk

diameter, with widely spreading, much-branched open crown, and

with smooth, yellow-green bark, branches, and twigs, leafless most

of the year. Short lateral twigs stiff and ending in stout spines.

Leaves few, bipinnately compound but apparently pinnately compound, % to 1 inch long, consisting of a very short axis and 1 pair

of primary divisions (pinnae, each bearing 4 to 7 pairs of very

small elliptical leaflets YQ inch or less in length, yellow-green,

slightly hairy, appearing in spring but soon shedding. Flowers

numerous and covering the tree, few in a cluster 1 inch long, about

1/4 inch across, pale yellow, about V2 inch in diameter, the upper

petal white or cream, in April and May. Pod 2 to 3 inches long,

about ^4 inch in diameter, cylindric, 1- to 3-seeded, narrowed between the seeds. Bark smooth, thin, yellow green, at base of larger

trunks becoming slightly rough and gray. Wood hard, heavy, dark
SOUTHWESTERN TREES 69

Jerusalem-thorn. Yellow paloverde. Blue paloverde

orange brown streaked with red, with thick light brown or yellow

sapwood.

Distribution: Abundant and characteristic tree on plains, foothills, and mountains in Arizona deserts, 500 to 4,000 feet elevation ;

not in New Mexico. Arizona : deserts of southern and central parts,

from Benson (Cochise County) and Coolidge Dam (Gila County)

west to southern Mohave County and Yuma County. Also in southeastern California (Whipple Mountains) and northwestern Mexico

(Sonora and Lower California).

Yellow paloverde, or "foothill paloverde," is a characteristic,

slowly growing tree of Arizona deserts, associated especially with

the saguaro. This species is commoner than blue paloverde and

grows on the widespread drier sites, while blue paloverde occurs

chiefly along drainages. Both species are leafless most of the year.

The Spanish common name **palo verde,*' meaning '*green tree,"

"green pole," or "green stick," refers to the distinctive smooth

green branches and twigs, which manufacture food in the absence

of leaves and with much less evaporation of water. The specific

names yellow paloverde and blue paloverde refer to the color shades

of the branches, twigs, and foliage. Yellow paloverde blossoms later

in the spring than blue paloverde and has smaller and paler yellow

flowers. Seeds of paloverdes were ground and used as food by the

Indians. The trees are grown as ornamentals.

BLUE PALOVERDE (Cercidium floridum Benth.)

Botanical synonyms: C. torreyanum (S. Wats.) Sarg., Parkinsonia torreyana (Benth.) S.Wats.

Description: Spiny, small tree to 30 feet in height and I14 feet

in trunk diameter, with widely spreading, very open crown and

with smooth, blue-green bark, branches, and twigs, leafless most

of the year. Twigs slightly zigzag, bearing a spine l^ inch or less

in length at each node. Leaves few and scattered, bipinnately compound, 1 inch long, with 1 pair of primary divisions (pinnae), each

bearing 2 or 3 pairs of oblong leaflets about 14 inch long, pale bluegreen and hairless at maturity, appearing in spring but soon shedding. Flowers numerous over the tree, 4 or 5 in a cluster 1 to 2
70 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

inches long, about % inch across, bright yellow, the upper petal

with a few red spots but not turning red in withering, in late March

or April (sometimes also from August to October). Pod 3 to 4

inches long, flattened. Bark smooth, thin, blue-green, at base of

larger trunks becoming scaly and brown. Wood soft, heavy, light

brown with light yellow sapwood.

Distribution : Common and characteristic tree along washes and

valleys and sometimes on slopes, desert and desert grassland, from

slightly above sea level to 4,000 feet elevation ; not in New Mexico.

Arizona: deserts of southern and central parts, from San Pedro

River in Cochise County and Gila River at Duncan (Greenlee

County), northwest to Gila, southern Yavapai, southern Mohave

Counties and southwest to Yuma County. Also in southeastern

California and northwestern Mexico (Sonora and Lower California) .

Blue paloverde is very showy when in blossom, becoming a mass

of bright yellow flowers.

MESCALBEAN (Sophora secundiflora (Ortega) Lag.)

Also called frijolito, mescalbean sophora, coralbean, goat-bean.

Botanical synonym : Broussonetia secundifloTa Ortega.

Description : Evergreen shrub usually 3 to 5 feet tall or rarely

small tree to 15 feet tall and 4 inches in trunk diameter, much

branched. Twigs densely white-hairy when young. Leaves pinnately compound, 3 to 6 inches long. Leaflets 7 to 13, elliptical,

% to 2 inches long, rounded or slightly notched at apex, leathery,

shiny dark green above, paler and hairless or nearly so beneath.

Flowers in dense dropping clusters 2 to 3 inches long, large and

showy, % to 1 inch long, pealike, purple, fragrant, in April. Pod

1 to 4 inches or more in length, 1/2 inch in diameter, finely whitehairy, hard and thick-walled, narrowed between the seeds, with 1

to 4 or more rounded scarlet seeds 1/2 inch long. Wood hard, very

heavy, orange with red streaks and with thick yellow sapwood.

Distribution: Local in canyons and limestone cliffs of foothills

and mountains, oak woodland zone, 4,500 to 6,500 feet elevation;

not in Arizona. New Mexico: known only from Guadalupe Mountains in southeastern part. Also in Texas and northeastern

Mexico.

This attractive shrub with beautiful blue flowers and conspicuous

red seeds is reported to be cultivated in the southern States. The

seeds are poisonous. One might be sufficient to kill an adult. Also,

the foliage is thought to be toxic to livestock.

KIDNEYWOOD {Eysenhardtia polystachyo (Ortega) Sarg.)

Botanical synonym: E. orthocarpa (A. Gray) S. Wats.

Description: Shrub or sometimes a small tree to 20 feet in.

height, with a short trunk 6 inches or more in diameter and many

slender branches. Twigs gray or brown, hairy when young. Leaves

pinnately compound, 2 to 5 inches long, resinous and gland-dotted,

with disagreeable odor. Leaflets mostly 10 to 23 pairs with the last

unpaired, narrowly oblong, % to % inch long, rounded or slightly

notched at apex, thick, pale gray green, finely hairy, with con-
SOUTHWESTERN TREES 71

Kidneywood. Smokethorn. New Mexican locust. Tesota.

spicuous brown dots beneath. Flowers numerous, crowded in clusters 3 to 4 inches long, stalkless and pointed downward, nearly Vè

inch long, white, with minute brown dots, from May to August.

Pods many, 1/2 inch long, flat and slightly curved, brown, hanging

down, 1-seeded. Bark thin, scaly and peeling off, light gray. Wood

heavy, hard, light reddish brown with thin yellow sapwood.

Distribution: Common on dry hillsides and rocky canyons of

mountains, upper desert grassland, and lower oak woodland, 3,500

to 5,000 feet elevation, in Mexican border region. New Mexico:

extreme southwestern comer, in southern Hidalgo County. Arizona: mountains of southeastern part, from Cochise County west

to Final County and Baboquivari Mountains in Pima County. Also

in northern and central Mexico.

The resinous foliage is readily browsed by livestock and wildlife.

Water in which the heartwood has been soaked has a peculiar

fluorescence and formerly was used for kidney and bladder diseases

under the name lignum nephriticum, A dye has been made from

the wood also.

SMOKETHORN (Dalea spinosa A. Gray)

Also called smoketree, indigobush, smokethorn dalea.

Description : Small, compact, spiny tree or large shrub to 20 feet

tall, with a short, branching trunk up to 11/^ feet in diameter and

with compact mass of smoky gray or silvery branches and spiny

twigs, leafless most of the year. Twigs gray or silvery with dense

pressed hairs, with brown gland dots, ending in sharp spines.

Leaves few, reverse lance-shaped, % to 1 inch long, gland-dotted,

remaining only a few weeks and falling before flowering. Flowers

few in a cluster, pealike, 1/2 inch long, dark purple, with brown

gland dots, in April and May. Pods egg-shaped, % iiich ^on^, gland

dotted, with 1 or 2 seeds. Bark of trunk thin, fissured and scaly,

dark gray brown. Wood soft, lightweight, dark brown with whitish

sapwood.

Distribution : Washes in the desert at low, frost-free elevations

from slightly above sea level to 1,000 feet (rarely 1,500 feet) ; not

in New Mexico. Arizona : deserts of southwestern part, from west-
72 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

ern Pima and western Maricopa Counties west to Yuma and southwestern Mohave Counties. Also in southeastern California and in

northwestern Mexico (Lower California and Sonora).

Smokethorn, or "smoketree," derives its common names from

the smoky gray color of the compact, leafless branches and twigs,

as seen from a distance.

NEW MEXICAN LOCUST {Robinia neo-mexicana A. Gray)

Also called southwestern locust. Botanical synonyms: R. neO"

mexiccma var. luxurians Dieck, R. neo-mexicana var. subvelutina

(Rydb.) Kearney & Peebles.

Description : Spiny shrub or small tree up to 25 feet tall and 8

inches in trunk diameter. Twigs with brownish, glandular hairs

when young, with brown or reddish, stout spines l^ to 1/2 inch

long in pairs at nodes. Leaves pinnately compound, 6 to 12 inches

long. Leaflets 15 to 21, elliptical, 1/2 to IV2 inches long, bristletipped, thin, pale blue green, hairy when young but becoming nearly

hairless. Flowers many in large clusters, large and showy, about

% inch long, pealike, purplish pink, fragrant, from May to August.

Pod 2V2 to 41/^ inches long, flat, thin, reddish brown, bristly hairy

and usually glandular. Bark furrowed and scaly, thin, light brown

or gray. Wood very hard, heavy, yellow streaked with brown.

Distribution : Common to abundant in canyons and mountains,

often forming almost pure thickets on north-facing slopes and also

associated with Gambel oak, ponderosa pine forest and upper

pinyon-juniper woodland, 4,000 to 8,500 feet elevation. New

Mexico: widely distributed in mountains of western two-thirds

and northeastern corner, from Sacramento, White, and Sandia

Mountains and Union County, westward. Arizona: northeastern

half, from Cochise and Pima Counties northwest to Hualpai Mountains and north rim of Grand Canyon. Also in northern Mexico.

Occasionally propagated as an ornamental and for erosion control

and establishing itself from cultivation. Because of rapid growth

and the tendencies to form thickets and to sprout from the horizontal roots, the plants are of special value in reducing erosion.

TESOTA (Olneya tesota A. Gray)

Also called desert ironwood, palo fierro, palo de hierro.

Description: Spiny evergreen tree to 30 feet in height, with a

short trunk to 3 feet in diameter with symmetrical, widely spreading crown. Twigs green or gray and densely hairy when young,

becoming light brown, with sharp spines about 14 inch long in

pairs at nodes. Leaves in dense clusters, pinnately compound, 1 to

214 inches long, generally evergreen. Leaflets 2 to 10 pairs, oblong

or obovate, % to % inches long, usually rounded at ends, thick,

blue-green, finely hairy with pressed hairs. Flowers in short clusters, pealike, i/è inch long, purplish, in May and June. Pod 2 to 2^^

inches long, brown, glandular hairy, thick-walled, with few seeds.

Bark thin, smoothish, gray, on large trunks becoming much fissured

and shreddy. Wood very hard, very heavy, dark brown with thin

yellow sapwood.
SOUTHWESTERN TREES 73

Distribution: Common and characteristic desert tree of sandy

washes in foothills at lower, warmer elevations from slightly above

sea level to 2,500 feet ; not in New Mexico. Arizona : southwestern

quarter, from Tucson and lower Verde River valley (Maricopa

County) westward to southern Mohave County and Yuma County.

Also in southeastern California and in northwestern Mexico (Lower

California and Sonora).

The wood is so hard that it dulls tools. In weight, it is perhaps

second only to leadwood (southern Florida), of all trees native in

the United States. It is easily polished and is used for novelties,

such as bowls and small boxes. Many trees have been cut for fuel.

As tesota, or *'ironwood," is limited to warm areas, it is regarded as

an indicator in the selection of sites for citrus orchards. The seeds,

which are produced in quantities, are edible when roasted and have

been used for food by Indians and many other residents.

SOUTHWESTERN CORALBEAN (Erythrina flabelliformis

Kearney)

Also called western coralbean, chilicote, Indian-bean.

Description: Spiny shrub or sometimes a small tree to 15 feet

tall and 10 inches in diameter at base, leafless except in summer.

Twigs thick, brittle, with many scattered, single or paired, short,

hooked spines. Leaves pinnately compound, with spiny leafstalk

and 3 leaflets, broadly triangular with rounded angles or fanshaped, 1^4 to 3 inches long and 2 to 4 inches broad, gray-green,

produced in summer. Flowers several in a cluster, large and showy,

V/2 to 2 inches long and only 14 inch broad, bright red or scarlet,

in spring and sometimes also late summer. Pod large, 6 to 10 inches

long and V2 to % inch broad, thick-walled, with several large, bright

red seeds about 1/2 inch long. Bark light brown with longitudinal

white lines. Wood very brittle.

Distribution : Fairly common on warm, dry rocky slopes, washes,

and canyons of foothills and mountains in upper desert, desert

grassland, and oak woodland zones, 3,000 to 5,000 feet elevation,

in the Mexican border region. New Mexico : southwestern corner,

in Hidalgo and Grant Counties. Arizona: southeastern part, from

Cochise County west to Santa Catalina Mountains and Baboquivari

Mountains in Pima County. Also in northern and northwestern

Mexico.

Usually shrubby with branches freezing back in severe winters.

The scarlet seeds are poisonous. They are used in making novelties

and necklaces and formerly by Indians as a charm.

Rue Family (Rutaceae)

PALE HOPTREE {Ptelea pallida Greene)

Botanical synonym : P. angustifolia auth., not Benth.

Description: Shrub or small tree to 10 feet or more in height,

with strong, lemon-scented odor of crushed foliage and twigs.

Twigs straw-colored to greenish yellow. Leaves compound, long-
74 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

stalked, with 3 mostly lance-shaped leaflets 1 to 2 inches long, longpointed, edges slightly wavy-toothed or without teeth, thick and

ñrm, with many minute gland dots, yellow-green and often shiny

above, beneath paler and hairless or sparsely hairy. Flowers in

branching clusters, partly of separate sexes, small, greenish yellow,

in May. Fruit disk-shaped, flat, light brown, 2- or 3-seeded, surrounded by a broad wing % inch in diameter.

Distribution: Canyons, plateaus, and mountains, pinyon-juniper

woodland and upper part of desert zone, 2,000 to 7,000 feet elevation. New Mexico : mountains in southern part, from Oregon Mountains westward. Arizona : central and northern parts, from Yavapai

County to Coconino and Mohave Counties; especially common at

Grand Canyon. Also in southwestern Texas.

NARROWLEAF HOPTREE {Ptelea angustifolia Benth.)

Botanical synonym: P. angiistifolia var. cognata (Greene)

Kearney & Peebles.

Description : Shrub or small tree to 13 feet or more in height,

with strong, unpleasant odor in crushed foliage and twigs. Twigs

brown or dark purple. Leaves compound, long-stalked, with 3

mostly ovate leaflets 1 to 3 inches long, long-pointed, edges slightly

wavy-toothed or without teeth, thin, with many minute gland dots,

green or blue-green but not shiny, beneath often with a bloom and

soft-hairy or nearly hairless. Flowers in branching clusters, partly

of separate sexes, small, greenish yellow, from March to June.

Fruit disk-shaped, flat, light brown, 2- or 3-seeded, surrounded by

a broad wing % inch in diameter. Bark smooth, brownish gray.

Distribution : Mostly in canyons, ponderosa pine forest and pinyon-juniper woodland, 3,500 to 8,500 feet elevation. New Mexico:

widely distributed in mountains of western two-thirds, from Organ

Mountains, White Mountains and Sandia Mountains north and west.

Arizona: northeastern half, from Cochise and Apache Counties

west to Hualpai Mountains and to Pima County, Texas to Colorado,

Arizona, and California, and south to Mexico.

Ailanthus Family (Simaroubaceae)

HOLACANTHA {Holacantha emoryi A. Gray)

Also called cruciñxion-thorn, corona de Cristo.

Description : Very spiny shrub or small tree to 12 feet in height,

with numerous stiff, tangled branches and twigs, leafless most of

the year. Twigs short, stout, Vè to 14 i^^ch in diameter, finely hairy

when young, ending in sharp spines. Leaves scalelike, soon shedding. Flowers male and female on different plants (dioecious), in

dense many-flowered clusters, small, 14 to % inch in diameter,

greenish yellow, in June and July. Fruit a ring of 5 to 10 flattened,

1-seeded segments l^ inch long, the clusters of old fruits remaining

attached for years. Bark smooth.
SOUTHWESTERN TREES 75

Southwestern Pale hoptree.

coralbean.

Narrowleaf hoptree. Holacantha.

Distribution: Frequent in desert valleys on clay soils but also

on sand dunes, 500 to 2,000 feet elevation; not in New Mexico.

Arizona: southwestern quarter, from western Pima County and

Gila River at Florence (Final County) west in Maricopa and Yuma

Counties, especially in lower Gila and Colorado River drainages.

Also in southeastern California and in Sonora, Mexico.

Holacantha (Latin for allthorn) is one of the three very spiny,

much branched, shrubby species known in the Southwest as **crucifixion-thorns/' The others are canotia and allthorn. Holacantha

is the only native southwestern representative of the ailanthus

family (Simaroubaceae), which is mostly tropical.

Ailanthus (AUanthiis altissima (Mill.) Swingle; also called

tree-of-heaven and tree-of-heaven ailanthus), a native tree of

China belonging to the same family, is planted as a shade tree in

southern New Mexico and Arizona. It occasionally escapes from

cultivation in the Southwest, spreading by sprouts from the roots,

and may in time become naturalized here as in many other parts

of the United States. This medium-sized, coarsely branched tree

has large pinnately compound leaves li/^ to 2^/^ feet long, with 13

to 25 broadly lance-shaped, long-pointed leaflets 3 to 5 inches long,

each with 2 to 4 teeth near base.

Bursera Family (Burseraceae)

FRAGRANT BURSERA (Bursera odorata T. S. Brandegee)

Description: Strongly aromatic shrub or small tree to 15 feet

tall. Leaves pinnately compound, 2 to 4 inches long, with winged

axis, aromatic, with odor of tangerine peel when crushed. Leaflets

5 to 11, lance-shaped, y^ to IV2 inches long, edges without teeth,

hairless. Flowers several in a cluster below a group of new leaves

at end of a short side twig, in July. Fruits 3-angled, less than %

inch long, gray, 1-seeded, splitting into 3 parts. Bark of branches

gray brown, on old trunks peeling off in large, thin, papery sheets.
76 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Distribution : Rare at one Arizona locality near Mexican border,

on dry limestone cliffs in desert mountains, 4,000 feet elevation;

not in New Mexico. Arizona: southern part, known only from

western foothills of Baboquivari Mountains near Fresnal (Pima

County). Also in Mexico.

This Mexican desert tree has been found in the United States

at only one place, where the few living plants appear to be relics

from a more favorable period.

ELEPHANTTREE (Bursera mîcrophylla A. Gray)

Also called torote, copal, elephant bursera.

Description: Strongly aromatic shrub or small tree to 20 feet

tall, with relatively thick, swollen trunk to 1 foot in diameter, short

and sharply tapering, with stout, crooked, tapering branches, and

with widely spreading, rounded, open crown of thin foliage. Twigs

reddish brown, hairless. Leaves pinnately compound, 1 to l^A

inches long, with winged axis, aromatic. Leaflets, 15 to 30, small,

narrowly oblong leaflets about 1/4 inch long, edges without teeth,

hairless. Flowers single or 2 or 3 at a node, short-stalked, small,

less than i^ inch long, whitish, partly of separate sexes, in July.

Fruits 3-angled, ^4 inch long, red, 1-seeded, splitting into 3 parts,

aromatic. Bark of trunk and branches papery and peeling off in

thin flakes, white on outside, the next thin layers green, and the

inner thick layers red and corky. Wood hard, pale yellow.

Distribution : Common locally on rocky slopes of very arid desert

mountains, 1,000 to 2,500 feet elevation ; not in New Mexico. Arizona: mountains of southwestern part, south of Gila River, from

western Pima County, western Pinal County and Salt River Mountains (Maricopa County) west to Gila and Tinajas Altas Mountains

in southern Yuma County. Also at one locality in southeastern

California and in Mexico.

The common name is from the stout, tapering branches which

resemble an elephant's trunk. The trees are not resistant to cold

and are killed back when young.

Spurge Family (Euphorbiaceae)

CASTOR-BEAN (Ricinus communis L.)

Description: Herb, shrub, or in warm regions a small tree to

15 feet or more in height, with hollow stems and leafstalks. Leaves

very long-stalked, very large, nearly circular, 1 foot or more in

diameter, with usually 7 to 10 fingerlike (palmate) lobes surrounding the leafstalk, edges saw-toothed, thick, often reddish or purplish tinged. Flowers in large branched clusters at tops of branches,

female flowers above and male flowers below. Seed capsule % to 1

inch in diameter, spiny, 3-celled, splitting open, with 3 large, poisonous seeds i/^ to % inch long. Bark smooth, light gray.

Distribution: Escaping from cultivation and naturalized along

washes and streams in desert in Arizona but not New Mexico. Ari-
SOUTHWESTERN TREES 77

Fragrant bursera. Elephanttree. Castor-bean. Jumping-bean sapium.

zona: naturalized near Superior (Final County), Fort Verde (Yavapai County), and perhaps elsewhere. Probably native of Africa

but widely cultivated and naturalized over the world, escaping from

cultivation in warmer parts of the United States.

Castor-bean is extensively planted for ornament, as a large annual herb in temperate regions and as a perennial shrub or small

tree in regions with mild winters. The raw seeds are very poisonous. It is reported that eating three seeds may cause death. Other

parts of the plant also contain the toxic principle, which is destroyed by heat. Castor oil, extracted from the seeds, is used in

medicine and as a lubricant.

JUMPING-BEAN SAPIUM (Sapium biloculare (S. Wats.) Pax)

Also called Mexican jumping-bean.

Description: Tall shrub or small tree to 15 feet in height, with

milky juice. Leaves lance-shaped, % to 2i/i inches long, longpointed, edges finely saw-toothed, leathery, without hairs. Flowers

in narrow zigzag clusters 1 to 2^4 inches long at ends of twigs,

stalkless, fragrant male flowers above and 1 or 2 female flowers

at base, from March to November. Seed capsule 2-lobed, nearly

1/^ inch broad, splitting open, with 2 nearly spherical, mottled

brownish gray seeds about i/^ inch long.

Distribution : Common locally in rocky slopes and sandy washes

of desert, 800 to 2,500 feet elevation ; not in New Mexico. Arizona :

southwestern part, south of Gila River, from western Pima County

and near Gila Bend (southern Maricopa County) west to Tinajas

Altas (Yuma County). Also in northwestern Mexico (Sonora and

Lower California).

This species produces Mexican jumping-beans, though it is not

the important, widely distributed Mexican jumping-bean. The

larva of a small moth, which often infests the seeds, by its movements causes a seed to move and roll slightly. The milky juice is

poisonous. It has been used as a fish poison and by Indians to

poison their arrows. A very small amount of this juice rubbed into

the eyes accidentally after a plant is handled will cause extreme

pain for hours.
78 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Cashew Family (Anacardiaceae)

SUGAR SUMAC {Rhus ovata S. Wats.)

Also called sugarbush, mountain-laurel.

Description : Evergreen shrub or small tree to 15 feet in height

and 5 inches in trunk diameter, with rounded crown. Leaves ovate

1 Va to 3^4 inches long, short-pointed, rounded at base, edges without teeth, thick and leathery, not flat but curved upward at midrib,

shiny light green on both sides, hairless. Flowers small in crowded

clusters 2 inches long at tips of twigs, about l^ inch across, pink

or reddish in buds but cream-colored when open, in April. Fruit

reddish, hairy, sweetish. Bark rough, shaggy and very scaly, gray

brown. Wood light brown.

Distribution: Common on mountain slopes in chaparral, 3,000

to 5,000 feet elevation ; not in New Mexico. Arizona: Gila, eastern

Maricopa, southern Coconino (Oak Creek Canyon), and Yavapai

Counties and on Hualpai Mountains. Also in southern California

and in northern Lower California, Mexico.

This attractive broadleaf evergreen is one of several shrubby

species of the chaparral vegetation in southern California which reappear in the same zone in the mountains of central Arizona. In

California it is planted for erosion control and landscaping in mountains and as an ornamental. The common name refers to the sweetish, edible fruit coats, which were used as sugar by the Indians.

KEARNEY SUMAC {Rhus kearneyi Barkley)

Description: Evergreen large shrub or small tree to 18 feet in

height. Leaves oblong, 1 to 2^4 inches long, rounded or bluntpointed at apex, edges without teeth but rolled under, very leathery,

almost without hairs. Flowers small in short, crowded clusters at

tips of twigs, less than 14 inch across, whitish. Fruit oblong, %

inch long, slightly flattened, reddish and hairy.

Distribution: Known from a single locality on dry slopes in

desert, 1,000 to 1,500 feet elevation, on Mexican border; not in

New Mexico. Arizona: known only from Tinajas Altas Mountains,

southern Yuma County, where this species was discovered.

Kearney sumac is named for Thomas H. Kearney, botanist of

the United States Department of Agriculture and co-author of

Flowering Plants and Ferns of Arizona.

MEARNS SUMAC {Rhus choriophylla Wool. & StandL)

Description : Evergreen shrub usually less than 7 feet tall, rarely

a small tree 15 feet in height and 3 inches in trunk diameter, with

relatively few branches. Leaves pinnately compound, 2 to 3 inches

long. Leaflets 3 or 5, ovate, 1 to 2 inches long, short-pointed, edges

without teeth, thick and leathery, shiny green above and dull

green below, slightly hairy. Flowers small, several in cluster, about

Vs inch long, whitish, in August and September. Fruit ^4 inch

long, reddish, hairy. Bark scaly and shaggy, gray.
SOUTHWESTERN TREES 79

Kearney sumac, Mearns sumac. Canotia.

Distribution : Dry rocky slopes especially on limestone, canyons

and mountains in oak woodland, 4,000 to 6,000 feet elevation. New

Mexico : mountains of southern part, from Sacramento Mountains,

San Andres Mountains, and Organ Mountains west to Hidalgo

County. Arizona: mountains of southeastern corner, in Cochise,

Santa Cruz, Pima, and Final Counties. Also in Sonora, Mexico.

Previously known only as a shrub, Mearns sumac has been found

by Leslie N. Goodding as a small tree in Santa Cruz County, Ariz.

This species was discovered by Edgar A. Mearns (1856-1916),

American naturalist and Army surgeon, who made very large plant

and animal collections along the Mexican boundary from 1891 to

1894.

Bittersweet Family (Celastraceae)

CANOTIA {Canotia holacantha TorrO

Also called crucifixion-thorn.

Description : Spiny shrub or small tree to 18 feet in height, with

short trunk up to 1 foot in diameter, with many flexible, upright,

yellowish green, rushlike branches and twigs in broomlike masses,

leafless most of the year and resembling paloverdes. Twigs i/g to Î46

inch in diameter, inconspicuously grooved, hairless, with small

black rings at base where forked, partly ending in spines or dead

tips. Flowers 3 to 7 in small clusters along the twigs, nearly l^

inch in diameter, greenish white, May to August. Fruit a hard,

egg-shaped, long-pointed capsule, % inch or more in length, reddish

brown, 5-celled and splitting open along 10 lines, seeds single or

paired and winged. Bark on branches smooth and yellow green,

at base fissured, becoming rough and slightly shreddy, gray.

Distribution: Common or abundant locally on dry slopes and

hillsides in upper desert and lower chaparral, 2,000 to 5,000 feet

elevation; not in New Mexico. Arizona: chiefly in central and

western parts, from Graham and southern Navajo Counties west to

southern Coconino (Oak Creek Canyon), Yavapai (Verde River
80 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

valley and southern part), Mohave, and Yuma Counties ; at Havasu

Canyon near Grand Canyon. Also at Rainbow Bridge Canyon,

southern Utah.

Canotia resembles the paloverdes in its yellowish green, leafless

branches and twigs which are more crowded, upright, and in broomlike masses. It replaces paloverdes as a common desert tree in the

northern part of its range and is the commonest of the three spiny,

much-branched shrubby species called "crucifixion-thorns."

Maple Family (Aceraceae)

INLAND BOXELDER (Acer negundo L. var. interius (Britton)

Sarg.)

Also called boxelder, Rocky Mountain boxelder. Botanical

synonyms: A. negundo var. arizonicum Sarg., Negundo interius

(Britton) Rydb.

Description: Medium-sized tree to 50 feet in height and 2%

feet in trunk diameter, with broad, rounded crown. Twigs greenish,

usually finely and densely hairy or hairless and covered with a

bloom. Leaves paired, long-stalked, pinnately compound, about 6

inches long, with 3 or sometimes 5 leaflets, the end leaflet longstalked. Leaflets ovate, 2 to 4 inches long, long-pointed, coarsely

saw-toothed, usually thick, slightly hairy beneath or nearly hairless.

Flowers male and female on different trees (dioecious), in small

several-flowered clusters opening before or with the leaves, very

small, yellow-green, in April. Fruits paired, clustered, long-winged

"keys" IV2 to 2 inches long. Bark with many narrow fissures and

ridges, light gray-brown, on large trunks becoming deeply furrowed. Wood soft, lightweight, whitish or pale yellow.

Distribution: Common along streams, chiefly in mountains, oak

woodland and ponderosa pine forest zone, 4,000 to 8,000 feet elevation. New Mexico: widely distributed in high mountains of western two-thirds and northeastern comer, from White Mountains,

Sangre de Cristo Range, and Union County westward. Arizona:

high mountains and plateaus across the State except in southwest

quarter, from Cochise to Apache County and west to Mohave and

Pima Counties. Boxelder (Acer negundo L.), including a few geographical varieties, has a broad range from Massachusetts to Minnesota and Alberta, south to California, Texas., and Florida. Inland

boxelder is a variety of the interior, from New Mexico to Missouri,

north to Manitoba and Alberta, and south to Arizona.

Inland boxelder has thicker and more hairy leaves than the

typical form of boxelder in eastern United States. It is a rapidly

growing, short-lived tree often planted for shade where water is

available and has become naturalized locally.

ROCKY MOUNTAIN MAPLE (Acer glabrum Torr.)

Also called dwarf maple. Botanical synonyms : A, neomexicanum

Greene, A. glabrum var. neomexicanum (Greene) Kearney &

Peebles.
SOUTHWESTERN TREES 81

Inland boxelder. Rocky Mountain Bigtooth maple. Western soapberry,

maple.

Description : Shrub or sometimes small tree to 25 feet in height

and 1 foot in trunk diameter. Twigs reddish brown and without

hairs. Leaves paired, 3 to 5 inches long, with leafstalks long and

often red, simple or of 3 leaflets. Leaf blades heart-shaped, 3- or 5-

lobed, lobes sharply short-pointed, edges doubly saw-toothed, or

some or all deeply divided into 3 lance-shaped leaflets, shiny dark

green above and paler beneath, hairless, turning red in autumn.

Flowers male and female usually on different trees (dioecious), in

few-flowered terminal clusters, small, greenish yellow, in May and

June. Fruits paired, clustered, long-winged "keys," about % inch

long, reddish when immature but turning brown. Bark smooth,

thin, gray or brown. Wood hard, heavy, light brown.

Distribution: Moist soil and along streams in high mountains,

ponderosa pine, Douglas-fir, and spruce-fir forests, 7,000 to 9,000

feet elevation. New Mexico : high mountains of western two-thirds

and northeastern corner, from Sacramento Mountains, Sangre de

Cristo Range, and Union County westward. Arizona: high mountains and plateaus in northeastern half, from Cochise County northwest to north rim of Grand Canyon. Rocky Mountain maple including geographical varieties ranges from New Mexico north to Montana, Alberta, and southern Alaska, south to California and Arizona. The typical form described here is distributed from New

Mexico north to Black Hills and Montana, and south to California

and Arizona.

BIGTOOTH MAPLE (Acer grandidentatum Null.)

Also called western sugar maple. Botanical synonyms: A.

brachypterum Woot. & Standl., A. grandidentatum var. brachypte^vim (Woot. & Standl.) Palmer.

Description: Small to medium-sized tree to 50 feet tall and 1

foot in trunk diameter, with spreading, rounded crown. Twigs

bright red and without hairs. Leaves paired, long-stalked, heartshaped, 2 to 5 inches long and broad, 3-lobed, the lobes broad, bluntpointed, and with few large blunt teeth or small lobes, thick and

firm, shiny dark green above, beneath paler and usually finely
82 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

hairy, turning yellow or red in autumn. Flowers male and female

on the same tree in several-flowered clusters, small, about 14 inch

long, yellow, in April. Fruits paired, clustered, long-winged *'keys"

1 inch or less in length, greenish. Bark smoothish or scaly, thin,

gray or dark brown. Wood hard, heavy, brown or whitish.

Distribution: Fairly common in moist soil in canyons of high

mountains and plateaus, ponderosa pine forest, 4,700 to 7,000 feet

elevation. New Mexico: high mountains of southern part, from

Sacramento and White Mountains west to Black Range and San

Luis Mountains (Hidalgo County). Arizona: high mountains and

plateaus over the State, except in northeastern and southwestern

parts, Cochise and Greenlee Counties west to Oak Creek Canyon

and Grand Canyon (Coconino County), Hualpai Mountains, and

Pima County. Southwestern Texas and New Mexico, north to Montana and Idaho, and south to Arizona ; also in Wichita Mountains

of southwestern Oklahoma. Northern Mexico.

Bigtooth maple is related to sugar maple of eastern United States

and has been used as a source of maple sugar. The wood makes

good fuel.

Soapberry Family (Sapîndaceae)

WESTERN SOAPBERRY {Sapindus drummondi Hook. & Am.)

Also called wild china-tree, cherioni, jaboncillo. Botanical

synonym: S. saponaria L. var. drummondi (Hook. & Arn.) L.

Benson.

Description: Small tree to 25 feet tall and 1 foot in trunk diameter or a large spreading shrub. Twigs yellow green, finely hairy.

Leaves pinnately compound, 5 to 8 inches long, with 13 to 19 leaflets.

Leaflets lance-shaped, l^/^ to 4 inches long, one-sided, long-pointed,

edges not toothed, leathery, pale yellow green, hairless above and

slightly hairy beneath. Flowers many in large terminal clusters

6 to 9 inches long, from May to August. Fruits yellow, translucent,

berrylike, l^ inch in diameter, leathery, 1-seeded, remaining on the

twigs until spring. Bark smoothish or fissured and scaly, yellow

gray. Wood heavy, yellowish.

Distribution: Along streams and canyons, in plains and mountains, plains grassland, upper desert, desert grassland, and oak

woodland, 2,400 to 6,000 feet elevation. New Mexico: eastern and

southern parts, eastern border from Union County southward, west

through Roswell and Organ Mountains and north in Rio Grande

drainage to Albuquerque and west to Gila River drainage. Arizona :

southeastern and central parts, from Cochise County west to Santa

Cruz and Pima Counties and northwest below Mogollón Rim to

southern Coconino and Yavapai Counties; also near Hackberry

(Mohave County). Louisiana to Missouri, west to southern Colorado, and south to Arizona, Texas, and northern Mexico.

The fruits are poisonous. The foliage is unpalatable and perhaps

toxic to livestock. As the common name indicates, the fruits contain relatively high percentages of the alkaloid saponin and have

been used for soap in washing clothes.
SOUTHWESTERN TREES 83

Buckthorn Family (Rhamnaceae)

LOTEWOOD CONDALIA (Condalia obtusifolia (Hook.) Weberb.)

Also called lotebush, white crucillo, gray-thorn. Botanical

synonyms: C lycioides (A. Gray) Weberb., Zizyphits lycioides A.

Gray. Includes C. lycioides var. canescens (A. Gray) Trel.

Description : Spiny, much-branched shrub 3 to 8 feet tall, rarely

10 feet tall with a trunk 4 inches in diameter or larger. Twigs

numerous and widely spreading at right angles, 1 to 4 inches long,

light gray, hairless or in a variety densely short-hairy, ending in

sharp spines. Leaves small elliptical to ovate, % to % inch long

and 14 i^ich broad, hairless or in a variety densely short-hairy,

pale green. Flowers several in a slightly stalked cluster in leaf

axil, small, less than i/g inch long, whitish green. Fruit berrylike,

more than l^ inch in diameter, blue black with a bloom, juicy and

sweet, 1-seeded.

Distribution: Common, often forming thickets, on plains and

mesas in desert and desert grassland, 1,000 to 5,000 feet elevation.

New Mexico : southwestern part, from Organ Mountains north in

Rio Grande drainage to Socorro County and west to Hidalgo County.

Arizona : widespread in deserts of southern and central parts from

Cochise and Greenlee Counties to Yavapai and Mohave Counties

and Grand Canyon south to Yuma County. From central Texas to

southeastern California and northern Mexico.

This shrubby species rarely becomes a small tree in Arizona and

California and is here included as a tree. The variety in Arizona

(except in southeastern Cochise County), California, and adjacent

Mexico, shown at left in drawing, has densely short-hairy twigs

and leaves.

BITTER CONDALIA (Condalia globosa lohnst.)

Botanical synonym : C. globosa var. pubescejis Johnst.

Description: Spiny large shrub or small tree as much as 15 to

20 feet tall and 1 foot or more in trunk diameter, with broad crown

of tangled spreading branches. Twigs stiif, light gray or brown,

many ending in sharp spines. Leaves relatively few% not crowded,

single or clustered, very small, oblong but narrowed toward base,

l^ to % inch long, edges not toothed, usually densely and finely

hairy. Flowers 1 or 2 in leaf axils, small. Fruit berrylike, almost 14

inch in diameter, on stalks about the same length, black, juicy, very

bitter, 1-seeded. Bark much fissured and becoming shreddy, brownish gray.

Distribution: Dry sandy plains and along washes in desert, 1,000

to 2,500 feet elevation ; not in New Mexico. Arizona : southwestern

part in Growler and Ajo Mountains and Sierra Blanca in western

Pima County and Kofa and Castle Dome Mountains in Yuma

County. Also in northwestern Mexico (Sonora and Lower California) .
84 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Originally described in 1924 from Lower California, Mexico, as

a shrub 4 to 8 feet tall, bitter condalia becomes a small tree in

southwestern Arizona and thus represents an addition to the

native trees of the United States.

HOLLYLEAF BUCKTHORN {Rhamnus crocea Nutt. van ilicifoUa

(Kellogg) Greene)

Also called hoUyleaf redberry buckthorn.

Description : Evergreen shrub or small tree to 15 feet in height,

with spreading branches. Leaves hollylike, oval to nearly round,

% to 114 inches long, rounded at apex and base, edges spinytoothed, leathery, shiny yellow-green above, beneatla yellow-green

or paler and hairless or nearly so. Flowers usually male and female

on different plants, few in small clusters in leaf axils, small, about

% inch long, yellow-green, from March to May. Berries bright red,

V4. inch in diameter, juicy, usually 2-seeded. Bark slightly rough

and fissured, dark gray. Wood light brown.

Distribution: Common in mountains in chaparral and lower

ponderosa pine forest, 3,000 to 7,000 feet elevation; not in New

Mexico. Arizona: mountains of southeastern and central parts,

from Cochise and Greenlee Counties west to Pima and Final Counties and northwest below Mogollón Rim to southern Coconino and

Yavapai Counties and Hualpai Mountains. This variety and other

varieties also in California and in Lower California, Mexico.

The typical form of this species, redberry buckthorn, found in

California and Lower California, is a low shrub less than 5 feet

tall, distinguished by the spine-tipped twigs and by smaller leaves

% to % inch long.

Though generally a shrub in Arizona, hoUyleaf buckthorn sometimes is a small tree with a distinct trunk. It is an evergreen component of the California chaparral vegetation which reappears in

the mountains of Arizona. As the spiny evergreen leaves and red

berries resemble holly, this attractive shrub could be used for

Christmas decorations. It is worthy of cultivation as an ornamental, though slow growing.

CALIFORNIA BUCKTHORN {Rhamnus californica Eschsch. var.

ursina (Greene) McMinn)

Also called coffeeberry, pigeonberry. Botanical synonyms: R,

ursina Greene, R. californica Eschsch. subsp. ursina (Greene)

Wolf.

Description: Evergreen shrub 6 feet or more in height, commonly branched from base but sometimes a small tree to 20 feet

tall and 6 inches in trunk diameter, with rounded spreading crown.

Leaves elliptical or oval, 11/4 to 3 inches long, short-pointed at apex

and base, edges finely and inconspicuously toothed and slightly

rolled under, leathery, above dull green and hairless or nearly so,

beneath paler and densely hairy. Flowers several in small cluster

at leaf axil, small, less than y^ inch long, greenish, from May to

July. Berries changing from green to red and to black at ma-
SOUTHWESTERN TREES 85

tt^^Âey

Lotewood

condalia.

Bitter condalia. Hollyleaf buckthorn. California

buckthorn.

turity, % inch in diameter, juicy, with 2 or 3 large seeds. Bark

smooth, gray.

Distribution: Common in canyons and along streams in mountains in chaparral, oak woodland, pinyon-juniper woodland, and

ponderosa pine forest zones, 3,500 to 7,000 feet elevation. New

Mexico : mountains of southwestern part from San Andres Mountains and Black Range westward. Arizona: mountains of southeastern and central parts, from Cochise and Graham Counties west

to Pima and Final Counties and northwest below Mogollón Rim to

southern Coconino and Yavapai Counties and Hualpai Mountains.

This variety also in southern Nevada and southeastern California,

and other varieties in southwestern Oregon, California, and Lrower

California, Mexico.

California buckthorn generally is a shrub, rather than a tree,

and has several varieties besides the southwestern one described

here. The typical form found along the Pacific Coast in California

and Oregon has the leaves hairless or nearly so beneath.

BIRCHLEAF BUCKTHORN (Rhamnus betulaefolia Greene)

Includes the variety R. betulaefolia var. obovata Kearney &

Peebles.

Description: Rounded shrub 8 feet or less in height, branching

from the base, or rarely a small tree to 18 feet tall and 4 inches or

more in trunk diameter. Lreaves deciduous, oblong to elliptical or in

a variety (var. obovata) obovate, 2 to 4 inches long, blunt- or shortpointed at apex, with edges finely and sharply toothed and not

rolled under, thin, bright green, slightly hairy beneath. Flowers

several in small cluster at leaf axil, small, less than Vs inch long,

greenish, in May and June. Berries % inch in diameter, juicy,

usually 3-seeded.

Distribution: Canyons and along streams in mountains, usually

in shade, oak woodland and ponderosa pine forest zones, 5,500 to

7,500 feet elevation. New Mexico: mountains of southern part,

north to White Mountains and west to Black Range and Mogollón

Mountains. Arizona: southeastern part from Cochise County to

southern Apache County ; the variety with obovate leaves in north-
86 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

ern part in Coconino County (Navajo Mountain, north rim of Grand

Canyon, and Kaibab Plateau). Also in southwestern Texas, and the

variety in southern Utah and Nevada.

This shrubby species has been found as a small tree in Jumpup

Canyon west of Kaibab Plateau by Leslie N. Goodding.

Sterculia Family (Sterculiaceae)

CALIFORNIA FREMONTIA (Fremontodendron californicum

(Torr.) Cov.)

Also called flannelbush, mountain leatherwood, California slippery-elm. Botanical synonym : Fremontia califomica Torr.

Description: Evergreen shrub or sometimes a small tree 10 to

20 feet tall. Twigs stout, densely rusty-hairy when young, becoming light reddish brown and hairless. Leaves on short lateral twigs,

broadly ovate or slightly heart-shaped, l^ to li^ inches long and

broad, usually 3-lobed with rounded lobes, thick, dull or dark green

and sparsely hairy above, beneath rusty and scurfy-hairy and with

prominent veins. Flowers numerous, single on short lateral twigs,

showy and large, 1^4 to 2 inches across, bright yellow, in April and

May. Seed capsule egg-shaped, 1 to li^ inches long, pointed at end,

4- or 5-celled, densely hairy. Bark deeply fissured and scaly, brownish gray, the inner bark mucilaginous. Wood hard, heavy, dark

brown tinged with red.

Distribution: Rare and local in a few places in mountain canyons in chaparral, 3,200 to 6,500 feet elevation; not in New

Mexico. Arizona: central part, mountains in northeastern Pinal

County, Mazatzal Mountains and near Payson in Gila County, and

Bradshaw Mountains (Yavapai County). Also widespread in

California.

California fremontia, a shrub of the California chaparral vegetation, is present also, though rather rare, in the same zone in

central Arizona, mainly associated with Arizona cypress. When in

flower the scattered plants are beautiful masses of yellow, standing

out on the mountainside from a distance. The odd, scurfy-hairy,

evergreen leaves, as well as the large bright yellow flowers, make

this species an attractive ornamental.

Fremontia was dedicated to Col. John C. Fremont (1813-90),

politician, soldier, and noted explorer of western United States.

This genus, which has another species in San Diego County, Calif.,

is the only native tree genus in the United States of the sterculia

family (Sterculiaceae). This tropical family with a few native

shrubby and herbaceous species contains the cacao tree, from which

chocolate is obtained, and the Chinese parasoltree, which is planted

and naturalized in the Southeast.

Tamarisk Family (Tamaricaceae)

FRENCH TAMARISK (Tamarix gallica L.)

Also called salt-cedar.

Description: Shrub or small tree 10 to 15 feet or more in height.
SOUTHWESTERN TREES 87

Birchleaf

buckthorn.

^^^Y

California

fremontia.

French tamarisk. Allthorn,

with slender upright or spreading branches and narrow or rounded

crown, resembling a juniper though not evergreen. Leaves deciduous, many, crowded, scalelike, about VIO inch long, narrow and

pointed, blue-green. Flowers numerous, crowded in many narrow

clusters 1 to 2 inches long at ends of twigs, small, Vie inch long,

pink, from March to August. Seed capsule 1/3 ii^ch long, reddish

brown, splitting into 3 to 5 parts, with many tiny hairy seeds.

Bark smoothish, becoming furrowed and ridged, reddish brown.

Distribution : Common or a'bundant along streams and irrigation

ditches, including alkali and salty soils, forming thickets, desert

and grassland zones, from slightly above sea level to 5,000 feet

elevation, not native. New Mexico: widely naturalized. Arizona:

extensively naturalized, even in Grand Canyon. Native of Mediterranean region but escaped and established abundantly in southern and western United States.

French tamarisk, commonly called "salt-cedar" though not related to the cedars or junipers, is sometimes confused with tamarack (Larix laricina (Du Roi) K. Koch), an unrelated, coniferous

tree of northeastern United States, Canada, and Alaska having a

similar name. Tamarisk is a good erosion-control plant but in places

is undesirable. Along Rio Grande and the Salt, Gila, and other

rivers, its abundance has created a problem of eradication. It

spreads by seeds and is easily propagated by cuttings or by transplanting small wild plants. It grows rapidly and is alkali-tolerant

and drought-resistant. The flowers are a source of honey.

Athel tamarisk (Tamarix aphylla (L.) Karst.; botanical

synonym, T. articulata Vahl), a related species from northeastern

Africa and western Asia, is a small to large, fast-growing, evergreen tree planted for shade and windbreaks in southern and central Arizona and to a lesser extent in southern New Mexico. It has

escaped from cultivation in a few places and may become naturalized eventually. The wiry, jointed, gray-green twigs are composed

of scale leaves Vie inch long, each encircling the twig and ending

in a minute point. The heavy, brittle, light-colored wood is a possible source of furniture and fence posts.
88 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Allthorn Family (Koeberliniaceae)

ALLTHORN {Koeberlinia spinosa Zuce.)

Also called crucifixion-thorn, crown-of-thorns, corona de Cristo,

junco. Variety: K. spinosa var. tenuispina Kearney & Peebles.

Description: Very spiny, much-branched, rounded spreading

shrub 3 to 6 feet tall or in a variety (var. tenuispina) also a small

tree to 15 feet in height, with numerous, stout, widely forking,

tangled, dark green branches and twigs, leafless most of the year.

Twigs stout, Ys inch or more in diameter, dark or pale green,

nearly hairless, ending in spines 1 to 2 inches long (2 to 4 inches

long and more slender in the variety). Leaves scalelike, soon shedding. Flowers few in small clusters on the twigs, less than ^4 inch

long, greenish white, from March to June. Fruit a shiny black

berry less than ^4 îîich in diameter. Bark dark green, becoming

scaly and gray. Wood very hard, heavy, dark brown streaked with

orange, with lighter sapwood.

Distribution: Clay or sandy plains, slopes and foothills, often

forming dense thickets and commonly growing with creosotebush

and tarbush ("blackbrush"), desert and desert grassland, 1,500 to

5,000 feet elevation. New Mexico : deserts of southern part, from

Tularosa Basin and Organ Mountains westward, north in Rio

Grande drainage to Sierra County and west to Gila River drainage.

Arizona: southeastern part, on Gila and San Pedro River drainages west to Winkelman and Tucson Mountains (Pima County) ;

the variety (var. tenuispina) in southwestern Arizona, in Eagle

Tail Mountains of western Maricopa County and mountains of

Yuma County and in Chocolate Mountains, southeastern California. The typical form also in southern and southwestern Texas and

in Mexico and Bolivia.

Allthorn is one of the three shrubby species of "crucifixionthorns'' in the Southwest. The variety (var. tenuispina) of southwestern Arizona, shown at left in drawing, becomes a small tree

and is distinguished by darker green twigs, longer spines 2 to 4

inches long, earlier flowering, and occurrence at lower elevations

and in more sandy soil. Allthorn is alone in its family.

Cactus Family (Cactaceae)

SAGUARO {Cereus giganteus Engelm.)

Also called giant cactus. Botanical synonym : Carnegiea gigantea

(Engelm.) Britton & Rose.

Description : Giant columnar tree cactus 20 to 35 feet or rarely

40 feet or more (maximum 52 feet) in height, with a single, continuous, massive, spiny yellow-green trunk 1 to 2 feet or more in

diameter, with usually 2 to 10 (or sometimes 20 or more) stout,

nearly erect or curved spiny branches. Trunk and branches cylindrical with rounded or flattened tips, yellow-green, with 12 to 30

prominent vertical fleshy ridges (or ribs) 2 to 4 inches apart and

with alternating grooves, the ridges bearing clusters of about 20
SOUTHWESTERN TREES 89

to 25 spreading gray spines V2 to 2 inches or more in length.

Leaves absent. Flowers many near tops of branches, large and

showy, funnel-shaped, 4 to 4^^ inches long and 2 to 3 inches across,

with many waxy white petals, with odor like melon, opening at

night, in May and June and sometimes again in August. Fruits

egg-shaped, 2 to 31/2 inches long, red, spineless or nearly so, fleshy,

sweet and edible, splitting open along usually 3 lines and resembling

flowers, maturing in June. Wood consisting of a framework or ring

of vertical rods or ribs separated by long rays and large pith,

visible as a skeleton after death and weathering of fleshy parts,

the ribs hard, lightweight, light brown.

Distribution: Perhaps the most characteristic tree species of

the Arizona desert, common on well-drained rocky or gravelly soils

of foothills and slopes and less frequently in valleys, 700 to 3,500

feet (rarely 4,500 feet) elevation ; toward the eastern and northern

parts of the range confined to south-facing slopes ; not in New Mexico. Arizona : southern, central, and southwestern parts, from eastern Pima and western Graham Counties northwest to southern

Yavapai and southern Mohave Counties and southwest to Yuma

County. At three localities west of Colorado River in southeastern

California. Also in Sonora, Mexico.

Saguaro (pronounced sah-WAH-ro), the State flower of Arizona,

has become a symbol for desert landscapes in general. One of the

finest stands of mature saguaros is preserved within Saguaro National Monument, conveniently located about 14 miles east of

Tucson. Other good cactus forests are protected in Papago State

Park and Phoenix South Mountain Park, both near Phoenix, at

Boyce Thompson Southwestern Arboretum near Superior, at Tucson Mountain Park, and at Organ Pipe Cactus National Monument

on the Mexican border.

The Pima and Papago Indians gather the red fruits and eat them

fresh, dried, or prepared as preserves, syrup, and beverages. They

make butter from the oily seeds. The woody framework of ribs is

useful in various ways, such as in making shelters, including roof

poles and sides of houses, for fences, for kindling fires, and for

novelties.

This is the largest cactus in the United States, though other

species of similar or greater size occur in Mexico and South America. The champion at Saguaro National Monument is 52 feet tall,

has 52 arms, an estimated weight of 10 tons, and an age of perhaps

235 years. Increase in height perhaps averages 3 inches or more a

year, varying from 2 to 8 inches or in the seedling stage only about

1 inch annually. Large individuals 30 to 40 feet tall are believed

to be as much as 150 to 200 years old and to weigh as much as

6 to 8 tons, most of which is water.

Saguaros are trees exceptionally well adapted to severe desert

conditions, though they thrive in areas with rainfall above average

for deserts, locally as much as 15 inches a year. Water from rains

is absorbed quickly by the shallow roots spreading as much as 50

feet in every direction and is stored in quantity in the thick succulent trunks and branches for growth over the long dry periods. The

relatively small surface area exposed, the thick, tough, waterproof
90 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

outer layer, and absence of leaves all tend to reduce water loss to

the hot dry desert air. Specialized ridged green stems without dead

bark substitute for leaves in manufacturing food, while the dense

spreading spines prevent destruction by desert animals.

These giant succulents grow in the warmer places, such as ridges

and southern or southwestern exposures, rather than in valleys,

where cold air drains from the heights above. Continuous temperatures below freezing for 36 hours or more, that is, one entire

day including two nights, will kill the plants or injure them

severely. Rocky hillsides, where saguaros generally grow, provide

better anchorage for the roots than do fine-textured soils of plains.

Though the weight of these heavy plants is well centered and balanced, uprooting of large plants by strong winds in wet weather,

when the ground is soft, probably is one of the main causes of

death.

Some saguaros have been killed by a bacterial rot disease, which

has become serious in a few localities. Rare individuals have a

broadly spreading growth, or crest, at the top. This fan-shaped or

cristate condition, though interesting as an oddity, represents abnormal growth resulting from an injury at the apex caused by

fungi, bacteria, birds, or insects. Round holes observed near tops of

branches are made by Gila woodpeckers and gilded flickers for

their nests and afterwards are occupied by elf owls.

ORGANPIPE CACTUS {Cereus thurberi Engelm.)

Also called pitahaya, pitahaya dulce. Botanical synonym : Lemaireocereits thurberi (Engelm.) Britton & Rose.

Description: Large treelike cactus 10 to 15 feet or up to 25 feet

in height, without a single trunk but with many (10 to 20 or more)

erect, columnar, spiny, green branches from the ground, unbranched above unless injured. Branches cylindrical, 5 to 8 inches

in diameter, with 12 to 19 prominent vertical fleshy ridges (or ribs)

less than II/2 inches apart and with alternating grooves, the ridges

bearing clusters of about 10 to 19 gray or black spreading spines

1/2 to 11/2 inches long. Leaves absent. Flowers scattered near tops

of branches, large, 21/2 to 3 inches long and IVo to 2 inches across,

with petals brownish green to greenish white or purple, opening at

night, from May to July. Fruits egg-shaped or nearly spherical, 2

to 3 inches in diameter, red, with many black spines which are shed

at maturity, juicy, sweet and edible, bursting irregularly.

Distribution : Of restricted occurrence on southwestern slopes of

mountains in desert, 1,000 to 3,500 feet elevation, in southern Arizona ; not in New Mexico. Arizona : desert mountains in southern

part near Mexican border, chiefly in Pima County, from Roskruge

Mountains and Picacho Mountains (southern Pinal County) west

to southern Maricopa County and to Growler Mountains and Organ

Pipe Cactus National Monument. Also in Sonora and Lower California, Mexico.

Organpipe cactus, with branches slightly suggesting a pipe

organ, is of tree size, though without a single trunk, and probably

should be included as a tree. This species is protected in the Organ
SOUTHWESTERN TREES 91

Saguaro. Organpipe cactus. Senita.

Pipe Cactus National Monument, an area of 5,127 square miles

located on the Mexican boundary south of Ajo in western Pima

County. The plants are sensitive to frost, which sometimes kills the

growing tips. Papago Indians harvest quantities of the sweet

fruits.

SENITA (Cereus schottii Engelm.)

Botanical synonym: Lophocereus schottii (Engelm.) Britton &

Rose.

Description: Large treelike cactus 5 to 20 feet tall, without a

single trunk, with many (up to 50 or more) erect, columnar, spiny,

yellow-green branches from or near the ground and unbranched

above. Branches angular, 4 to 8 inches in diameter, with usually

5 to 7 prominent vertical fleshy ridges (or ribs) 2 to 4 inches apart

and with alternating grooves, the ridges on lower 4 to 5 feet spineless or with clusters of about 15 or fewer spreading gray spines

about 1/2 inch in length, the ridges on upper part of branch bearing

clusters of about 30 gray, twisted, bristlelike spines 1 to 2 inches

long. Leaves absent. Flowers near tops of branches, 1^4 to II/2

inches long and 1 inch across, with pink petals, odorless, opening at

night, from April to August. Fruits nearly spherical, about 1 inch

in diameter, red, almost spineless, fleshy, bursting irregularly.

Distribution: Very rare and local on clay soils of valleys and

plains, desert zone, about 1,500 feet elevation, southern Arizona

on Mexican border ; not in New Mexico. Arizona : about 50 plants in

and near southeastern boundary of Organ Pipe Cactus National

Monument, western Pima County. Also in Sonora and Lower California, Mexico.

Senita perhaps may be included as a tree because of its many

columnar branches of tree size, though without a definite trunk.
92 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

The common name, meaning old, or an old person, refers to the

conspicuous long bristles, resembling gray hair or beard, in the

upper part of the branches. According to Benson (Ariz. Univ.

Biol. Sei. Bul. 5: 76.1940), the number of wild plants of this species

in the United States is less than 50. Fortunately, most of these

are preserved in Organ Pipe Cactus National Monument.

JUMPING CHOLLA (Opuntia fulgida Engelm.)

Also called Sonora jumping cholla. Variety: O. fulgida var.

mammillata (Schott) Coult.

Description: Jointed, very spiny, branching cactus, commonly

treelike shrub 6 feet or less in height or occasionally a small tree

to 15 feet tall. Trunk as much as 6 inches in diameter, usually with

several large spreading branches less than 3 feet above the ground

forming an irregular open much-branched crown. Joints of

branches cylindrical, 6 to 8 inches long, I14 to 2 inches in diameter,

pale green but appearing straw-colored because of the numerous

spines, fleshy in outer part and becoming woody within, readily

detached, bearing many tubercles, each with a cluster of 2 to 12

large brown spines % to ll^ inch long and covered with strawcolored sheaths for a year or more; the variety (var. mammillata)

with thicker branches, larger tubercles and 2 to 6 shorter spines

1/^ inch long. Leaves narrowly cylindrical, 1/2 to 1 inch long, light

green, fleshy, soon falling. Flowers about 1 inch across, with 5 to 8

petals, pink or white streaked with lavender, from May to August.

Fruits pear-shaped, 1 to 1% inches long and % inch in diameter,

green, tubercled but not spiny, fleshy, remaining attached many

years and bearing new flowers and fruits annually, the many

proliferating fruits hanging down in long branched chains or clusters. Bark of trunk and larger branches rough, scaly, spineless,

black. Wood a hollow, perforated, gray cylinder with thick pith

and broad rays, hard, lightweight.

Distribution : Often abundant and dominant and forming dense

"cactus forests," sandy soils of valleys, plains, and slopes, cactusshrub desert, 1,000 to 4,500 feet elevation; not in New Mexico.

Arizona : southern part, from Cochise and Graham Counties west

to Bill Williams River in southern Mohave County and to Yuma

County. Also in Sonora and Sinaloa, northern Mexico.

Various erect, mostly shrubby cacti with jointed branches are

known by the common name cholla (pronounced CHAW-ya or

CHO-ya). This name, meaning skull or head in Spanish, may have

been suggested by the short, thick branches of some species. Jumping cholla, the largest and perhaps most distinctive of the native

chollas, forms dense cactus forests in some areas, especially near

Tucson and Florence. Chollas of several species are rapidly spreading and have become a problem on some range lands in southern

Arizona.

This species is easily recognized by the black trunks, the large

hanging clusters of proliferating fruits, and the straw color of the

joints caused by the numerous spines and sheaths. The impenetrable armed joints are easily detached by touching and adhere to
SOUTHWESTERN TREES 93

Jumping cholla Tasajo. Staghorn cholla.

clothing and skin; hence the common name implying that they

jump out and attach themselves to passersby. The sharp barbed

spines penetrate the flesh, causing pain, and are not easily extracted. Detached branches of chollas will root and start new

plants. The dead, weathered wood of old branches, in the shape of

a hollow cylinder with numerous holes after decay of the softer

tissues, is used in making novelties.

TASAJO {Opuntia spinosior (Engelm.) Tourney)

Also called cane cholla.

Description : Jointed, branching cactus, shrubby or treelike and

usually less than 8 feet tall but sometimes a small tree 10 feet

tall and 6 inches in trunk diameter, with irregular open crown of

many spiny branches. Larger branches usually several at a point

and spreading at right angles, smaller branches often 2-forked.

Joints of branches cylindrical, 4 to 12 inches long, % to 1^4 inches

in diameter, fleshy in outer part and becoming woody within, bearing very many tubercles, each with a cluster of 10 to 20 usually

gray spines % to 1/2 inch long. Leaves narrowly cylindrical, %

inch long, fleshy, soon falling. Flowers few, clustered at ends of

branches, large, 1^4 to 2 inches across, with about 10 petals, varying in color from yellow to red, white, or purple, in May and June.

Fruits pear-shaped, 1 to li/^ inches long and broad, bright lemon

yellow at maturity, strongly tubercled and becoming spineless,

fleshy, remaining attached through the winter. Bark of trunk and

larger branches nearly black, ridged and scaly, spineless. Wood

a hollow, perforated, brown cylinder, hard, lightweight.

Distribution : Common and widely distributed, especially typical

of desert grassland in southern Arizona but ranging from desert

to oak woodland and pinyon-juniper woodland and occasionally to

ponderosa pine forest, 1,200 to 7,000 feet elevation. New Mexico:
94 HANDBOOK NO, 9, U. S. DEPARTMENT OF AGRICULTURE

southwestern corner, in Luna, Hidalgo, and Grant Counties. Arizona: southeastern quarter, northwest to Bradshaw Mountains

(Yavapai County) and southwest to Baboquivari Valley (Pima

County). Also in Sonora, Mexico.

Tasajo (meaning jerked beef in Spanish) is a shrubby cholla in

New Mexico but becomes treelike in Arizona. Canes and other

novelties are made from the hollow wood of old trunks and large

branches, which in this species are long and straight. The fruits

are eaten by cattle. Hybrids of this species with jumping cholla,

having intermediate characters, have been found along Gila River

near Florence, Final County, Ariz.

STAGHORN CHOLLA (Opuntia versicolor Engelm.)

Also called tree cholla, deerhorn cholla.

Description: Jointed, very spiny, branching cactus, treelike

shrub or sometimes a small tree up to 12 feet tall, with a trunk as

much as 6 inches in diameter and with broad, rounded crown of

many spreading branches. Joints of branches cylindrical, 4 to 12

inches or more in length, % to 1 inch in diameter, purplish green

or dark green, fleshy in outer part and becoming woody within,

bearing many long tubercles, each with a cluster of 5 to 10 or

more gray or purplish spines l^ to % inch long but of uneven

length. Leaves narrowly cylindrical, % inch long, fleshy, soon

falling. Flowers few together at ends of branches, large, about

IVâ inches across, with many petals, varying in color, commonly

orange or brown but also yellow, green, or red, in May. Fruits

single or sometimes 2 or 3 in a chain, pear-shaped, 1 to IV2 inches

or more in length and % to 1 inch in diameter, green tinged with

purple or red, tubercled, usually not spiny, fleshy, remaining attached through the winter. Bark of trunk light brown or purple,

smoothish, becoming scaly at base. Wood a hollow, perforated,

gray cylinder, hard, lightweight.

Distribution: Common in valleys and washes, and on watered

slopes of foothills and mesas, cactus-shrub desert, 1,200 to 4,000

feet elevation, southern Arizona; not in New Mexico. Arizona:

southern part, Pima and Final Counties, from Tanque Verde Mountains and Santa Cruz River valley west to Baboquivari Valley and

Comobabi Mountains. Also in northern Sonora, Mexico.

The common name refers to the resemblance of the widely

spreading forked branches to a deer's antlers.

BUCKHORN CHOLLA (Opuntia acanthocarpa Engelm. & Bigel.)

Variety: O. acanthocarpa var. thornberi (Thornber & Bonker)

L. Benson (botanical synonym, 0. thornberi Thornber & Bonker).

Description: Jointed, branching cactus, shrubby or treelike,

commonly a shrub 3 to 8 feet tall but rarely a small tree to 15

feet in height, with short trunk and open or dense crown of long

spiny branches. Joints of branches cylindrical, mostly 6 to 12

inches in length and 1 inch or more in diameter (% to 1 inch in

a variety, var. thornberi), gray-green, fleshy in outer part but be-
SOUTHWESTERN TREES 95

Buckhorn cholla. Red-osier dogwood. Arizona madrona. Texas madrone.

coming woody within, with long narrow tubercles each with a

cluster of 6 to 20 brown spines to 1 or IV2 inches long (shorter in

the variety) in straw-colored sheaths. Flowers large, IV2 to 2V2

inches across, usually red or yellow in April and May. Fruits pearshaped, about 1 inch long, dry and shriveled, spiny, not remaining

attached or bearing flowers.

Distribution: Common on sandy flats and washes in desert, 1,500

to 4,000 feet elevation; not in New Mexico. Arizona: southern

and western parts, from Graham County and northern Pima

County, northwest and west to Mohave and Yuma Counties. The

typical form also in southwestern Utah, southern Nevada, southeastern California, and Sonora, Mexico.

This species occasionally becomes treelike in Arizona, though

usually shrubby, and accordingly is included here. Robert H.

Peebles (Cact. and Succulent Jour. 9: 36. 1937) has recorded

exceptional individuals of the typical form 15 feet tall in hills

east of Hualpai Mountains (Mohave County) and has observed

treelike plants of the variety (var. thomberi) in the vicinity of

Coolidge Dam (Gila County). Another variety in southern Arizona

is a low shrub.

Dogwood Family (Cornaceae)

RED-OSIER DOGWOOD (Cornus stolonifera Michx.)

Botanical synonym : C, instolonea A. Neis.

Description: Usually a shrub 8 feet or less in height but reported as rarely a small tree in southern Arizona. Branches and

twigs purplish red, finely hairy. Leaves paired, ovate or elliptical,

2 to Sy2 inches long, short-pointed, edges not toothed, dark green

and nearly hairless above, beneath pale or whitish, and finely

hairy, with about 5 long and curved veins on each side of midrib.

Flowers several in flat-topped cluster 1 to 2 inches broad, small,

less than 14 inch across, white, in June and July. Fruit white,

14, inch in diameter, 1-seeded. Bark greenish brown, smooth.
96 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Distribution: Common along streams and canyons in mountains and plateaus, ponderosa pine forest and Douglas-fir forest,

6,000 to 9,000 feet elevation, widely distributed. New Mexico:

high njountains in western two-thirds, from Sacramento Mountains north to Sandia Mountains and Sangre de Cristo Range and

southwest to Mogollón Mountains. Arizona: northeastern half,

west to Grand Canyon and to Pima County. Widely distributed

from Newfoundland across Canada to Alaska, south in western

mountains to California, Arizona, New Mexico, and northern

Mexico, and south in northeast to Nebraska, Kentucky, and

Virginia.

Red-osier dogwood is reported to reach tree size on Santa Catalina Mountains in southern Arizona. Records of large individuals

and their measurements would be welcome. The common name

refers to the resemblance of the reddish branches and twigs to

those of some willows.

Heath Family (Ericaceae)

ARIZONA MADRONE (Arbutus arizonica (A. Gray) Sarg.)

Also called Arizona madroño.

Description: Evergreen medium-sized tree to 50 feet or more

in height and 2 feet or more in trunk diameter, with compact,

rounded crown. Twigs finely hairy, becoming reddish brown and

peeling off in scales. Leaves lance-shaped, IV2 to 3 inches long,

short-pointed, edges without teeth or inconspicuously saw-toothed,

thick and rigid, shiny light green above and paler beneath. Flowers

in hairy terminal clusters 2 to 2I/2 inches long, urn-shaped, 14 inch

long, white or pink, from April to September. Fruit berrylike,

% inch in diameter, orange red, finely warty, mealy and sweetish,

with large stones. Bark of branches thin, reddish brown, peeling

off in thin scales, on larger branches and trunks divided into

squarish plates and light gray or whitish. Wood heavy, light brown

tinged with red.

Distribution: Mountains in oak woodland, 4,000 to 8,000 feet

elevation, near Mexican border. New Mexico: mountains of extreme southwestern corner, in Hidalgo County. Arizona: mountains of southeastern part, in Cochise, Graham, and Pima (Santa

Catalina and Santa Rita Mountains) Counties. Also in northern

Mexico.

Arizona madrone should make an attractive ornamental tree,

though probably of slow growth. Under some conditions drops of

water exude from the leaves, as if the trees were weeping or were

**raintrees.'*

TEXAS MADRONE {Arbutus texana Buckl.)

Also called Texas madroño.

Description : Evergreen small tree to 20 feet tall and 1 foot in

trunk diameter. Twigs bright red, densely hairy when young, becoming dark red brown and scaly. Leaves oval or lance-shaped, 1
SOUTHWESTERN TREES 97

to 3 inches long, rounded or short-pointed at apex, edges usually

without teeth, thick and rigid, dark green and hairless above, paler

and slightly hairy beneath. Flowers in hairy terminal clusters

2V2 inches long, urn-shaped, 14 inch long, white or pink. Fruit

berrylike, % inch in diameter, dark red, finely warty, mealy and

sweetish, with large stone. Bark of branches thin, orange-red, separating into papery scales, on larger trunks divided into square

plates and dark reddish brown. Wood hard, heavy, brown tinged

with red.

Distribution: Local in mountains in oak woodland zone, about

6,000 feet elevation, Guadalupe Mountains of southeastern New

Mexico ; not in Arizona. New Mexico : known only from Guadalupe

Mountains in southwestern Eddy County, near Texas border. Also

in central and western Texas and northern Mexico.

Sapote Family (Sapotaceae)

GUM BUMELIA (Bumelia lanuginosa (Michx.) Pars. var. rigida

A. Gray)

Also called chittamwood, gum-elastic. Botanical synonym: B.

rigida (A. Gray) Small.

Description : Spiny shrub or small tree to 13 feet tall, with trunk

to 8 inches in diameter, and with compact crown of stiflf spreading

branches. Twigs stiff, brown, ending in stout spines and with additional spines single at base of leaves. Leaves single or clustered,

elliptical or reverse lance-shaped, % to 1% inches long, rounded at

apex and narrowed toward base, edges without teeth, leathery,

with matted white or tan hairs, especially beneath. Flowers several, in small clusters along the twigs, small, less than 14 iï^^h

across, whitish, fragrant, in June. Fruits egg-shaped, % inch or

less in length, purplish black, juicy, 1-seeded. Bark fissured and

scaly, dark gray.

Distribution : Along streams and washes, often forming thickets,

in upper part of desert, desert grassland, and oak woodland, 3,000

to 5,300 feet elevation, Mexican border region. New Mexico: extreme southwestern corner, in southern Hidalgo County. Arizona :

southeastern part, scattered in Cochise and Pima Counties west to

Santa Catalina and Baboquivari Mountains. This variety is found

also in Texas and northern Mexico. The species including varieties

ranges from Florida west to Louisiana, Missouri, and southeastern

Arizona, and south to northern Mexico.

The typical form of gum bumelia, occurring in the southeastern

States, differs from the southwestern variety described here in

being a medium-sized tree with larger and broader leaves mostly

2 to 4 inches long and with fewer spines. The common name refers

to the gum which exudes from cuts in the trunk and which is

chewed by children. Gum bumelia is the only southwestern representative of the sapote family (Sapotaceae), which is chiefly

tropical. Sapodilla, the principal tree from which chewing gum is

obtained, is a member of this family.
98 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

Olive Family (Oleaceae)

SINGLELEAF ASH {Fraxinus anómala Torr.)

Description: Shrub or sometimes a small tree to 20 feet tall

and 6 inches in trunk diameter, with rounded crown. Twigs 4-

angled, brown, without hairs. Leaves paired, simple or occasionally

of 2 or 3 leaflets. Leaves broadly ovate or nearly round, I14 to 2

inches long (or leaflets 1 to ly^ inches long), rounded or shortpointed at apex, inconspicuously wavy-toothed or without teeth,

leathery, dark green above, paler beneath, becoming hairless.

Flowers appearing with the leaves, in small hairy clusters, small,

in April. Fruits few in clusters, long-winged **keys" 1/2 inch long,

with broad rounded wing % inch wide extending to base. Bark

ñssured into narrow ridges, dark brown, reddish tinged. Wood

hard, heavy, light brown.

Distribution: Canyons and hillsides, often on very dry rocky

slopes, in upper desert, pinyon-juniper woodland, and lower ponderosa pine forest zones, 2,000 to 6,000 feet elevation. New Mexico: extreme northwestern corner in Carrizo Mountains, northwestern San Juan County. Arizona : northern part, from northern

Apache County to Coconino County, where it is common at Grand

Canyon. Also in southwestern Colorado, southern Utah, southern

Nevada, and southeastern California.

Singleleaf ash generally has simple leaves, making this species

almost unique among the other ashes, which have pinnately compound leaves. A variety of fragrant ash in Arizona occasionally

has simple leaves also.

LOWELL ASH (Fraxinus lowellU Sarg.)

Description: Shrub or small tree to 25 feet in height. Twigs 4-

angled, often winged, orange-brown the first year, becoming graybrown. Leaves paired, pinnately compound, 31/2 to 6 inches long.

Leaflets 3, 5, or 7, ovate, 2l^ to 3 inches long, long- or short-pointed,

edges saw-toothed, slightly leathery, yellow-green, without hairs

or slightly hairy. Flowers male and female separate, in clusters

14 to 1% inches long, small, in March. Fruits several in clusters,

long-winged "keys" 1 to l^/^ inch long with broad rounded wing

% inch or less in width and extending to base. Bark deeply furrowed, brown.

Distribution: Along streams and canyons, 3,200 to 6,500 feet

elevation, oak woodland and upper desert zones, known only from

central Arizona ; not in New Mexico. Arizona : central part, from

western Gila and eastern Maricopa Counties northwest to Coconino

County (Oak Creek Canyon and Havasu Canyon), Yavapai County,

and eastern Mohave County.

Lowell ash commemorates Percival Lowell (1855-1916), American astronomer who established Lowell Observatory at Flagstaff

and who found this ash in Oak Creek Canyon while collecting tree

specimens in northern Arizona.
SOUTHWESTERN TREES 99

Gum bumelia. Singleleaf ash.

FRAGRANT ASH (Fraxinus cuspidata Torr.)

Also called flowering ash. Variety: F. cuspidata var. Tnacropetala (Eastw.) Rehd.

Description : Shrub or small tree to 20 feet tall and 8 inches in

trunk diameter. Leaves paired, pinnately compound, 3 to 7 inches

long-, or occasionally simple (in var. "^nacropetala). Leaflets 3 to 7,

long-stalked, lance-shaped or ovate, IV^ to 2V2 inches long, longpointed, slightly saw-toothed or without teeth, thin, shiny dark

green above, beneath paler and slightly hairy when young.

Flowers appearing with the leaves, in hairless clusters 3 to 4 inches

long, about i/^ inch long, white, fragrant, differing from other

native ashes in the larger size and presence of a 4-parted whitish

corolla, in May and June. Fruits several in clusters, long-winged

oblong "keys" % to 1 inch long with rounded wing l^ inch wide

in upper half and extending nearly to base of flattened body. Bark

smoothish, gray, becoming much fissured into ridges and scaly.

Distribution : Scattered and local on rocky slopes of canyons and

mountains in oak woodland zone, 4,500 to 7,000 feet elevation. New

Mexico: mountains of southern and northwestern parts, from

Sacramento Mountains west to Hidalgo County and in Valencia and

McKinley Counties. Arizona: northern part in Coconino County

(Grand Canyon, Sycamore Canyon, etc.) and Yavapai County

(Verde River valley). Also in southwestern Texas.

The Arizona plants are of a variety (var. macropetala), differing

in the usually fewer, broader leaflets without toothed edges or

occasionally simple leaves. Fragrant ash deserves to be planted

more as an ornamental, because of the showy pleasant-scented flowers and attractive foliage.

GREGG ASH (Fraxinus greggti A. Gray)

Also called littleleaf ash.

Description: Shrub or sometimes a small tree to 20 feet tall

and 8 inches in trunk diameter, nearly evergreen. Leaves paired,

pinnately compound, 1 to II/2 inches long, axis narrowly winged,

remaining attached through the winter until after flowering time.

Leaflets usually 5 or 7 (or 3), reverse lance-shaped or obovate,
100 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

1/2 to % (to 11/2) inches long, rounded at apex, inconspicuously

toothed or without teeth, thick and leathery, dark green above,

beneath paler and covered with small black dots. Flowers partly

male and female and partly bisexual, appearing before the leaves,

in small clusters, small. Fruits few in cluster, long-winged "keys"

V2 to % inch long with broad wing about ^4 inch wide extending to

base and much longer than body. Bark smooth, thin, gray. Wood

hard, heavy, brown.

Distribution : At a single Arizona locality, on rocky slopes and

in canyons, desert and oak woodland, 3,600 to 5,000 feet elevation,

on Mexican border ; not in New Mexico. Arizona : known only from

Sycamore Canyon near Ruby (Santa Cruz County). Also in southwestern Texas and Mexico.

This ash bears the name of its discoverer, Josiah Gregg (1806-

50), an early American trader in the West and author of The

Commerce of the Prairies. He collected plant specimens in northern

Mexico.

VELVET ASH (Fraxinus velutina Torr.)

Also called desert ash, smooth ash, Arizona ash, Toumey ash,

fresno. Botanical synonyms: F. velutina var. glabra Rehd., F,

velutina wai\ toumeyi (Britton) Rehd., F, standleyi Rehd,

Description: Small to medium-sized tree to 40 feet tall and 1

foot or more in trunk diameter, with spreading branches and

rounded crown. Twigs brown, hairy or without hairs. Leaves

paired, pinnately compound, 3 to 6 inches long. Leaflets 5 to 9,

varying greatly in appearance, lance-shaped or elliptical, 1 to 3

inches long, short- or long-pointed, edges slightly toothed or without teeth, varying from thin to thick and leathery, varying from

densely short-hairy beneath to hairless. Flowers yellow (male)

and green (female) on different trees (dioecious), appearing before

the leaves, many in clusters, small, in March and April. Fruits

many in dense clusters, long-winged "keys" % to 1 inch long,

wing not extending to base. Bark deeply furrowed into broad

ridges, gray. Wood soft, heavy, light brown.

Distribution : Common and characteristic tree of stream banks,

moist washes, and moist canyons, chiefly in mountains, in the

desert, desert grassland, oak woodland, and ponderosa pine forest

zones, 2,500 to 7,000 feet elevation. New Mexico: mountains in

southern part, from White Mountains west to Black Range and

Mogollón Mountains and south to southern border. Arizona: southeastern, central, and northwestern parts, from Cochise and southern Apache Counties west to Santa Cruz and Pima (Baboquivari

Mountains) Counties and northwest below Mogollón Rim to southern

Coconino (Oak Creek Canyon) and Yavapai Counties; also in lower

Grand Canyon region in Mohave County. Southern and southwestern Texas to southwestern Utah, southern Nevada, and southern California. Also in northern Mexico.

Velvet ash is highly variable in characters of leaflets, such as

shape, edges, thickness, hairiness, and length of leaflet stalks.
SOUTHWESTERN TREES 101

Gregg ash. Velvet ash. Desert-olive forestiera, Tree tobacco.

Some botanists distinguish two or three varieties. In one common

form the foliage and twigs are without hairs. This species is

popular as a good shade tree and is widely planted in southern

Arizona and California.

DESERT-OLIVE FORESTIERA {Forestiera phillyreoides

(Benth.) Torr.)

Also called wild-olive, desert-olive.

Description: Much-branched shrub 3 to 12 feet tall or sometimes

a small tree as much as 20 to 25 feet tall and 8 inches in trunk

diameter, evergreen or nearly so. Leaves paired, more or less evergreen, lance-shaped or reverse lance-shaped, % to 1 inch long,

short-pointed, edges not toothed but slightly rolled under, green

and hairy on both sides. Flowers male and female on different

plants (dioecious), in small lateral clusters, very small, from December to March. Fruit egg-shaped, 14 to % inch long, one-sided,

resemblmg a small olive, with thin flesh, 1-seeded. Wood very hard.

Distribution: Local on dry rocky slopes and canyons in desert,

often forming thickets, 2,500 to 4,500 feet elevation; not in New

Mexico. Arizona: of limited range and local on mountains of southwestern part, from Tucson Mountains and Baboquivari Mountains

(Pima County) and Sierra Estrella (Maricopa County) west to

Kofa Mountains (Yuma County). Also in Mexico.

This species, known from a few desert localities in southwestern

Arizona as a shrub, sometimes becomes a small tree, according to

Leslie N. Goodding, and therefore is to be added to the list of

native trees in the United States.

Nightshade Family (Solanaceae)

TREE TOBACCO {Nicotiana glauca Graham)

Description: Evergreen shrub or small tree 6 to 20 feet tall,

with a trunk as much as 3 to 6 inches in diameter. Leaves longstalked, ovate, 2 to 6 inches long, blunt- or short-pointed, edges
102 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

without teeth, blue-green and covered with a bloom. Flowers in

branched clusters at ends of twigs, tubular and narrow, about IV2

inches long, yellow, nearly throughout the year. Seed capsules

egg-shaped, % to i/^ inch long, containing many tiny seeds. Bark

smooth, blue-green.

Distribution: Common and widespread along stream beds,

ditches, and washes in desert, from slightly above sea level to

3,000 feet elevation or sometimes'higher ; not native. New Mexico :

introduced in southern part. Arizona: deserts of southern and

central parts, widely naturalized. Also established in Florida and

from southern Texas to California. Native of Argentina and Chile

but extensively naturalized in the tropics.

Tree tobacco is unusual as an introduced shrub or tree sufficiently

hardy to become adapted to moist soils in southwestern deserts. It

is planted also as an ornamental and has escaped from cultivation

so that, especially along streams, it is a conspicuous feature of local

Arizona landscapes.

Bignonia Family (Bîgnonîaceae)

DESERTWILLOW {Chilopsis linearis (Cav.) Sweet)

Includes: C. linearis var. arcvxita Fosberg, C linearis var.

glutinosa (Engelm.) Fosberg.

Description: Large shrub or small tree to 25 feet or more in

height, with spreading crown. Twigs slender, varying in varieties

from woolly to sticky or neither. Leaves very narrow or narrowly

lance-shaped, 3 to 6 inches long and less than % inch wide, straight

or curved, not toothed, light green. Flowers several in clusters,

large and showy, tubular, 1 to I14 inches long, whitish and tinged

with purple or pink, fragrant, from April to August. Seed capsules

long and very narrow, 4 to 8 inches long and less than % inch in

diameter, remaining attached in winter, containing many flat seeds

with 2 hairy wings. Bark ridged and scaly, dark brown. Wood

soft, brown streaked with yellow.

Distribution: Along washes and drainages in plains, mesas,

and foothills, desert and desert grassland, 1,500 to 5,000 (or 6,000)

feet elevation. New Mexico: deserts of southern part, north in

Fecos River valley to Roswell and in Rio Grande drainage to Albuquerque, and west to Gila River drainage. Arizona: southern,

central, and northwestern parts, from Cochise and Greenlee Counties west to Santa Cruz and western Pima Counties and northwest

below Mogollón Rim to southern Coconino, Yavapai, and northern

Yuma Counties, and to lower Grand Canyon and northwestern corner of State in Mohave County. Southern and southwestern Texas

to southwestern Utah, southern Nevada, and southern California,

south to northern Mexico.

In spite of its general aspect and habitat in moist soil, desertwillow is not a true willow. Instead, it belongs to the same family

as catalpa (bigonia family, Bignoniaceae) and has similar large

flowers and long narrow fruits. As it forms thickets along washes,

desertwillow is important in erosion control and has been widely
SOUTHWESTERN TREES 103

1^ À

Desertwillow. Mexican elder. Blueberry elder.

planted for this purpose. It is propagated from seeds or cuttings,

grows rapidly, and sprouts after cut. Desertwillow is sometimes

used as an ornamental. The wood is durable and is suitable for

fence posts.

Honeysuckle Family (Caprifoliaeeae)

MEXICAN ELDER (Sambucus mexicana Presl)

Also called Arizona blueberry elder, Arizona elder, desert elderberry, sauco. Botanical synonyms : S. gUmea Nutt. var. arizonica

Sarg., S, cerúlea Raf, var. arizonica Sarg,, S. cerúlea var. mexicana (Presl) L. Benson.

Description : Evergreen small to medium-sized tree 20 to 30 feet

or more in height and 1 to 2 feet in trunk diameter, with compact,

rounded crown, and with branches and twigs having large pith.

Leaves paired, pinnately compound. Leaflets usually 3 (or 5),

elliptical or ovate, 1 to 3 inches long, short-pointed, finely sawtoothed, thick and leathery, hairy or without hairs. Flower cluster

flat-topped, 2 to 8 inches in diameter, containing many small, yellowish white flowers about Í4 inch across, nearly throughout the

year. Berries almost y^ inch in diameter, dark blue with a bloom,

edible. Bark scaly, light brown. Wood soft, lightweight, light

brown.

Distribution: Frequent along streams and drainages in desert

and desert grassland, 1,200 to 5,000 feet elevation. New Mexico:

southern part, along lower Rio Grande and Gila River drainages.

Arizona : southern and central parts, from Cochise County west to

Santa Cruz and Pima Counties and northwest to Gila, Yavapai, and

Mohave Counties. From southwestern Texas west to southern

California and in Mexico.

Mexican elder, one of the largest native elders, is distinguished

from other southwestern species by its larger size, evergreen leaves,

and occurrence in the desert, rather than mountains. These evergreen trees with numerous showy flower clusters are often cultivated as ornamentals and shade trees. The fruits are used in pies

and jellies and are eaten by birds.
104 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

BLUEBERRY ELDER {Sambucus glauca Nutt.)

Botanical synonyms: S. cerúlea Raf.; S. neomexicana (Woot.)

A. Neis. Variety: Velvet elder (S. glauca var. velutina (Durand

& Hilgard) Johnst. ; also called velvetleaf elder ; botanical synonym,

S. velutina Durand & Hilgard).

Description: Tall shrub or small tree to 20 feet in height, with

one or usually several trunks from base to 8 inches in diameter and

with compact rounded crown. Branches and twigs with large pith,

twigs without hairs or finely hairy. Leaves paired, pinnately compound, 5 to 7 inches long. Leaflets 5 to 9, ovate or lance-shaped, 1

to 5 inches long, long- or short-pointed, saw-toothed, thin or thick,

without hairs or hairy. Flower cluster flat-topped, 4 to 10 inches

across, containing many small, yellowish white flowers less than

14 inch across, from June to August. Berries % inch in diameter,

dark blue with a bloom, juicy and edible. Bark furrowed, gray.

Wood soft, lightweight, light brown.

Distribution : Streams, canyons, and other moist places in mountains, in ponderosa pine and Douglas-fir forest, 6,500 to 9,500 feet

elevation. New Mexico: high mountains of southern part, from

Sacramento and White Mountains west to Black Range, San Mateo

Mountains, and Mogollón Mountains. Arizona : high mountains and

plateaus except in northeastern and southwestern parts, from

Cochise County west to Pima County and northwest to Yavapai

County, Grand Canyon, and Hualpai Mountains. This species with

varieties is widely distributed from southwestern Texas and New

Mexico north to Montana, Alberta, and British Columbia, and

south to California and Arizona. Velvet elder (var. velutina), with

twigs and under surface of leaflets densely and finely hairy, is the

variety on Hualpai Mountains and is found also in California.

SELECTED REFERENCES

BAILEY, VERNON.

1913. LIFE ZONES AND CROP ZONES OF NEW MEXICO. U. S. Dept. Agr. Blol.

Surv., No. Amer. Fauna 35, 100 pp., illus.

BARNETT, HORACE L., and BARNETT, ALICE.

1939. NEW MEXICO TREES. 41 pp. N. Mex. State Col. [Processed.]

BENSON, LYMAN, and DARROW, ROBERT A.

1945. A MANUAL OF SOUTHWESTERN DESERT TREES AND SHRUBS. Ariz. Univ.

Blol. Sei. Bul. 6, 411 pp., illus.

THORNBER, J. J., NICHOL, A. A., and HAMILTON, LUCRETIA BREAZEALE.

1940. THE CACTI OF ARIZONA. Ariz. Univ. Biol. Sei. Bul. 5, 134 pp., illus.

CHAPEL, WILLIAM L.

1938, A GUIDE TO THE FOREST TREES OF ARIZONA AND NEW MEXICO. 52 pp.,

illus. U. S. Forest Serv. Southwestern Region. [Processed.]

DAYTON, WILLL4M A.

1931. IMPORTANT WESTERN BROWSE PLANTS. U. S. Dept. Agr. MisC. Pub.

101, 213 pp., illus.

DODGE, NATT N.

1936. TREES OF GRAND CANYON NATIONAL PARK. Grand Canyon Nat. Hist.

Assoc. Nat. Hist. Bui. 3, 69 pp., illus. [Processed.]

ENZIE, J. V.

1941. ORNAMENTAL TREES AND SHRUBS FOR NEW MEXICO. N. MeX. Agr. Expt.

Sta. Bui. 284, 48 pp., illus.

GooDDiNG, LESLIE N.

1938. NOTES ON NATIVE AND EXOTIC PLANTS IN REGION 8, WITH SPECIAL

REFERENCE TO THEIR VALUE IN THE SOIL CONSERVATION PROGRAM.

U. S. Dept. Agr. Soil Conserv. Serv. Region 8. 152 pp., illus.

Albuquerque, N. M. [Processed.]
SOUTHWESTERN TREES 105

1940. WILLOWS IN REGION VIII: NOTES ON THEIR CLASSIFICATION, DISTRIBUTION, AND PRESENT SIGNIFICANCE, WITH SUGGESTIONS FOR THEIR USE

IN EROSION CONTROL. U. S. Dept. Agr. Soil Conserv. Serv. Region

8, Region. Bui. 65, 12 pp., illus. [Processed.]

HARLOW, WILLIAM M., and HARRAR, ELLWOOD S.

1950. TEXTBOOK OF DENDROLOGY. Ed. 3, 655 pp., illus. New York.

HUNTER, BYRON, COCKERILL, P. W., and PINGREY, H. B.

1939. TYPE OF FARMING AND RANCHING AREAS IN NEW MEXICO, PART L N.

Mex. Agr. Expt. Sta. Bui. 261, 68 pp., illus.

KEARNEY, THOMAS H., and PEEBLES, ROBERT H.

1942. FLOWERING PLANTS AND FERNS OP ARIZONA. U. S. Dept. Agr. Misc.

Pub. 423, 1069 pp., illus.

LONGYEAR, BURTON 0.

1927. TREES AND SHRUBS OP THE ROCKY MOUNTAIN REGION, 244 pp., illus.

New York.

MEDLER, JOHN T., and HERSHEY, ARTHUR L.

[1937]. TREES OF NEW MEXICO. N. Mex. State Col. Biol. Sec. Nature Notes

V. 3, No. 1, illus. [Processed.]

NICHOL, A. A.

1937. THE NATURAL VEGETATION OF ARIZONA. Ariz. Univ. Agr. Expt. Sta.

Tech. Bui. 68: 181-222, illus.

PEARSON, G. A.

1931. FOREST TYPES IN THE SOUTHWEST AS DETERMINED BY CLIMATE AND SOIL.

U. S. Dept. Agr. Tech. Bui. 247, 144 pp., illus.

PRESTON, RICHARD J., JR.

1947. ROCKY MOUNTAIN TREES. Ed. 2, 285 pp., illus. Ames, Iowa.

SARGENT, CHARLES SPRAGUE.

1926. MANUAL OF THE TREES OP NORTH AMERICA. Ed. 2, reprinted with corrections. 910 pp., illus. Boston.

STANDLEY, PAUL C.

1920-26. TREES AND SHRUBS OF MEXICO. U. S. Nati. Mus., Contrib. U. S.

Nati. Herbarium v. 23, 1721 pp.

SUDWORTH, GEORGE B.

1915. THE CYPRESS AND JUNIPER TREES OF THE ROCKY MOUNTAIN REGION.

U. S. Dept. Agr. Bui. 207, 36 pp., illus.

1916. THE SPRUCE AND BALSAM FIR TREES OF THE ROCKY MOUNTAIN REGION.

U. S. Dept. Agr. Bui. 327, 43 pp., illus.

1917. THE PINE TREES OF THE ROCKY MOUNTAIN REGION. U. S. Dept. Agr.

Bul. 460, 47 pp., illus.

1918. MISCELLANEOUS CONIFERS OF THE ROCKY MOUNTAIN REGION. U. S.

Dept. Agr. Bui. 680, 45 pp., illus.

1927. CHECK LIST OF THE FOREST TREES OF THE UNITED STATES, THEIR NAMES

AND RANGES. U. S. Dept. Agr. Misc. Cir. 92, 295 pp.

1934. POPLARS, PRINCIPAL TREE WILLOWS AND WALNUTS OF THE ROCKY

MOUNTAIN REGION. U. S. Dept. Agr. Tech. Bui. 420, 112 pp., illus.

TiDESTROM, IVAR.

1925. FLORA OF UTAH AND NEVADA. U. S. Nati. Mus., Contrib. U. S. Nati.

Herbarium v. 25, 665 pp., illus.

and KiTTELL, SISTER TERESITA.

1941. A FLORA OF ARIZONA AND NEW MEXICO. 897 pp., illus. Washington,

D. C. [Processed.]

WOOTON, E. 0.

1913. TREES AND SHRUBS OF NEW MEXICO. N. Mex. Agr. Expt. Sta. Bui. 87,

159 pp., illus.

and STANDLEY, PAUL C.

1915. FLORA OP NEW MEXICO. U. S. Nati. Mus., Contrib. U. S. Nati, Herbarium V. 19, 794 pp.
INDEX OF COMMON AND SCIENTIFIC NAMES

Accepted plant names, both common and scientific, appear in

heavy type. Others are shown in ordinary type. Page numbers of

illustrations are in italics. This index also shows whether any

parts of common names are capitalized.

Abies arizonica, 20; concolor, id; lasiocarpa, 20; lasiocarpa var, arizonica,

20.

acacia, catclaw, 6S, 63; mescal, 65;

sweet, 6S, 64.

Acacia constricta, 65; farnesiana, 64;

greggii, 63.

Acer brachypterum, 81; glabrum, 80;

glabrum var. neomexicanum, 80;

grandidentatum, 81; grandidentatum var. brachypterum, 81; negundo

var. arizonicum, 80; negundo var.

interius, 80; neomexicanum, 80.

Aceraceae, 80.

ailanthus, 75; tree-of-heaven, 75.

ailanthus family, 74.

Ailanthus altissima, 75.

alamo, 33, 34.

alder, Arizona, 45, J^S; mountain, 45;

New Mexican, 45; thinleaf, 45, -45.

allthorn, 87, 88.

allthorn family, 88.

Alnus oblongifolia, 45; tenuifolia, 45.

Amelanchier australis, 56; bakeri, 56;

crenata, 56; goldmanii, 56; mormonica, 56; oreophila, 56; rubescens,

56; utahensis, 56.

Anacardiaceae, 78.

Arbutus arizonica, 96; texana, 96.

ash, Arizona, 100; desert, 100; flowering, 99; fragrant, 99, 99; Gregg, 99,

101; littleleaf, 99; Lowell, 98, 99;

singleleaf, 98, 99; smooth, 100;

Toumey, 100; velvet, 100, 101.

asp, quaking, 32.

aspen, 32; golden, 32; quaking, 32, SS.

balsam, white, 19, 20.

bayonet, Spanish, 28, 30.

beech family, 46.

bellota, 52.

Betula fontinalis, 44; occidentalis, 44.

Betulaceae, 44.

bignonia family, 102.

Bignoniaceae, 102.

birch, black, 44; red, 44; water, 44, 45.

birch family, 44.

bittersweet family, 79.

boxelder, 80; inland, 80, 81; Rocky

Mountain, 80.

Broussonetia secundiflora, 70.

buckthorn, birchleaf, 85, 87; California,

84, 85; hollyleaf, 84, 85; hollyleaf

redberry, 84.

buckthorn family, 83.

bumelia, gum, 97, 99,

Bumelia lanuginosa var. rigida, 97;

rigida, 97.

bursera, elephant, 76; fragrant, 75, 77.

bursera family, 75.

Bursera microphylla, 76; odorata, 75.

Burseraceae, 75.

Cactaceae, 88.

cactus, giant, 88; organpipe, 90, 91.

cactus family, 88.

California-palm, 24.

canotia, 79, 79.

Canotia holacantha, 79.

Caprifoliaceae, 103.

Carnegiea gigantea, 88.

cashew family, 78.

castor-bean, 76, 77.

catclaw, 63.

Celastraceae, 79.

Celtis laevigata var. reticulata, 53;

reticulata, 53.

Cerasus crenulata, 60.

Cercidium floridum, 69; microphyllum,

68; torreyanum, 69.

Cercis arizonica, 67; occidentalis, 67;

occidentalis var, orbiculata, 67.

Cercocarpus betuloides, 60; breviflorus, 59; ledifolius, 58; ledifolius

var. intercedens, 58; montanus var.

glaber, 60; montanus var. paucidentatus, 59; paucidentatus, 59.

Cereus giganteus, 88; schottii, 91;

thurberi, 90.

cherioni, 82.

cherry, bitter, 60, 61; Chisos wild, 62;

wild, 60, 61.

chilicote, 73.

Chilopsis linearis, 102; linearis var.

arcuata, 102; linearis var. glutinosa,

102.

china-tree, wild, 82.

chittamwood, 97.

chokecherry, black, 61; black western,

61; common, 61, 61; Gila, 62; southwestern, 61, 62; western, 61.

cholla, buckthorn, 94, 95; cane, 93;

deerhom, 94; jumping, 92, 93; Sonora jumping, 92; staghorn, 93, 94;

tree, 94.

cliffrose, 58, 59.

coffeeberry, 84.

106
SOUTHWESTERN TREES 107

condalia» bitter, 83, 85; lotewood, 83,

85.

Condalia globosa, 83; globosa var.

pubescens, 83; lycioides, 83; lycioides

var. canescens, 83; obtusifolia, 83.

copal, 76.

coralbean, 70; southwestern, 73, 75;

western, 73.

Cornaceae, 95.

Cornus instolonea, 95; stolonifera, 95.

corona de Cristo, 74, 88.

cottonwood, black, 31; Fremont, 33,

SS; lanceleaf, 32; mountain, 31; narrowleaf, 31, S3; plains, 34, S5; Rio

Grande, 3S, 34; valley, 34; Wislizenus, 34.

Cowania mexicana var. stansburiana,

58; stansburiana, 58.

Crataegus cerronis, 57; chrysocarpa,

56; erythropoda, 57; rivularis, 57;

rotundifolia, 56; wootoniana, 58.

crown-of-thoms, 88,

crucillo, white, 83.

crucifixion-thorn, 74, 79, 88.

Cupressus arizonica, 20; arizonica var.

bonita, 20 j glabra, 20.

cypress, Arizona, 20, 21; rough-bark

Arizona, 20; smooth, 20; smooth

Arizona, 20.

dagger, Spanish, 28, 29, 30.

dalea, smokethom, 71.

Dalea spinosa, 71.

desert-olive, 101.

desert-palm, 24.

desertwillow, 102, 103.

devilsclaw, 63.

dogwood, red-osier, 95, 95.

dogwood family, 95.

Douglas-fir, 18, 19; blue, 18; common,

18.

Douglas-spruce, 18.

elder, Arizona, 103; Arizona blueberry,

103; blueberry, 103, 104; Mexican,

103,103; velvet, 104; velvetleaf, 104.

elderberry, desert, 103.

elephanttree, 76, 77.

elm family, 53.

Ericaceae, 96.

Erythrina flabelliformis, 73.

Euphorbiaceae, 76.

Eysenhardtia orthocarpa, 70; polystachya, 70.

Fagaceae, 46.

fan-palm, California, 24.

fir, alpine, 20, 21; Arizona, 20; balsam,

19; corkbark, 20; red, 18; silver, 19;

white, 19, 19, 20; yellow, 18.

flannelbush, 86.

Forestiera, desert-olive, 101, 101.

Forestiera phillyreoides, 101.

Fraxinus anómala, 98; cuspidata, 99;

cuspidata var. macropetala, 99;

greggii, 99; lowellii, 98; standleyi,

100; velutina, 100; velutina var.

glabra, 100; velutina var. toumeyi,

100.

fremontia, California, 86, 87.

Fremontia califomica, 86.

Fremontodendron californicum, 86.

fresno, 100.

frijolito, 70.

goat-bean, 70.

gum-elastic, 97.

gray-thorn, 83.

hackberry, netleaf, 53, 55; western, 53.

haw, black, 57.

hawthorn, cerro, 57, 57; fireberry, 56,

57; river, 57, 57.

heath family, 96.

holacantha, 74, 75.

Holacantha emoryi, 74.

honeysuckle family, 103.

hophornbeam, Bailey, 44; Knowlton,

44, -45; western, 44.

hoptree, narrowleaf, 74, 75; pale, 73,

75.

horsebean, 67; littleleaf, 68.

huisache, 64.

Indian-bean, 73.

indigobush, 71.

ironwood, desert, 72.

jaboncillo, 82.

Jerusalem-thorn, 67, 69.

Joshua-tree, 27, 27.

Judas-tree, 67.

Juglaildaceae, 42.

Juglans major, 43; microcarpa, 42;

rupestris, 42; rupestris var. major,

43.

jumping-bean, Mexican, 77.

junco, 88.

Juniper, alligator, 21, 22; common, 24;

one-seed, 23, 25; Rocky Mountain,

21, 22; Utah, 24, 25; western, 22, 24.

Juniperus communis, 24; deppeana, 22;

deppeana var. pachyphloea, 22; gymnocarpa, 23; megalocarpa, 24; monosperma, 23; osteosperma, 24; pachyphloea, 22; scopulorum, 22; sibirica,

24; utahensis, 24.

kidneywood, 70, 71.

Koeberlinia spinosa, 88; spinosa var.

tenuispina, 88.

Koeberliniaceae, 88.

leatherwood, mountain, 86.

legume family, 63.

Leguminosae, 63.

Lemaireocereus thurberi, 90.

Liliaceae, 26.

lily family, 26.

locust, New Mexican, 71, 72; southwestern, 72.

Lophocereus schottii, 91.

lotebush, 83.

lysiloma, littleleaf, 63, 63.

Lysiloma microphylla, 63; thornberi,

63; watsoni, 63.

madrone, Arizona, 95, 96; Texas, 95,

96.

madroño, Arizona, 96; Texas, 96.

manzana de puya larga, 57.
108 HANDBOOK NO. 9, U. S. DEPARTMENT OF AGRICULTURE

maple, bigtooth, 81, 81; dwarf, 80;

Rocky Mountain, 80, 81; western

sugar, 81.

maple family, 80.

mescalbean, 69, 70.

mesquite, 65; honey, 65; screwbean, 66;

velvet, 65, 65; western honey, 65,

65,

Moraceae, 54.

Morus microphylla, 54.

mountain-laurel, 78.

mountain-mahogany, birchleaf, 59, 60;

curlleaf, 58, 59; hairy, 59, 59;

Wright, 59.

mulberry, Mexican, 54; mountain, 54;

Texas, 54, 55.

mulberry family, 54.

Negundo interius, 80.

Nicotiana glauca, 101.

nightshade family, 101.

nogal, 42, 43.

nolina, Bigelow, 29, 30; Parry 30.

Nolina bigelovii, 30; bigelovii var,

parryi, 30; parryi, 30.

oak, Arizona, 47; Arizona white, 47,

J^7; black, 52; blackjack, 52; California scrub, 48; canyon live, 51;

chinquapin, 49, 50; Emory, 51, 52;

Gambel, 50, 51; gray, 47, 48; Mexican blue, 46, 47; netleaf, 46, 47;

Palmer, 51, 51; Rocky Mountain

shin, 49; Rocky Mountain white, 50;

scrub, 48, 49; shrub live, 48, 49; silverleaf, 51, 52; Tourney, 48, 49; turbinella, 48; Utah white, 50; wavyleaf, 49, 49.

Oleaceae, 98.

olive family, 98.

Olneya tesota, 72.

Opuntia acanthocarpa, 94; acanthocarpa var. thornberi, 94; fulgida, 92;

fulgida var. mammillata, 92; spinosior, 93; thornberi, 94; versicolor,

94.

Ostrya baileyi, 44; knowltoni, 44.

Padus valida, 61.

palm family, 24.

palma, 30.

Palmae, 24.

palmilla, 26.

paloblanco, 53.

palo de hierro, 72.

palo fierro, 72.

paloverde, blue, 69, 69; foothill, 68;

littleleaf, 68; Mexican, 67; yellow,

68, 69.

Parkinsonia aculeata, 67; microphylla,

68; torreyana, 69.

Picea engelmanni, 17; parryana, 17;

pungens, 17.

pigeonberry, 84.

Pinaceae, 10.

pine. Apache, 15, 16; Arizona, 15; Arizona longleaf, 16; Arizona ponderosa, 15; Arizona yellow, 15; border

limber, 13; bristlecone, 11, 13; Chi

huahua, 14, i5; Colorado pinyon, 11;

foxtail, 13; limber, 13, 15; Mexican

pinyon, 10; Mexican white, 13; nut,

10, 11, 12; Oregon, 18; pinyon, 10,

11; ponderosa, 15; Rocky Mountain

ponderosa, 15; Rocky Mountain

white, 13; singleleaf pinyon, 12;

western yellow, 15; white, 13; yellow, 15.

pine family, 10.

Pinus apacheca, 16; aristata, 13; arizonica, 15; brachyptera, 15; cembroides, 10; cembroides var. edulis,

11; cembroides var. monophylla, 12;

chihuahuana, 14; edulis, 11; flexilis,

13; flexilis var. reflexa, 13; latifolia,

16; leiophylla var. chihuahuana, 14;

monophylla, 12; ponderosa, 15, 15;

ponderosa var. arizonica, 15; ponderosa var. scopulonim, 15; strobiformis, 13.

pinyon, 11, 11 ; Mexican, 10,11 ; singleleaf, 11, 12.

pitahaya, 90; dulce, 90.

planetree, Arizona, 54.

Platanaceae, 54.

Platanus racemosa var. wrightii, 54;

wrightii, 54.

plum, American, 61, 62; wild, 62.

poplar, Fremont, 33; narrowleaf, 31;

plains, 34; Rio Grande, 34; trembling, 32.

Populus acuminata, 32; angustifolia,

31; aurea, 32; fremontii, 33; fremontii var. wislizeni, 34; sargentii,

34; tremuloides, 32; tremuloides var.

aurea, 32; wislizeni, 34.

Prosopis glandulosa, 65; juliflora, 65;

juliflora var. glandulosa, 65 ; juliflora

var. torreyana, 65 ; juliflora var. velutina, 65; odorata, 66; pubescens,

66; velutina, 65.

Prunus americana, 62; emarginata, 60;

emarginata var. crenulata, 60; rufula, 62; virens, 62; virens var. rufula, 62; virginiana, 61; virginiana

var. demissa, 61; virginiana var.

melanocarpa, 61.

Pseudotsuga douglasii, 18; mucronata,

18; taxifolia, 18; taxifolia var.

glauca, 18.

Ptelea angustifolia, 73, 74; angustifolia var. cognata, 74; pallida, 73.

Quercus arizonica, 47; chrysolepis var.

palmeri, 51; diversicolor, 46; dumosa

var. turbinella, 48; emoryi, 52; gambelii, 50; grisea, 48; gunnisonii, 50;

hypoleucoides, 52; leptophylla, 50;

muehlenbergii, 50 ; novomexicana,

50; oblongifolia, 46; palmeri, 51;

reticulata, 46; submollis, 50; subturbinella, 48; tourneyi, 48; turbinella,

48; undulata, 49; utahensis, 50; wilcoxii, 51.

quinine-bush, 58.
SOUTHWESTERN TREES 109

redbud, Arizona, 67; California, 65, 67;

western, 67.

redcedar, Rocky Mountain, 22.

retama, 67.

Rhamnaceae, 83.

Rhamnus betulaefolia, 85; betulaefolia

var. obovata, 85; califomica var.

ursina, 84; crocea var. ilicifolia, 84;

ursina, 84.

Rhus choriophylla, 78; kearneyi, 78;

ovata, 78.

Ricinus communis, 76.

Robinia neo-mexicana, 72; neo-mexicana var. luxurians, 72; neo-mexicana var. subvelutina, 72.

Rosaceae, 55.

rose family, 55.

rosewood, Arizona, 55.

rue family, 73.

Rutaceae, 73.

saguaro, 88, 91.

Salicaceae, 31.

Salix amygdaloides, 37; amygdaloides

var. wrightii, 37; bebbiana, 41; bonplandiana, 36; bonplandiana var.

toumeyi, 36; caudata var. bryantiana, 35; exigua, 38; exigua var,

nevadensis, 38; exigua var. stenophylla, 38; gooddingi, 36; interior,

39; interior var. angustissima, 39;

laevigata, 36; lasiandra, 35; lasiolepis, 40; ligulifolia, 40; lutea, 40;

lutea var. ligulifolia, 40; nigra var.

vallicola, 36; rostrata, 41; scouleriana, 41; taxifolia, 39; wrightii, 37.

salt-cedar, 86.

Sambucus cei-ulea, 104; cerúlea var.

arizonica, 103; cerúlea var. mexicana, 103; glauca, 104; glauca var.

arizonica, 103 ; glauca var. velutina,

104; mexicana, 103; neomexicana,

104; velutina, 104.

Sapindaceae, 82.

Sapindus drummondi, 82; saponaria

var. drummondi, 82.

sapium, jumping-bean, 77, 77,

Sapium biloculare, 77.

Sapotaceae, 97.

sapote family, 97.

sauco, 103.

screwbean, Fremont, 65^ 66,

Senegalia greggii, 63.

senita, 91, 91.

serviceberry, Utah, 56, 57.

shinnery, 49.

Simaroubaceae, 74.

slippery-elm, California, 86.

smokethorn, 71, 71.

smoketree, 71.

soapberry, western, 81, 82,

soapberry family, 82.

soapweed, 26.

Solanaceae, 101.

sophora, mescalbean, 70.

Sophora secundiflora, 70.

spruce, blue, 17, 19; Colorado, 17;

Colorado blue, 17; Engelmann, 17,

19; mountain, 17; silver, 17; white,

17.

spurge family, 76.

sugarbush, 78.

sterculia family, 86.

Sterculiaceae, 86.

Strombocarpa odorata, Q^; pubescens,

sumac, Kearney, 78, 79; Meams, 78,

79; sugar, 78, 79.

sycamore, Arizona, 54, 55.

sycamore family, 54.

Tamaricaceae, 86.

tamarisk, athel, 87; French, 86, 87.

tamarisk family, 86.

Tamarix aphylla, 87; articulata, 87;

gallica, 86.

tasajo, 93, 93.

tesota, 71, 72.

tobacco, tree, 101, 101.

tornillo, 66.

torote, 76.

tree-of-heaven, 75.

Ulmaceae, 53,

uña de gato, 63.

Vachellia farnesiana, 64.

vauquelinia, Torrey, 55, 55.

Vauquelinia californica, 55.

walnut, Arizona, 43, JÍ3; Arizona black,

43; little, 42, J^; Texas black, 42.

walnut family, 42.

washingtonia, California, 24, 25.

Washingtonia filamentosa, 24; filifera,

24.

washington-palm, California, 24.

white-thorn, 65.

wild-olive, 101.

willow, acequia, 38; almond, 37; arroya, S9, 40; basket, 38; beaked, 41;

Bebb, 41, 1^3; black, 41; Bonpland,

36, 37; coyote, 38, 39; Dudley, 36;

fire, 41; Goodding, 36, 37; mountain,

41; Pacific, 35, 35; peach, 37; peachleaf, 37, 37; polished, 36; red, 35,

36; sandbar 38, 39; Scouler, 41, 1^3;

southwestern peach, 37; strapleaf,

40; Toumev, 36; western black, 35;

36; whiplash, 35, 35; white, 40;

Wright, 37, 37; Wright peachleaf,

37; yellow, 35, 39, 40; yew, 39; yewleaf, 39, 39.

willow family, 31.

yucca, datil, 30; hoary, 28; Joshua-tree,

27; Mohave, 29, 29; mountain, 28;

Schotts, 27, 28; soaptree, 26, 27;

Torrey, 29, 30.

Yucca baccata, 30; baccata var. macrocarpa, 30; brevifolia, 27; brevifolia var. jaegeriana, 27; elata, 26;

macrocarpa, 30; mohavensis, 29;

schidigera, 29; schottii, 28; torreyi,

30; verdiensis, 26.

Zizyphus lycioides, 83,

^ U.S. GOVERNMENT PRINTING OFFICE: 1972-478-316/329
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