1

Willows of Interior Alaska

Dominique M. Collet

US Fish and Wildlife Service

2004
2 Willows of Interior Alaska

Acknowledgements

The development of this willow guide has been made possible thanks to funding

from the U.S. Fish and Wildlife Service- Yukon Flats National Wildlife Refuge -

order 70181-12-M692.

Funding for printing was made available through a collaborative partnership of

Natural Resources, U.S. Army Alaska, Department of Defense; Pacific Northwest Research Station, U.S. Forest Service, Department of Agriculture; National

Park Service, and Fairbanks Fish and Wildlife Field Office, U.S. Fish and

Wildlife Service, Department of the Interior; and Bonanza Creek Long Term

Ecological Research Program, University of Alaska Fairbanks.

The data for the distribution maps were provided by George Argus, Al Batten,

Garry Davies, Rob deVelice, and Carolyn Parker. Carol Griswold, George

Argus, Les Viereck and Delia Person provided much improvement to the

manuscript by their careful editing and suggestions. I want to thank Delia

Person, of the Yukon Flats National Wildlife Refuge, for initiating and following

through with the development and printing of this guide.

Most of all, I am especially grateful to Pamela Houston whose support made the

writing of this guide possible.

Any errors or omissions are solely the responsibility of the author.

Disclaimer

This publication is designed to provide accurate information on willows from

interior Alaska. If expert knowledge is required, services of an experienced

botanist should be sought.
 3

Contents

Acknowledgements...............................................................................2

Introduction..................................................................................................6

Biology.............................................................................................................6

Ecology............................................................................................................6

Glacier-fed river gravel bars.......................................................................6

Flood plains........................................................................................................7

Uplands..........................................................................................................7

Bogs..................................................................................................................7

Treeline shrubs..................................................................................................7

Alpine tundra.....................................................................................................8

Human-modified habitats............................................................................8

Variations............................................................................................................8

Hybrids.................................................................................................................9

Usages....................................................................................................................9

Herbivores........................................................................................................10

How to use this guide.........................................................................11

Identification keys..........................................................................................11

Species descriptions.......................................................................................12

Insects and diseases.......................................................................................12

Maps..............................................................................................................13

Winter........................................................................................................17

Winter identification keys............................................................18

Winter description of willow shrubs and trees............................21

Felt-leaf willow, Salix alaxensis....................................................................21

Little-tree willow, Salix arbusculoides............................................................22

Barclay’s willow, Salix barclayi.......................................................................23

Bebb’s willow, Salix bebbiana..........................................................................24

Gray-leaf willow, Salix glauca.........................................................................25

Halberd willow, Salix hastata..........................................................................26

Sandbar willow, Salix interior..........................................................................27

Pacific willow, Salix lasiandra..........................................................................28

Barren ground willow, Salix niphoclada........................................................29

Park’s willow, Salix pseudomonticola.............................................................30

Diamond-leaf willow, Salix pulchra..........................................................31

Richardson’s willow, Salix richardsonii..........................................................32

Scouler’s willow, Salix scouleriana.................................................................33

Sitka willow, Salix sitchensis............................................................................34

Contents
4 Willows of Interior Alaska

Summer.......................................................................................................35

Flowering keys...........................................................................................36

Vegetative key............................................................................................39

Summer description of willow shrubs and trees.........................43

Felt-leaf willow, Salix alaxensis.................................................44

Little-tree willow, Salix arbusculoides......................................46

Arctic willow, Salix arctica............................................................48

Northern willow, Salix arctophila...............................................50

Athabasca willow, Salix athabascensis...................................................52

Barclay’s willow, Salix barclayi..............................................54

Barratt’s willow, Salix barrattiana...........................................................56

Bebb’s willow, Salix bebbiana..................................................58

Silver willow, Salix candida.......................................................................60

Chamisso willow, Salix chamissonis........................................................62

Alaska bog willow, Salix fuscescens........................................64

Gray-leaf willow, Salix glauca.................................................66

Halberd willow, Salix hastata....................................................68

Sandbar willow, Salix interior.................................................70

Pacific willow, Salix lasiandra....................................................72

Blueberry willow, Salix myrtillifolia.........................................74

Barren-ground willow, Salix niphoclada..................................76

Skeleton-leaf willow, Salix phlebophylla.................................78

Polar willow, Salix polaris.........................................................80

Park’s willow, Salix pseudomonticola............................................82

Tall blueberry willow, Salix pseudomyrsinites..........................84

Diamond-leaf willow, Salix pulchra.......................................86

Net-veined willow, Salix reticulata............................................88

Richardson’s willow, Salix richardsonii......................................90

Least willow, Salix rotundifolia................................................92

Scouler’s willow, Salix scouleriana...........................................94

Setchell’s willow, Salix setchelliana.........................................96

Sitka willow, Salix sitchensis...................................................98

Comparison of female catkins and pistils...........................102

Bibliography............................................................................................108

Useful information............................................................................110

Glossary......................................................................................................111
 5

Introduction
6 Willows of Interior Alaska

Introduction

This guide is written for biologists who need to identify willows used by

wildlife, for landowners and landscaping contractors who harvest willows for

riverbank erosion control projects, and for the naturalist in all of us who are

simply curious about the diversity of the environment.

Worldwide, 330 to 350 willow species have been described, mostly from

temperate and cold regions of the northern hemisphere. Of the 40 willow species

known to occur in Alaska, 29 species are found growing in the interior of

Alaska, in the area covered by this guide.

Willows are an important element of the vegetation above timberline and in

disturbed sites in the boreal forest or the floodplains. They are also an important

source of food for beaver, ptarmigan, moose and other herbivores.

The ease of propagation of some willows makes them ideal for environmental

rehabilitation projects in disturbed zones, such as roadsides and stream banks.

Restoration methods using willows and other plants are discussed at length in

Streambank Revegetation and Protection: a Guide for Alaska (Muhlberg and

Moore1998).

 .

Biology

Willows are unisexual, each individual plant bearing either male or female

flowers. These minute flowers, reduced to an ovary or a set of anthers adorned

with a scale and one or two nectaries emerging from their base, are crowded into

catkins. Fertilization is done by the wind or by visiting insects attracted to the

sweet secretions of the nectaries.

Riverine willows S. interior and S. setchelliana propagate mostly vegetatively

by producing shoots from roots and buried stems or by rooting severed twigs

buried in alluvium.

Ecology

Willows require full sun exposure to thrive. They colonize newly exposed

sediments of river alluvions, or sites where the original vegetation cover has

been removed, exposing the mineral soil, like the vast expanses of kindling-dry

boreal forest consumed every year by fires in interior Alaska. The minute willow

seeds, outfitted with long soft hairs that keep them aloft in the slightest breeze,

disperse over a broad area but carry few nutrients. Under the best conditions,

they remain viable only a few weeks and require moist bare mineral soil in full

sunlight for germination since they cannot compete against established plants.

Salix scouleriana in particular is quick to recolonize burned sites. Dwarf willows

are found only in sites where the general vegetation remains low to the ground

such as in subalpine and alpine sites.

Glacier-fed braided rivers

In the southern regions of the Alaskan interior, the volume of glacier-fed rivers

fluctuates greatly over time. Most of the year, the barren river floodplain appears

oversized for the trickle contained within narrow channels. But at flood stage,

swollen by the summer snowmelt at the headwaters, the silt-laden river overflows the narrow channels and floods the whole breadth of the valley flats. The
 7

poorly vegetated gravel bars offer little mechanical resistance to the rushing

current that churns the mud, undercuts banks, shuffles gravel and silt, and

reorganizes channels, uprooting any vegetation that stands in the way. Soon, the

river recedes back to the main channel, leaving the banks high and dry. The

gravel bars are colonized by resilient species, always on the move: shrubs and

trees are uprooted and rafted downstream. Salix alaxensis and S. setchelliana

thrive in this habitat with little competition except from cottonwoods (Populus

balsamifera) and yellow mountain avens (Dryas drummondii) mats and river

beauty (Epilobium latifolium).

Flood plains

Rivers originating from the remainder of the Alaskan interior drain extensive

basins exhibiting a continental climate characterized by low annual precipitation. High water usually peaks in early spring when the high waters fed by local

snowmelt, which are sometimes exacerbated by an ice blockage downstream,

temporarily spread onto the floodplain. Seasonal fluctuations of the water flow

is buffered by the delayed release of the water stored in remote wetlands. The

cresting waters do not have the destructive behavior of ephemerally rushing

glacier-fed rivers. Lush willows such as S. interior, S. alaxensis, and S. lasiandra

dominate on the freshly deposited sediments in this floodplain. These early

colonizers are followed by alders (Alnus viridis), birches (Betula papyrifera)

and poplars intermixed with extensive thickets of S. barclayi, S. richardsonii, S,

pseudomonticola, S. alaxensis, S. arbusculoides, S. glauca or its diminutive S.

niphoclada.

Uplands

Few willows survive the low light conditions under the dense canopy of the

mature boreal forest dominated by white spruce (Picea glauca) and paper birch

on well drained lands, above the floodplain and river terrace. Where enough

light reaches the shrub layer, either in disturbed sites or at the edge of the forest,

shrubby willows are well represented by S. bebbiana, S. scouleriana, S. glauca,

S. alaxensis, and S. arbusculoides. But when the forest canopy is disturbed by a

catastrophic event such as a fire, the same willows, along with alders, fireweeds,

legumes, and grasses, are quick to get established. Over time, hardwoods and

conifers overshadow the willow shrubs unless recurrent disturbances or poor

growing conditions prevent trees from establishing.

Bogs

Most willows favor moist sites, and the genus is well represented by S.

pulchra, S. fucescens and S. myrtillifolia in wetlands, both at the margin of

acidic muskegs and in more productive sites, such as lake shores and riverbanks.

Many species of willows favor sites that are seasonally flooded. Plants living in

muskegs and fens remain stunted, barely topping the grasses and sedges.

Treeline shrubs

In the mountains above treeline, S. barclayi south of the Alaska Range, S.

pulchra, S. niphoclada, S. richardsonii, S. glauca, and S. arctica everywhere

form extensive treeline thickets. Willows are especially lush in hollows drained

Introduction
8 Willows of Interior Alaska

by creeks. Thick snow cover protects these willows from the rigors of winter and

heavy browse by moose.

Alpine tundra

The treeline thicket species described above also occupy higher sheltered

pockets of the alpine zone, as long as reliable sources of moisture and protection

from the elements are available. Exposed mountain ridges are home to dwarf

willows such as S. arctica, S. polaris, S. phlebophylla, and S. rotundifolia whose

stems and leaves hug the rocky substrate.

Human-modified habitats

Under natural conditions, open habitats result from disturbance events like

forest fire, avalanche, flood, and insect infestation, or the retreat of a glacier.

Modification of the landscape by humans creates new opportunities for willows

to invade sites that otherwise would be densely forested. On highway right-ofways regularly cleared by HydroaxeTM tractors, colonizing willow thrive. The

ubiquity of these willow thickets along right-of-ways is due to the repeated

mowing that prevents the establishment of trees, including arborescent willows.

Willow seedlings readily establish also in lawns not treated with dicot-specific

herbicides: a few leaves close to the ground survive repeated mowing and feed a

root system that will give the plants a head start, should the mowing be interrupted.

Variations

Most willow species vary greatly according to their growing conditions. This

variation can be so great that, at first glance, distinct species within a thicket

resemble each other more than specimens of their own species growing under

different conditions. Leaf shape, size, plant stature, color, and texture can vary

greatly, whereas catkin and pistil characteristics remain fairly constant. Slow

growing, undisturbed, and unbrowsed “mature” willows usually have small, stiff

leaves and show

reduced yearly

stem elongation.

The branchlets

develop nodes at

the site of leaf

attachments and

appear knobby.

Vigorous growth of

willows in disturbed habitats, on

the other hand,

typically produce

long annual stems

with leaf buds

widely separated.

Willow species

that reach tree-size

at maturity, such as Salix scouleriana

Canopy leaf

Sucker leaf
Introduction 9

S. scouleriana, S. lasiandra or S. alaxensis, first produce long unbranched stems

that later develop into single or multiple trunks. With maturity, the yearly

elongation slows down and branching increases to form the canopy.

In muskegs, the acidic nature of the soil limits the availability of nutrients and

allows only stunted growth. Slow-growing muskeg willows tend to branch at

ground level and be intertwined with the grasses and sedges that share the

habitat.

Snow cover protects the branches of alpine willow thickets from winter

abrasion and desiccation. The new annual growth is mostly limited to the

replacement of dieback and browsed branches. Individual stems die off after a

few years and are replaced by new shoots emerging from the root crown.

Plants rooted in rich soil whose above-ground parts have been trimmed

produce vigorous compensatory growth shoots, bearing large leaves. The fastgrowing S. barclayi, which thrives on highly disturbed road right-of-ways at low

elevations, appears quite different from its slow-growing kin at treeline.

Hybrids

Willows are infamous for hybridizing. The hybrid plant, besides having

characteristics intermediate between parent species, can also be noticed by

misshapen or aborted catkins. Hybridization appears to be more common in

regions where habitats have been extensively modified by human activities. In

Alaska, this does not (yet) appear to be a major problem for identification,

because only a very small percentage of specimens appear to be hybrids. In my

experience, less than 1% of the willows collected showed evidence of hybridization.

Usages

Because so many species are well adapted to human-modified habitat, willows

have always been an important part of the human landscape in North America,

Europe, and northern Asia. Willow foliage is good fodder for cattle, goats, and

horses, as well as for wildlife.

“Wickers” or “osiers,” the previous year’s growth of one-to-four meter long

willow suckers, are prime material for the manufacture of utilitarian objects.

Amerindian craftsmen in North America and gypsies in Europe wove willow

baskets, furniture, and other items, such as beehives, crab pots, snowshoes, and

fish traps. At the beginning of the industrial age, upward to 350 cultivars had

been developed in France, each with their own mechanical and esthetic properties. Today, although mostly replaced by objects molded out of plastics and other

synthetic materials, wickerworks are still manufactured for specialty items, such

as hot air balloon baskets, and to some extent, specialty baskets and outdoor

furniture.

The soft wood of willow is good for carving and makes good quality artist’s

charcoal. In Alaska, diamond willows (see p. 14) are carved into beautiful

walking sticks, furniture, decorative balusters, and posts. For fuel, S. bebbiana is

prefered to S. scouleriana. Salicin, the chemical that preceded acetylsalicylic acid (aspirin), was first

isolated from willow. The bark of some willow species is rich in tannin used for

the processing of leather. The primary use of willows today, however, is for

reclamation of disturbed sites and stabilization of riverbanks.

In Great Britain and Scandinavia, where fossil fuels are expensive, there is a
10 Willows of Interior Alaska

developing interest in willows as a source of renewable energy; the fast growing

shoots are coppiced (harvested) every few years, and the dried chips are sent to

electric power plants. This fuel burns clean, leaves little ash, and emits carbon

less than or equal to that absorbed from the atmosphere by the willow during

growth.

Known usage of specific willows is mentioned in each species description that

follows in this guide.

It should be mentioned that in Australia,where they are not native, willows

introduced for their abilities to stabilize riverbanks for bank stabilization, have

spread unchecked and locally displace the native vegetation. It was observed

there that seeds can be carried by the wind for more than 1 km and some travel

50 or even 100 km. Dispersion occured also through rooting of broken twigs in

favorable habitats.

Herbivores

The foliage of most willow contain salicilin, a chemical (phenolic glycoside)

that deters browsing by most generalist herbivorous insects and mammals. Only

a small fraction of the diet of these herbivores, such as the snowshoe hare (Lepus

americanus) can consist of willows because the salicin distresses the digestive

tract just as aspirin (methyl salicylate) does when taken on an empty stomach. A

few generalist herbivores, like the moth Orgia antiqua, are able to complete their

development on willow alone.

Specialized herbivores, like moose (Alces alces) and to a lesser degree caribou

(Rangifer tarandus), cope well with these chemicals in their browse and are able

to tap this otherwise little used resource. For a few specialist herbivorous insects

such as sawflies (Tenthredinidae) and leaf beetles (Chrysomelidae), the volatile

phenolic glycoside even serves as feeding and oviposition cues.

Herbivores that do not feed on willow may still depend on the plants for

shelter or for the microhabitat they create. This results in a compartmentalization

of the fauna in willow-rich habitats: a majority of herbivorous species avoids

feeding on willows while a small fraction is totally dependent on them.

Only a few species of willows found in Alaska have been tested for their

salicilin content. Salix scouleriana, S. arbusculoides, and S. lasiandra contain

the secondary compound, while S. sitchensis does not. Salix barratiana is one of

the most bitter tasting, while S. alaxensis and S. pulchra are the least bitter. The

young leaves of the last two species can even be harvested for human consumption in the spring.

The sweet nectar of the early flowering willows provide most of the needed

energy for the bumblebees that are active before the snow has melted away.

Among vertebrates, several species of ptarmigan (Lagopus) and grouse feed on

the buds during winter, and mammals like beaver (Castor candensis), musk oxen

(Ovibos moschatus), Arctic ground squirrel (Spermophilus parryii), lemmings,

and voles incorporate some willow, possibly species with low phenolic content,

into their diet.

The structure of particular willows determines the potential use of the plant by

specific herbivores: the dense woolly hairs covering the underside of leaves of

Salix alaxensis provide protective cover for Phratora leaf beetle larvae, but

prevent the willow leafblotch miner moth (Micrurapteryx salicifoliella) from

depositing her eggs. During the years 1991-1993 and1998-1999, the willow

leafblotch miner infested hundred of thousands of acres in theYukon and

Kuskokwim drainages (USDA Forest Service 2000). The 1998-1999 outbreak

was centered on the Yukon Flats National Wildlife Refuge. All willows but S.

alaxensis were heavily infested.
 11

How to use this guide

Descriptions of willow catkins and leaves requires the use of specialized names.

The usage of technical terms has been kept to a minimum in this guide:

Identification keys

During the growing season, willows with catkins can best be identified using

the flowering keys. If no catkins can be found on the plants, the vegetative key

based on stem and leaf characters can be used.

Because much research on wildlife browse and revegetation projects require

that willow be identified during the winter, an additional winter identification key

to willow shrubs is also provided.

To identify a willow using the keys, e.g. page 36 read the first pair of statements (1.a & 1.b) and choose which of the two best applies. For example if the

willow is a tall shrub, 1.b is chosen. The number 12 at the end the statement 1.b

leads to the pair of statements (12.a & 12.b). Repeating the process will lead to a

willow species by elimination. Look up the species description, check the habitat,

and the distribution map provided to confirm the identity of that willow species.

A hand lens magnifying 10 times or a dissecting microscope is required to

examine small structures of the catkins or leaves.

Male

catkin

Female

catkin

Male

floret

Female

floret

Leaf

Anther

Stamen

Midvein

Petiole

Nectary

Style

Ovary

Nectary

Stigma

Bract

Stipe

Leafed

branchlet

Pistil

Stipule

How to Use this Guide

Bract
12 Willows of Interior Alaska

Species descriptions

Scientific and common name

All plants and animals are given a unique scientific name composed of two

words written in italics. The first word, the genus name, is common to closely

related species. For example, both the domestic dog and the coyote have the

same genus name Canis, and the genus name of all the true willows is Salix. The

second word designates the species. Thus Canis familiaris is the domestic dog,

Canis latrans is the coyote, and Salix alaxensis is the felt-leaf willow. Common

names often vary regionally and are thus not reliable. For instance, Salix

alaxensis’ common name can be either “Alaska willow” or “felt-leaf willow.”

Sometimes the common name “willow” is used for non-willow species which

adds to the confusion. The fireweed, Epilobium angustifolium, is sometimes

referred to as the “willow herb.” For this reason, scientific names are used

throughout the guide, although a common name is given with the descriptions.

Identification

A brief description of the species is given with more details than the keys. The

most important diagnostic characteristics are written in bold.

Similar species

Diagnostic characters are compared with those of similar species.

Habitat

This information can help for identification because certain species are restricted

to well-defined habitat.

Wetland Indicator Status

 The National Wetland Inventory (U.S. Fish and Wildlife Service) publishes the

“National List of Plant Species That Occur in Wetlands, www.nwi.fws.gov/bha

that assigns a wetland indicator status to each plant species found in wetlands.

This describes the frequency of occurrence of an individual species in wetlands

versus non-wetlands. Only willows species that are considered wetland indicators in Alaska have been rated here:

Obligate Wetland (OBL): Almost always occurs in wetlands.

Facultative Wetland (FACW): Usually occurs in wetlands, but occasionally

found in non-wetlands.

Facultative (FAC): Equally likely to occur in wetlands or non-wetlands.

Facultative Upland (FACU): Usually occurs in non-wetlands, but occasionally

found in wetlands.

Phenology

This section describes the sequence in the development of the willow organs.

Usually, whether or not catkins and leaves develop at the same time is consistent

for each willow species. The timing of the development of the willow as a whole

is usually delayed with increased elevation. In mountain habitats, it is not

unusual to observe a willow with fully developed leaves and catkins a few feet

away from another willow of the same species still in winter bud, because it was

covered by a late melting snow drift.

Notes

General notes about the biology.

Uses

Traditional or modern use of the species.

Insects and diseases

Numerous insects species and diseases are known to be associated with willows.

A few common galls and diseases are illustrated pp. 14 -15.
How to Use this Guide 13

Leaf skeletonizers and browsers

Chrysomelidae: leaf beetles (Coleoptera). Adults and larvae skeletonize the

leaves of willow. (See p.14). Gonioctena spp. and Chrysomela spp. adults look

like lady bugs, orange with black spots or the reverse, black with orange spots.

Phratora spp. are dark metallic,black, green or purple. Orgya antiqua: tussock moth. (Lymantriidae: Lepidoptera). The hairy caterpillars

feed on leaves of willows and other shrubs. The reddish-brown male moths fly

during the day. The female moths are unable to fly because their wings are much

reduced.

Trichiosoma triangulum: cimbicid sawfly (Cimbicidae: Hymenoptera). The

caterpillar-like larvae feed on willow leaves; the adults resemble black bumblebees.

Stem borers

Dorytomus: snout beetle (Cucurlionidae: Coleoptera). The minute larvae bore

willow buds or stems.

Saperda concolor: Long-horned beetle (Cerambycidae: Coleoptera). The larvae

bore galleries in large stems.

Thrypophleus striatulus: willow bark beetle (Scolytidae: Coleoptera). The minute

larvae bore under the bark of stems and trunks.

Gall inducers

Rabdophaga: gall midge (Cecidomyiidae: Diptera). Small flies that induce

“pinecone,” “beaked,” stem and “willow rose” galls on willow stems or buds.

Eriophyiidae: minute mites that induce “pouch galls” on willow leaves. Iteomyia: gall midge (Cecidomyiidae: Diptera). Small flies that induce small “nipple galls” on willow leaves.

Phyllocolpa: sawfly (Tenthredinidae: Hymenoptera). Small wasp whose larvae

develop inside the fold of willow leaf margin.

Pontania: sawfly (Tenthredinidae: Hymenoptera). Small wasps that induce peaor bean-shaped galls on willow leaves.

Leaf miners

Micrurapteryx salicifoliella: (Gracillariidae: Lepidoptera). The minute willow

leafblotch miner larva tunnels inside the willow leaves, At low population density,

it causes browning or blotches on the leaves. During an outbreak, most of the

leaves are covered with these blotches and the damage is visible from an aircraft.

Diseases caused by microorganisms

Diamond willow: scarring of willow stem or trunk, following prior infection by

the fungus Valsa sordida, causes sharp contrasted coloration in the heartwood.

These diamond willows are highly prized for handicraft.

Powdery mildew: fungus Uncinula spp. Rust fungus: fungus Melampsora epitea. Orange powder masses on the leaves.

Tar spot: fungus Rhytisma salicinum. Black shiny spot on leaves.

Maps

The distribution maps cover the area characterized by a continental climate and,

for our purpose, defined as the area of Alaska north of the Alaska Range, south of

the Brooks Range, and east of the Nulato Hills. Each location on the maps are

based on specimens identified by botanists experienced with willows and include

the following collections: National Herbarium of Canada, Ottawa; University of

Alaska Museum Herbarium, Fairbanks; University of Alaska Anchorage Herbarium, and the author’s collection.
14 Willows of Interior Alaska

Salix lasiandra leaf

skeletonized by leaf

beetles

(Chrysomelidae)

“Diamond willow.” Heartwood

scarring following an infection

by the fungus Valsa sordida

Bark peeled

showing

decorative

color patttern

Rust fungus

Melampsora sp. on

underside of Salix

bebbiana leaf

Tar spot fungus

Rhytisma salicinum on

Salix barclayi leaf

Powdery mildew

Uncinula sp. on

Salix barclayi leaf
Common Willow Galls and Diseases 15

Rabdophaga rosaria

gall midge adult (4 mm)

Beaked gall induced by

Rabdophaga rigidae

Cross section

showing the

orange larva

“Willow rose”

induced by

Rabdophaga

rosaria on Salix

barclayi

Cross section

showing the

orange larva

Stem

swelling

induced by

Rabdophaga

salicis on

Salix barclayi Bud gall induced

by Rabdophaga

sp. on Salix

sitchensis

Euura sp. sawfly adult

 (4.5 mm)

Spindle gall

induced by

an unidentified

cecidomyiae on

Salix bebbiana

Cross section

showing

hollow cavity

Leaf bean galls induced

by Pontania sp. (sawfly)

on Salix barclayi

Pouch galls induced by eriophyiid

mites on Salix barclayi leaf

“Pinecone gall”

induced by

Rabdophaga

strobiloides on

Salix pulchra
16 Willows of Interior Alaska
 17

Winter
18 Willows of Interior Alaska

Winter key to the willow shrubs and trees of interior Alaska

This key is designed for the field identification of willows for wildlife browse

surveys and harvest of dormant stems used in revegetation projects. Only

willows reaching at least 1 meter in height are included in this key. Leaves and

catkins from the previous season often remain on dwarf shrub willows protected

under the snow cover and can often be identified with the summer or vegetative

keys.

The best technique for identifying willows at an unfamiliar site is to first look

for the obvious: dried catkins, leaves, petioles, or galls still attached to the

plants. Dried leaves or catkins found on the ground under a willow can be used

but with caution as they could come from other shrubs. Once a willow shrub is

positively identified, a voucher specimen should be collected, dried between

newspapers and labeled. A tag with the plant name should be left on the willow

from which the identified cutting was harvested and left in the field for future

reference. Confirmation of the identity can be done by rechecking the tagged

plant left in the field later in the season when the leaves or catkins are developed,

using the summer identification keys in this guide.

1.a Shrubs or trees with leaves shed or brown in winter; leaf scars arranged

alternately on the stems, winter bud covered by a single scale (see p.36).......2

1.b Not as above.............................................................................not a willow.

2.a Dried leaves, stipules, and/or catkins remaining on the plant......................3

2.b No leaf, stipule or catkin remaining on the plant.......................................15

3.a Persistent stipules (sometimes only a few) on either side of the previous

year’s leaf scar..............................................................................................4

3.b No persistent stipule......................................................................................8

4.a Stipules large, broad, leaflike, often numerous, giving the shrub a scraggly

appearance..................................................................S. richardsonii, p. 32.

4.b Stipules elongated, not leaflike....................................................................5

5.a Leaves underside woolly, young stems either covered with yellowish dense

hairs or coated with a bluish bloom such as found on grapes or plums............

.........................................................................................S. alaxensis, p. 21.

5.b Leaves underside not woolly.........................................................................6

6.a Catkin buds large, black and shiny with elongated tip, opening early in the

spring; leaf buds small, not shiny, more or less hairy; when present,

rosette gall with scales pointed at the tip and long white silk toward the

center, “pinecone gall” scales hairless.................................S. pulchra, p. 31.

6.b Catkins and leaf buds small, obscured under dense hairs, dried catkins often

present; “pinecone gall” scales white hairy ..................................................7
 19

7.a Catkins remaining on the plant.....................................................................8

7.b No catkins, but dried leaves on the plant ....................................................9

8.a Stipes long, catkins loose, pale yellow or light brown, curled........................

............................................................................................ S. bebbiana, p. 24.

8.b Stipe absent or minute, catkins compact,.....................................................10

9.a Shrubs usually less than 2 m, female catkins to 50 mm long, capsules to 6

mm long, male catkins often remain on the shrub overwinter. Rosette galls

up to 18 mm long........................................................ S. niphoclada, p. 29.

9.b Shrubs to 6 m, catkins to 80 mm long, capsules to 9 mm long, male catkin

rarely present on the shrub in winter. Rosette galls 10-40 mm long.............

............................................................................................... S. glauca, p. 25.

10.a Stem tips thin, whiplike, leaves long and narrow, often curled lengthwise,

margin finely toothed, underside covered with short stiff reddish hair

....................................................................................S. arbusculoides, p. 22.

10.b Stem tip thicker, leaves broader, no short red hairs covering the leaf under

 sides...........................................................................................................11

11.a Leaf underside woolly, petioles sometimes inflated, young stems either covered with yellowish dense hairs or coated with a bluish bloom such as

found on grapes or plums...................................................S. alaxensis, p. 21.

11.b Leaf underside not woolly, stems different than above.................................12

12.a Leaf margin toothed, leaves pale underneath and dark above.......................

...............................................................................S. pseudomonticola, p . 30.

12.b Leaf margin untoothed, leaf color variable.................................................13

13.b Buds scale visible, basal sections of some of leaf petioles remain attached to

the stem,..............................................................................S. hastata, p. 26.

13.a Bud scale obscured by dense hairs.................................................................14

14.a Shrubs usually less than 2 m. Leaves narrow, rounded at the tip, petiole to

3 mm long. Rosette galls up to 18 mm long.................S. niphoclada. p. 29.

14.b Shrubs to 6 m, leaves broader, tip often pointed, petioles 3-10 mm long.

Rosette galls 10-40 mm long............................................... S. glauca, p. 25.

15.a Stem tips thin, whiplike.............................................S. arbusculoides, p. 22.

15.b Stem tips thicker.........................................................................................16

Winter Identification Key
20 Willows of Interior Alaska

16.a Young stems either covered with yellowish dense hairs or coated with a

bluish bloom such as found on grapes or plums................S. alaxensis, p. 21.

16.b Not as above................................................................................................17

17.a Stem erect, newly established sandbars or disturbed habitat near major stream

or river. Early pioneer............................................................S. interior, p. 27.

17.b Stem branched. Various habitats.................................................................18

18.a Tree with distinct trunk and canopy; when still young, shoots with long

annual growth.................................................................................................19

18.b Shrub branching from the base......................................................................20

19.a Catkin buds black, not shiny, roundish and pointed at the tip, much larger

than leaf buds, developing in late winter, exposing the white catkin silk;

stems often branching at right angle, trunk bark grey, smooth ..................

.........................................................................................S. scouleriana, p. 33.

19.b Catkins and leaf buds alike, waxy to the touch, yellow or brown, oval,

shiny, developing in the spring; young stem waxy, branching at sharp angles,

trunk bark rough, deeply furrowed .................................S. lasiandra, p. 28.

20.a Young stems reddish-brown...........................................................21

20.b Young stems not reddish brown. Mostly south of the Alaska Range.............

............................................................................................S. barclayi, p. 23.

21.a Catkin buds flattened dorsoventrally (duckbill shaped) in the winter, fuller

but with a lateral pleat in the spring. Rosette gall with few deformed leaves.

Only south of the Alaska Range.......................................S. sitchensis, p. 34.

21.b Not as above.............................................................................................. 22

22.a Catkin buds much larger than leaf buds...............S. pseudomonticola, p. 30.

22.b Catkin buds almost the same size as leaf buds.............................................23

23.a Stems branching often at wide angle, common in disturbed sites, heavily

browsed by moose, catkin bud minute, pointed at the tip, minute

rosette...............................................................................S. bebbiana, p. 24.

23.b Stem branching at sharper angles, catkin buds not as above......................24

24.a Basal sections of some of leaf petioles remain attached to the stem;...........

stem densely hairy..................................................................S. hastata, p. 26.

24.b Basal section of petiole does not remain attached to the stem..................

..........................................................................S. pseudomyrsinites, p. 84.
 21

Salix alaxensis

Felt-leaf Willow

Tall shrub or tree up to 10 m tall.

Stems elongate up to 1.5 m in one season, coated with whitish bloom

or woolly; often a few persisting leaves, upper side reddish-brown glossy

contrast with densely woolly off-white underside; stipules elongated;

petioles sometimes inflated enveloping a winter bud; catkin buds start developing in winter; bud scale does not split at the tip but detaches from the base,

revealing the white silk catkin, leaf buds much smaller than catkin buds.

Wetlands, alpine meadows, and young forest.

Upperside of leaf

drying reddish-brown,

underside woolly

Petiole

sometimes

inflated

Young stems covered by

white waxy powder (bloom)

or by dense yellowish hairs

Leaf bud much

smaller than catkin bud

Catkin bud

scale detaches

from the base

Winter Descriptions
22 Willows of Interior Alaska

Tips whiplike

Catkin bud

minute

Salix arbusculoides

Little-tree Willow

Shrub 3 to 5 m tall.

Thin whiplike twig tips; catkin buds and leaf buds minute;

dried leaves elongated, curled, finely toothed at the margin, hairy underneath.

The leaves dry reddish brown and tend to curl up tightly. Large reddish brown

“pinecone” galls often develop on fast-growing shoots in disturbed habitat. Thin

stem below the pinecone gall sometimes twists.

 Openings in the boreal forest, muskegs, and willow thickets.

Leaf bud

minute

Leaf elongated,

toothed at the

margin

Underside

short silky
 23

Salix barclayi

Barclay's Willow

Shrub 1 to 2 m tall, many-branched from the base.

Leaves dry gray-black above, pale grey underneath; catkin buds

conical, elongate, diverging from the stem, slightly larger than leaf

buds; large dark gray-brown "willow rose" galls often numerous on fastgrowing shoots. Similar but reddish-brown "rose" galls also on S.

 commutata, and S. richardsonii. Very common shrub in moist sites along highways and disturbed sites south of

the Alaska Range. Also in drainage and gullies a higher elevations.

Forms extensive coastal and subalpine thickets associated with other willows.

"Rose” gall

Catkin bud conical

diverging from the

stem

Leaf

bud

Winter Descriptions
24 Willows of Interior Alaska

Salix bebbiana

Bebb's Willow

Erect shrub or small tree 1 to 8 m tall, branching from

low near the base, long unbrowsed stems and trunks

bowed, leaning, branches thin, drooping heavily; browsed stems short, erect,

contorted and knobby. Branches often inserted at right angles to the stem as for S.

scouleriana and S. commutata; bark of older trunk deeply furrowed. A few

characteristic catkins, light tan, loose because each capsule hangs from a long

stipe; often remain on female shrubs during winter. Winter buds small, shiny red,

or densely covered with white hair; catkin buds 3.5-5 mm long, only slightly

larger than the leaf buds 2.5-4 mm long; rosette gall very small, about 10 mm

long and diagnostic for the species; hollow stem gall sometimes on tips of fast

growing shoots, single-chambered with hole through the leaf petiole scar from

which the gall-inducing insect emerged.

Disturbed sites, open forest, in dry sites as understory, in wetlands and along

riverbanks. Fast-growing dark-red sucker shoots are very conspicuous in early

spring in cleared power line and road right-of-ways on well-drained soil.

Small red

leaf bud

Small red

catkin bud

Hollow stem gall

Small rosette

gall at tip of

fast-growing

sucker

Branching at right

angle to the stem

Emergence

hole
 25

Salix glauca

Gray-leaf Willow

Shrub 1 to 2 m tall.

Twigs and winter buds dull gray from the

dense hair cover; appearance of catkin buds

similar to leaf buds; female catkins, dried leaves, and sometimes dried stipules

remain on the shrub over winter; dried leaves tend to be curled end to end.

Pinecone gall, when present, with long white hairs on the scales.

Treeline thickets, lake shores, spruce-birch forest.

Salix niphoclada is very similar to S. glauca.

Leaf buds and

catkin buds alike

Elongated stipules

often present

Stems densely hairy

Winter Descriptions
26 Willows of Interior Alaska

Salix hastata

Halberd Willow

Shrub up to 4 m tall.

Branches flexible at the base with short, curved hairs. Catkin winter buds no

larger than leaf winter buds.

Willow thickets on floodplain, along creeks and lake shores and sand dunes, dry

tundra.

Catkin and leaf

buds similar

Base of leaf

petiole often

persisting

Short curved

hairs
 27

Salix interior

Sandbar Willow

Erect shrub up to 6 m tall, forming dense thickets on newly deposited alluvium.

Branches flexible at the base, branchlets yellow to brown. Catkin winter buds no

larger than leaf winter buds.

Catkin bud

Leaf bud

Winter Descriptions
28 Willows of Interior Alaska

Salix lasiandra

Pacific Willow

Tall erect shrub or tree up to 7 m tall and trunk up to 30 cm

in diameter. Trunk grayish-black, deeply furrowed, numerous

twigs sprouting for the whole length of the trunk; twigs feeling

wax-coated to the touch, brown or grayish green in midwinter,

yellow-green in spring; catkin buds slightly larger than leaf buds;

dried leaves grey, lance-shaped.

Banks of fast moving creeks, wetlands, and disturbed sites.

Catkin bud

Leaf bud

Stem

feeling

waxy to the

touch

Leaf lanceshaped
Winter Descriptions 29

Salix niphoclada

Barren GroundWillow

Shrub usually less than 1 m, but occasionally 3 m tall.

Catkins and bud leaves obscured by dense white hairs.

Stiff twigs and winter buds dull gray from the dense hair cover;

appearance of catkin buds similar to leaf buds; female catkins up to 50 mm long,

emptied in late winter.

Salix glauca is very similar to S. niphoclada.

Early sucessional on riverbanks.

Catkin and leaf

buds alike

Dense long

hairs

Stems stiff,

upright, branching

at sharp angles
30 Willows of Interior Alaska

Salix pseudomonticola

Park’s Willow

Shrub up to 6 m tall, many branched from the base.

Young stem reddish brown. Bark of stem older than 2 years with longitudinal

cracks. Outer layer along the split lift and appear yellow. Catkin winter buds

much larger than leaf winter buds. Catkins develop and open early in the spring.

River floodplain, opening in white spruce forest, bogs and fens.

Catkin

bud

Leaf

bud

Bark of 2 year

old stem splits

Catkin buds start

opening in late

winter

Margin

toothed

Pale

beneath
 31

Salix pulchra

Diamond-leaf Willow

Shrub 0.5 to 2 m tall, many-branched from the base.

Elongated dried stipules usually persisting several years on glossy red twigs;

catkin buds dark, shiny, and long-beaked, much larger than the leaf buds;

hairless catkin buds may develop and show some catkin silk as early as February; diamond-shaped leaves, reddish above, pale underneath with untoothed

margin often persisting; reddish-brown rosette gall, small (1-2 cm) with

pointed scales and long white silk at the center, diagnostic for the species when

present. Pinecone galls with scales hairless.

Riverbanks, wetlands, muskegs, moist alpine tundra.

Rosette gall

Pointed scales

Long silk

Long stipules

Catkin bud

much larger

than leaf buds

Leaf buds

Dark

shiny

Longbeaked

 Leaves red

hairless

diamond-shaped

Winter Descriptions
32 Willows of Interior Alaska

Salix richardsonii

Richardson's Willow

Shrub many-branched, 0.5 to 2 m tall.

Stem hairy, large dried leaflike stipules persist on the stem, giving a rough

appearance to the shrub; catkin buds develop early in the spring, much larger

than the leaf buds; leaves dry reddish brown.

Associated with other willows, forming thickets above timberline.

Large leaf-like

stipules

Stem hairy

Catkin bud

much larger

than leaf buds

Leaf bud
 33

Salix scouleriana

Scouler's Willow

Large erect shrub or tree up to 20 m tall. Usually several trunks

with new shoots arising from the root crown. Trunk bark gray,

smooth; branching often at right angles to the stem as for S.

bebbiana, but stouter and "knobby" from the enlarged leaf scars,

catkin buds round-oval with an elongated tip, not shiny, much

larger than leaf buds; catkin buds develop by midwinter, the bud scales remain

attached at the base but split open to the tip exposing the emerging catkin's white

silk, making this willow very conspicuous in late winter. Sometimes hollow stem

gall, with several communicating chambers at the end of stem, often with dried

leaves still attached. Similar galls on S. bebbiana have a single chamber, are in

the middle of the stem, and usually without attached dried leaves.

Common in mixed forest in the uplands and in disturbed sites.

Catkins open

in late winter

Scale

attached at

the base

Leaf bud

very small

Bud scars

knobby

Catkin bud

Winter Descriptions
34 Willows of Interior Alaska

Salix sitchensis

Sitka Willow

Shrub or small tree 1 to 8 m tall.

Stems from fast-growing suckers, shiny reddish-brown; slow-growing upper

canopy twigs knobby at the leaf scars, silvery gray, hollowed enlarged

parasitized buds divergent from the stem; catkin buds flattened on the back

like a duck bill early in the winter, fuller but still showing a lateral pleat later,

only slightly larger than the leaf buds that are blunt at the tip; terminal gall on

fast-growing shoots very characteristic; sometimes distinctive insect-induced

swelling on slow-growing twigs; underside of leaves and deformed leaves on the

terminal galls covered with short silvery hairs.

A coastal species, only found in the south of the area covered by this guide.

Disturbed sites and creekbanks in the forest zone.

Terminal

gall

Stem

swelling

induced by

insect

Silverygrey

Catkin bud

Leaf bud

Parasitized bud

divergent from

the stem

Silvery hairs

Slowgrowing

canopy

branch

Fastgrowing

shoot

Lateral

pleat

Blunt tip
 35

Summer
36 Willows of Interior Alaska

Poplar winter bud

covered by several

scales

Willow winter bud

covered by a

single scale

Flowering key to willows of interior Alaska. Adapted from Argus (2001).

Willows differ from other trees and shrubs by their leaves arranged alternately

on the stems, their winter bud covered by a single scale, and

their flowers bunched in dense catkins.

Use this key only if catkins are present; otherwise use the

vegetative key (p. 39). This summer key relies heavily on

female catkin characters. Individual willows are either male

or female and the female catkins themselves often remain

on the plant only for a short period. Occasionally, dried female catkins or dried leaves remain attached for an extended

period and can be useful for identification, but care must be

taken to make sure that they are still connected to the plant.

Willows of several species frequently grow side by side with

their branches entangled. Using dried leaves or catkins collected from the duff under the shrubs may mislead identification.

Catkins that appear before the leaves are usually directly

attached to the stems (see p.104) while those that develop

simultaneously with the leaves or later are borne on more or

less developed leafy branchlets (see p.106). The best way

to obtain a full set of characteristics for willows whose catkins and leaves are not present at the same time is to tag a

branch from which samples are collected at various times

of the year. Make sure that only cuttings from branches observed forking above ground are associated. The branch

samples labeled, pressed, and dried between newspapers can

be kept indefinitely.

1.a Dwarf willow with branches lying flat on the ground,

under 20 cm tall.................................................................................................2

1.b Upright shrub more than 20 cm tall or tree.........................................12

2.a Roundish leaves strongly veined, dark green above and pale beneath; reddish petiole long, at least half as long as the leaf blade............................

 ............................................................................... S. reticulata, p. 88.

2.b Leaf shape variable, veins not so conspicuous; petiole short................3

3.a Ovary hairy, sometimes only at the beak...................................................4

3.b Ovary hairless............................................................................................10

4.a Leaves finely toothed around the whole margin.........S. chamissonis, p. 62.

4.b Leaves margin untoothed or toothed only at the basal half......................5

5.a Leaves green beneath..............................................................................6

5.b Leaves pale beneath (pale waxy layer can be scraped with the fingernail

revealing green plant tissue beneath).......................................................7

6.a Leaf margin with a fringe of hairs; dried skeletonized leaves at the base

of the plants; plant with central root, stems spreading..................................

.....................................................................S. phlebophylla, p. 78.
 37

6.b Leaf margin hairless; dried leaves at the base of the plant not skeletonized,

plant spreading with roots at internodes..............................S. polaris, p. 80.

7.a Style 0-0.5 mm............................................................................................8

7.b Style longer than 0.5 mm..............................................................................9

8.a Ovary red, pear-shaped with short stiff reddish hairs; leaves hairless, dark

green glossy above, broadest near the tip; margin of the leaves toothed at

the base; flexible branches trailing in the vegetation....S. fuscescens, p. 64.

8.b Ovary grayish-green, barrel-shaped, densely white hairy; leaves elongated,

hairy above and beneath, margin not toothed; shrub erect, branches stiff,

grayish black hairy, dull (not shiny)..............................S. niphoclada, p. 76.

9.a Ovaries sparsely hairy with short flat crinkled hairs, leaf margin finely

toothed-glandular, leaves hairless, nectary shorter than the stipe...........

.........................................................................................S. arctophila, p. 50.

9.b Ovary densely hairy with straight hairs, leaf margin untoothed or only finely

toothed near the base; branchlets without roots; some of the leaves with

long silky hair forming a “beard” at their tip, nectary longer than the stipe

................................................................................................S. arctica, p. 48.

10.a Leaves green beneath, not fleshy..................................................................11

10.b Leaves pale beneath (pale waxy layer can be scraped with the fingernail

revealing green plant tissue beneath), fleshy...............S. setchelliana, p. 96.

11.a Plant minute, less than 5 cm high; leaves at most 1.5 cm long, roundish, not

toothed at the margin; female catkins short, bearing 4 to 15 pistils..............

........................................................................................S. rotundifolia, p. 92.

11.b Plant 10 cm high or more; leaves oval, more than 1.5 cm long, margin finely

toothed............................................................................S. myrtillifolia, p. 74.

12.a Catkins appearing before the leaves open, borne directly on the stem or on

short few-leafed branchlets........................................................................13

12.b Catkins appearing at the same time as the leaves open or later, borne on

developed leafy branchlets.........................................................................18

13.a Ovary hairless.............................................................................14

13.b Ovary hairy ............................................................................15

14.a Stipules well-developed, leaflike, persisting several years, young leaves

green, when present: Pontania-induced densely woolly bean-shaped leaf

galls 5-15 mm long.................................................. S. richardsonii, p. 90.

14.b Previous year’s stipules not present on the plant, new stipules rounded, young

leaves reddish: when present, Pontania-induced bald bean-shaped leaf gall

................................................................................S. pseudomonticola, p. 82.

15.a Leaves densely white woolly beneath, shiny bright green above..............

............................................................................................S. alaxensis, p. 44.

15.b Leaves not woolly beneath.............................................................16

Flowering Identification Key
38 Willows of Interior Alaska

16.a Leaves hairless beneath, shiny green above; stipules linear, persisting

several years on the stems..................................................S. pulchra, p. 86.

16.b Leaves hairy beneath, previous year’s stipules not persisting on the plant.

................................................................................................................... 17

17.a Low, dense shrub in wet subalpine thickets, stipules and buds oily, leaves

with long white hairs beneath.........................................S. barrattiana p. 56.

17.b Tall shrub or tree in forest zone, stipules and buds not oily, canopy leaves

with reddish hair appearing as a reddish hue; stipules not persisting several

years.........................................................................S. scouleriana, p. 94.

18.a Ovary hairless...............................................................................19

18.b Ovary hairy................................................................................23

19.a Leaves narrow, 6 or more times as long as wide, leaf margin finely toothed.

Sandbars on major rivers......................................................S. interior, p. 70.

19.b Leaves less than 5 times as long as wide, leaf edge toothed or not toothed.

Various habitats ........................................................................................20

20.a Leaves lance-shaped; 5 stamens in each male floret; leaf petiole glandular;

large shrub or small tree. Trunk bark blackish, deeply furrowed. Riverbanks

and wetlands ...................................................................S. lasiandra, p. 72.

20.b Leaves not lance-shaped; 1 or 2 stamens in each male floret; no glands on

the petiole. Bark variable. Various habitats ...........................................21

21.a Leaves green beneath ................................................................22

21.b Leaves pale beneath (pale waxy layer can be scraped with fingernail, showing green plant tissue) ........................................................S. barclayi, p. 54.

22.a Small shrub less than 1 m tall; flexible stems trailing in the vegetation,

leaves hairless; minute stipules 1-2 mm; style 0.3-0.5 mm...........................

........................................................................................S. myrtillifolia, p. 74.

22.b Erect shrub 0.5-4 m; stipules 1-5 mm; styles 0.3-0.5 mm....................

.............................. ................................................S. pseudomyrsinites, p. 84.

23.a Leaf underside densely white woolly, uncommon plant....S. candida, p. 60.

23.b Leaf underside not densely woolly............................................................24

24.a Reddish hairs scattered on both sides of the leaves especially on young

leaves........................................................................S. athabascensis, p. 52.

24.b No reddish hairs on the leaves....................................................................25

25.a Stipes 2-5 mm; catkins loose, often a few remaining on the shrub through

the winter; leaves upper side shiny, with veins impressed..............................

........................................................................................... S. bebbiana. p. 58.

25.b Stipe much shorter; catkins dense; veins not so conspicuous on the upper

side of the leaves...............................................................................26

26.a Leaves silky beneath. ......................................................................27

26.b Leaves hairy beneath, but not silky...............................................28
 39

27.a Leaves narrow, 5-7 times as long as broad, margin toothed, with a small

gland on each tip; 2 stamens in each male floret...... S. arbusculoides, p. 46.

27.b Leaves elliptic, less than 3 times as long as broad, leaves appear satiny

beneath (like the fur of a seal); 1 stamen in each male floret....................

.......................................................................................... S. sitchensis, p. 98.

28.a Petioles 3-15 mm long, yellowish. Subalpine thicket, lake shores...............

............................................................................................... S. glauca, p. 66.

28.b Petioles short, 1-3mm long, reddish. Coastal meadows and river sandbars

....................................................................................... S. niphoclada. p. 76.

Vegetative key to willows of interior Alaska.

 Adapted from Viereck and Little (1972).

1.a Dwarf shrub, mostly under 30 cm............................................................... 2

1.b Shrub taller than 30 cm or tree.....................................................................10

2.a Leaves toothed at least at their base...............................................................3

2.b Leaf margins not distinctly toothed................................................................4

3.a Leaf margin toothed at the base only, tip of leaves broad, leaves pale

beneath (pale waxy layer can be scraped with the fingernail revealing the

green plant tissue beneath).............................................S. fuscescens, p. 64.

3.b Whole leaf margins finely toothed, tip of the leaves pointed, underside

green............................................................................S. chamissonis, p. 62.

4.a Leaf veins with deeply impressed network on the upper side, long red

petiole.................................................................................S. reticulata, p. 88.

4.b Leaf vein not forming a deeply impressed network, petiole short, of various

colorations..................................................................................................5

5.a Leaves thick, fleshy like those of a “jade plant,” on barren glacier-fed river

sandbars and glacial outwash plain.............................S. setchelliana, p. 96.

5.b Leaves thinner, flexible, various habitats......................................................6

6.a Leaves pale beneath (pale waxy layer can be scraped with the fingernail

revealing the green plant tissue beneath).......................................................7

6.b Leaves green beneath.....................................................................................8

7.a At least some of the leaves with long silk hairs beneath forming a beard at

the tip of the leaves, branches stout, sparsely hairy..............S. arctica, p. 48.

7.b Leaves hairless, stems trailing, hairless.........................S. arctophila, p. 50.

Vegetative Identification Key
40 Willows of Interior Alaska

8.a Reddish-brown skeletonized leaves remain on the branches, leaf margin

with small hairs............................................................S. phlebophylla, p. 78.

8.b No skeletonized leaves remain on the branches, leaf margin hairless.........9

9.a Shrub densely matted, persisting dry reddish-brown leaves at the base of

the plant, leaves 0.4-1 cm long, with 3 prominent veins beneath...................

.......................................................................................S. rotundifolia, p. 92.

9.b Shrub loosely matted with long trailing stems, no persisting dried leaves on

the plant, leaves up to 2.5 cm long...................................... S. polaris, p. 80.

10.a Leaves densely woolly or felt-like underneath...............................................11

10.b Leaves hairy or not underneath but not felty or woolly...............................12

11.a Stipules 2-3 mm long, leaves 4-7 times as long as broad, branchlets densely

woolly, silvery in appearance. Uncommon in bogs of the upper Yukon and

upper tributaries.................................................................S. candida, p. 60.

11.b Stipules 4-20 mm long, leaves 2-4 times as long as wide, branchlets

densely yellowish woolly or hairless with bluish bloom. Some of the leaf

petioles often inflated in plants with woolly stems..........S. alaxensis, p. 44.

12.a Leaves pale beneath (pale waxy layer can be scraped with the fingernail

revealing the green plant tissue beneath).....................................................17

12.b Leaves green beneath...................................................................................13

13.a Leaves lance-shaped, broad at the base with an elongated tip. Tree with

rough blackish bark or shrub with long shoots................S. lasiandra, p. 72.

13.b Leaves of a different shape. Growth form variable......................................14

14.a No stipules or stipules minute.....................................S. myrtillifolia, p . 74.

14.b Stipules present............................................................................................15

15.a Low shrub usually less than 1 m tall, stout mostly unbranched stems, dense

foliage, buds and stipules oily, stems and leaves densely grey hairy..............

........................................................................................S. barrattiana, p. 56.

15.b Branching shrub usually taller than 1 m, foliage not so dense, stipules not

oily, stems and leaves not densely gray hairy...............................................16

16.a Leaves toothed at the margin...............................S. pseudomyrsinites, p. 84.

16.b Leaves toothless at the margin, petiole reddish, often short reddish hairs on

the main vein.........................................................................S. hastata, p. 68.

17.a Stipules minute or lacking............................................................................18
 41

17.b Stipules present (stipules fall off early in S. bebbiana)..................................22

18.a Leaves at least 6 times as long as wide, sandbars on major rivers...................

............................................................................................S. interior, p. 70.

18.b Leaves broader, various habitats..................................................................19

19.a Leaves densely covered underneath with short hairs, all oriented in the

same direction, appearing satiny (like the fur of a seal). Only south of

interior Alaska, riverbanks................................................S. sitchensis, p. 98.

19.b Underside of the leaves not satiny. Broader distribution..............................20

20.a Sparse reddish hairs on both sides of the leaves. Uncommon, in bogs............

....................................................................................S. athabascensis, p. 52.

20.b Only white hairs on leaves...........................................................................21

21.a Shrub mostly less than 1 m tall, leaves narrow, leaf hair sparse, straight

oriented toward the tip, petioles short...........................S. niphoclada, p. 76.

21.b Shrub or tree, leaves broad, leaf hairs curled, hairs mostly oriented in

various directions................................................................S. bebbiana, p. 58.

22a Stipules persisting several years on the stem...............................................23

22.b Stipules not persisting several years on the stem.........................................24

23.a Stipules linear, leaves elongated, diamond shaped, often dried reddish

leaves remaining on the shrub, Pontania-induced bald round leaf gall

3-10 mm long.......................................................................S. pulchra, p. 86.

23.b Stipules large, leaflike, remaining several years giving a coarse appearance

to the shrub, Pontania-induced densely woolly bean-shaped leaf galls 5-15

mm long .......................................................................S. richardsonii, p. 90

24.a Leaves lance-shaped, broad at the base with an elongated tip. Tree with

rough blackish bark or shrub with long shoots................S. lasiandra, p. 72.

24.b Leaves of a different shape. Growth form variable.......................................25

25.a Mature leaves hairless or hairy only on the main vein..................................26

25.b Mature leaves hairy.......................................................................................27

26.a Mature leaves hairless, stem tips stout, finely (densely) hairy stipules, leaf

like, asymmetrical, often numerous large blackish rosette galls, stem

variable. South of the Alaska Range..................................S. barclayi, p. 54.

26.b Mature leaves upper side with small red hairs on the main vein, (dissecting

microscope may be needed to see the small hairs), petiole reddish, stem tips

Vegetative Identification Key
42 Willows of Interior Alaska

thin, dark, shiny, leaves ending in a pointed tip, stipules mostly rounded.

Throughout Alaskan interior..............................S. pseudomonticola, p. 82.

27.a Upper surface wrinkled by creases caused by impressed veins, textured like

leather, leaf hairs long, curled..........................................S. bebbiana, p. 58.

27.b Upper surface plane, veins not impressed, leaf hairs not curled..................28

28.a Upper leaf surface shiny, hairs on leaf underside short, flat and reddish,

buds hairless or with few hairs.....................................................................29

28.b Hairs long and silky, buds densely hairy..............................S. glauca, p. 66.

29.a Leaves long, margin serrated, hairs densely hairy, reddish hairs underneath,

branch tips thin........................................................S. arbusculoides, p. 46.

29.b Leaves hairs not so dense, branch tips stout...............S. scouleriana, p. 94.
 43

Summer Willow Descriptions
44 Willows of Interior Alaska

Felt-leaf Willow

Salix alaxensis (Andersson) Coville

Identification

Summer: Shrub or tree up to 10 m tall. Underside of leaves densely felty

contrasting with green upperside; leaf stipule elongated; long female catkins

directly attached to the stem, upright to 14 cm long, developing early before the

leaves; ovary densely hairy; style long. Two varieties of Felt-leaf willow grow in Alaska:

Salix alaxensis alaxensis: branchlets densely covered with white-yellow woolly

hairs, leaf petioles often swollen, and the winter buds sometimes enlarged. This

variety of the Felt-leaf willow develops as a shrub up to 4 m tall.

Salix alaxensis longistylis: differs by the branchlets lacking woolly hairs. Instead,

the branchlets are coated with a fine white waxy powder (bloom) similar to

that found on fresh plums or grapes. The leaf petioles are rarely swollen and the

winter buds are often small. This variety may grow to tree size up to 10 m tall,

trunk diameter up to 30 cm.

Winter: see p. 21.

Similar species

Salix candida is the only other willow species with leaf underside densely

covered with woolly hairs. Salix candida, which is not common, differs from S.

alaxensis by flowering at the same time the leaves develop, the catkins borne on

leafy branchlets and by the elongated leaves less than 2 cm wide.

Phenology

At low elevation in the forest zone, S. alaxensis catkins appear mid-April to midMay; the female catkins start releasing seeds from mid-May to mid-June. The

leaves appear in early May and are fully developed by mid-June. In the alpine

zone above timberline, isolated S. alaxensis shrubs may start flowering as late as

mid-June.

Habitat

Feltleaf willow forms dense stands on

gravel bars of rivers with fast-flowing

water and grows associated with other

willows in wetlands, alpine meadows,

and young forest. It is one of the first tall

shrub species to colonize gravel bars of

glacier-fed rivers.

Wetland indicator status

Facultative.

Continued p. 100.
 45

Long style

Ovary

hairy

Leaf underside

densely woolly

Long

female

catkin

Catkins

develop

before the

leaves

Young

female

floret

Long

stipules

Male

catkin

Young

female

catkin

Male

floret

Summer Descriptions
46 Willows of Interior Alaska

Little-tree Willow

Salix arbusculoides Andersson

Identification

Summer: Shrub or small tree 1-6 m tall, occasionally to 10 m. Branches thin

and flexible; leaves elongated, 3 to 6 times as long as wide, hairless above,

silky below with short white or reddish hair oriented toward the leaf tip, margin

finely toothed; ovary densely silky. Fast growing shoots develop large lanceshaped leaves.

Winter: see p. 22.

Similar species

This is the only willow species with the combination of leaves more than 3 times

as long as broad with silky underneath surface and finely glandular-toothed

margin. Salix pulchra may have elongated leaves, but these are hairless underneath, without fine teeth at the margin, and the stipules remain on the stems for

several years.

Phenology

Catkins develop before or at the same time as the leaves, which are fully

developed as early as the end of May. The capsule releases its seeds by midJune.

Habitat

Openings in the boreal forest, muskegs, willow thickets in drainages in subarctic

tundra.

Wetland indicator status

Facultative Wetland.

Uses

This species is recommended for revegetation projects using the dormant

cuttings method. Moose browse this willow.

“Diamond willows” are sometimes formed on this species.

Insects and diseases

Euura sp., Micrurapteryx salicifoliella,

Pontania sp., Rabdophaga rigidae, R.

rosaria, R. strobiloides, eriophyiid mites,

and tar spot fungus.
 47

Leaves 3-6 times

as long as broad

Underside

silky-hairy

Silky

ovary

Margin

finely

toothed

Summer Descriptions

Male

floret

Male

catkin

Female

catkin
48 Willows of Interior Alaska

Arctic Willow

Salix arctica Pall.

Identification

Dwarf shrub growing prostrate against the ground or erect; oval leaves hairless

and shiny above, whitish underneath with long white hairs that form a beard

at the tip; catkins borne on leafy branchlets; female catkins long, manyflowered; ovary hairy; anthers purple; bract hairs long and straight.

Similar species

Usually, at least some leaves of S. arctica have long white hair on the

undersurface and margin forming a beard at the tip, undersurface whitish

whereas in S. rotundifolia, S phlebophylla, and S. polaris leaves are hairless, and

the leaf undersurface is green. Salix stolonifera and S. ovalifolia have hairless

ovaries. Specimens of S. arctica that lack the “beard” hair at the apex of leaves

and have no female catkins may be difficult to distinguish from S. stolonifera

and S. ovalifolia.

Phenology

Catkins develop at the same time as the leaves. The male and female catkins of

S. arctica appear from early June until mid-August, depending on the local

conditions in its natural subalpine or alpine habitat. Fully developed leaves can

be present as early as June.

Habitat

Alpine meadows, exposed mountain ridges, glacial river sandbars.

Uses

Salix arctica is the main diet for Arctic hares (Lepus arcticus), musk oxen and

collared lemmings (Dicrostonyx groenlandicus) in Greenland (Klein and Bay

1991).

Insects and mites

Chrysomelidae, Pontania sp., Rabdophaga salicis, and Eriophyiidae.

Note

Salix arctica hybridizes with S. barclayi

and S. stolonifera.
 49

Underside

pale

Silky

beard

Leafy

branchlet

Margin not

toothed

Ovary

hairy

Male

catkin

Female

catkin

Hairs

long and

straight

Summer Descriptions

Male

floret
50 Willows of Interior Alaska

Northern Willow

Salix arctophila Cock.

Identification

Dwarf shrub, often with long running branches; mature leaves hairless,

elliptic, margin untoothed, glossy yellow green above, whitish underneath.

Catkins developing at the same time as the leaves, on leafy branchlets; female

catkin long, erect; ovary reddish-purple, sparsely hairy with short flat crinkled

hairs, bract purplish or black with long straight hairs.

Similar species

Differs from S. arctica by the sparse flat, crinkled and refractive hairs on the

ovary while those on S. arctophila ovary are dense, or sparse but round in cross

section and non-refractive. Vegetative specimens may be difficult to separate

from S. arctica. Salix arctophila differs mostly by the absence of hair beneath

the leaves, and the long yellow-green branchlets often trailing.

Phenology

Catkins develop at the same time as the leaves.

Habitat

Wet tundra arctic or alpine tundra in the northeast of the area covered by this

guide.

Wetland indicator status

Obligate Wetland, Facultative Wetland.
Summer Descriptions 51

Illustrations to be completed

Male

floret

Female

catkin

Sparsely

hairy with

short

twisted

hairs

Whittish

underside

Creeping

branches

Leaves

hairless

 Leafy

branchlets

Long

straight

hairs
52 Willows of Interior Alaska

 Athabasca Willow

Salix athabascensis Raup.

Salix pedicellaris var. athabascensis (Raup) Boivin

Salix fallax Raup.

Identification

Shrub up to 1 m tall. Branchlets covered with curved hairs; leaf margin

untoothed, more or less covered with white or reddish hairs lying flat against

the surface of the leaf, stipules minute, catkins loosely flowered, bracts pale

brown, ovaries densely covered with long flat silks, stipe ± 1 mm long, nectaries

shorter than stipe.

Similar species

Difficult to identify, characteristic reddish hairs often sparse, or lacking. Separated from S. niphoclada by the longer stipes. Vegetative specimens lacking

reddish hair may be confused with S. niphoclada.

Phenology

Catkins develop at the same time as the leaves.

Habitat:

Fens, bogs, treed bogs. Not many locations known within the area considered by

the guide. May be overlooked.

Wetland indicator status

Obligate Wetland.
 53 Summer Descriptions

Female

catkin

Branchlets

covered

with curved

hairs

White or

reddish hairs

Catkin

loosely

flowered

Bract pale

brown

Stipules

minute

Long

flat silks

Stipe

± 1 mm
54 Willows of Interior Alaska

Barclay’s Willow

Salix barclayi Andersson

Identification

Summer: Shrub 1-2 m tall occasionally to 5 m, branching from the ground

level. Leaves develop at the same time as the catkins; mature leaves hairless,

green above, whitish underneath, margin more or less toothed, dry or bruises

gray-black; stipules broad, not persisting over winter; catkins borne on leafy

branchlet; ovaries pear-shaped, hairless. Often many large rosette galls,

especially in disturbed sites. Very common species from lowlands to subalpine

south of the Alaska Range.

Winter: see p. 23.

Similar species

Salix barclayi is not found north of the Alaska Range. Reports of specimens of

S. barclayi north of the Alaska Range usually are mis-identification of S.

hastata. Close examination will often reveal sparse reddish hairs on the main

leaf vein of S. hastata. Salix barclayi is variable in appearance but can be

distinguished from S. myrtillifolia and S. pseudomyrsinites by the leaf’s pale

underside, S. richardsonii and S. pseudomonticola by the catkins borne on welldeveloped leafy branchlets, appearing at the same time as the leaves. In the

subalpine, S. barclayi can be distinguished from S. richardsonii by their lack of

large dried stipules that persist several years on the stems.

Phenology

In the forest zone at low elevations, catkins and leaves start developing from

mid-May until mid-June, and the capsules start releasing seeds in mid-June. The

spent catkins drop at maturity.

In the alpine zone the development of catkins and leaves may be delayed as late

as mid-August by local snow conditions and may not mature every year.

Habitat

Salix barclayi is the dominant species in subalpine willow thickets and in moist

disturbed sites at lower elevations south of the Alaska Range. It reaches higher

elevations in moist gullies in alpine

habitats. Salix barclayi is very common

along road rights-of-way.

Wetland indicator status

Facultative.

Note

Hybridizes with S. arctica and S.

richardsonii.

Uses

This species is recommended for

revegetation projects using the dormant

cutting method.

Continued p. 100
 55

Pale

underneath

Stipules

broad

Color

variation

Ovary

pearshaped,

hairless

Male

catkin

Female

catkin

Catkins

develop

with the

leaves

Leafy

branchlet

Male

catkin

Margin

toothed

Summer Descriptions

Male

floret
56 Willows of Interior Alaska

Barratt Willow

Salix barrattiana Hook.

Identification

Shrub up to 1.5 m. Plant densely leafed, appears gray from a distance, characteristically standing out among other willows; oily stipules and buds, leaving

stains on the paper used to dry the specimens. Stems densely gray hairy, stipules leaflike, leaves crowded, long, gray hairy beneath, margin untoothed,

catkins long, appearing before the leaves, ovaries densely long hairy, with flat

hairs.

Phenology

Catkins appear before the leaves.

Habitat

Wet meadows, river gravelbars, and subalpine tundra.

Wetland indicator status

Facultative wetland.

Uses

Salix barratiana is very bitter and is avoided by most herbivores.

Insects and diseases

Pontania.
Summer Descriptions 57

Female

catkin

Male

floret

Leaves

crowded

Stems

densely

hairy

Catkins appear

before the

leaves

Densely

hairy

Hairs

flat

Dense

long

hairs
58 Willows of Interior Alaska

Bebb’s Willow

Salix bebbiana Sarg.

S. depressa L. subsp. rostrata (Richardson) Hiitonen

Identification

Summer: Upright shrub or tree to 10 m tall. Many-branched from the base,

lateral branches often inserted at right angles to the stems; upper surface of

mature leaves embossed with impressed veins, underside whitish, long wavy

white hairs on both surfaces: stipules falling off during summer; capsule stipes

long, female catkins loose; bracts tan-colored.

Winter: see p. 24.

When heavily browsed by moose, upright shrubs are scraggly-knotty looking.

Sucker leaves can be very large and have little likeness to usual canopy leaves.

Similar species

Salix scouleriana is also found on well-drained soil, with the branches often

inserted at right angles, and leaves are hairy on both sides; but the ends of the

canopy branches are stouter, the veins are not embossed on the upperside of the

leaves, the hairs on the leaf undersurface are short and flat, often reddish,

especially on the smaller leaves of the upper canopy. Salix bebbiana leaves are

usually distributed on the shrub from the ground up, while for S. scouleriana, the canopy leaves are usually out of reach without bending the branches

downward. Salix bebbiana has rough bark with ridges while S. scouleriana’s

gray bark is smooth. Les Viereck noted also that S. bebbiana wood is hard like

birch while S. scouleriana wood is soft and decays like aspen.

Phenology

Catkins appear from mid-June until mid-July, at the same time as the leaves

develop. The abundant yellow stamens of the male catkins and the grayish

female catkins appear simultaneously, making Bebb’s willow shrubs stand out

clearly against the background of the forest. The female catkins release seeds in

midsummer but often a few dried female catkins remain on the shrub over

winter.

Habitat

Bebb’s willow is a tall shrub in dry sites

as an understory of aspen, birch and

white spruce mixed forests; it is especially common near the forest edge, in

wetlands, and along riverbanks.

Wetland indicator status

Facultative.

Continued p. 100
 59

Long

stipe

Female

catkin

loosely

flowered

Catkins develop

with the leaves

Male

catkin

Ovary

hairy

Stipules

minute

Underside pale

with white wavy

hairs densely

wooly

Dull green with

impressed veins

Tancolored

bract

Margin

toothed

on large

leaves

Summer Descriptions

Male

floret
60 Willows of Interior Alaska

Silvery Willow

Salix candida Fluegge

Identification:

Less than 1 m tall, branchlets densely woolly; young leaves covered with feltlike material, petioles woolly, leaves narrowly elliptical, densely woolly

underneath, margin untoothed, ovary very densely woolly.

Similar species

In interior Alaska, only the leaves of S. alaxensis are woolly underneath but

those plants are usually much taller, the ovaries are covered with straight hairs,

the petioles are hairless, the stipules are elongated and often at least a few persist

more than a year on the twigs. Salix candida catkins appear at the same time as

the leaves and are borne on a leafy branchlet while S. alaxensis catkins are borne

directly on the stem.

Phenology

The catkins develop at the same time as the leaves.

Habitat

Fens, muskeg.

Wetland indicator status

Obligate Wetland.

Insects and diseases

Rabdophaga salicis.
Summer Descriptions 61

Male

floret

Female

catkin

Male

catkin

Densely

woolly

Densely

woolly

Petiole

woolly

Catkins

appear ast

the same

time as the

leaves
62 Willows of Interior Alaska

Chamisso Willow

Salix chamissonis Andersson

Identification

Dwarf shrubs less than 10 cm tall. Stems long, spreading. Stipules leaflike,

leaves oval or round, whitish beneath, hairless, upper surface shiny, hairless,

whole leaf margin toothed, ovaries hairy near the tip, with flat hairs.

Similar species

Salix chamissonis is distinguished from other dwarf willows by the leaves finely

toothed around the whole margin. The leaves of S. fuscescens are only toothed at

the basal half and leaves are broadest near the tip.

Phenology

Catkins develop at the same time as the leaves.

Habitat

Low shrub tundra, gravelly slopes and snow beds.
Summer Descriptions 63

Female

catkin

Stems

spreading

Margin

toothed

Flat

hairs

Whittish

beneath
64 Willows of Interior Alaska

Alaska Bog Willow

Salix fuscescens Andersson

Identification

Low creeping shrub, mostly hidden in grass, rooting from the stems; leaves

hairless, glossy green above, waxy white beneath, broadest near the tip,

narrowing toward the base, margin toothed near the base; no stipules; catkins on

long leafy branches develop at the same time as the leaves; ovaries long pearshaped, dark red and covered with short red hairs.

Similar species:

No other low-growing willow from interior Alaska has the combination of

smooth shiny leaves, broader near the tip and large pear-shaped and red-hairy

ovaries.

Phenology

At low elevations, catkins first appear in mid-May at the same time as the leaves

and release the seeds starting mid-July.

Habitat

Salix fuscescens is found in sedge fens and moist meadows, often growing

associated with S. barclayi, S. commutata, S. pulchra and S. myrtillifolia.

Wetland indicator status

Facultative Wetland.

Insects

Pontania sp., Rabdophaga rigidae, and R. rosaria.
 65

Male

catkin

Female

catkin

Pale

underneath

Broader

near the tip

Margin

toothed near

base only

Short white

or red hairs

Hairless

No

stipules

Glossy

green

Leafy

branchlet

Summer Descriptions

Male

floret
66 Willows of Interior Alaska

Gray-leaf Willow

Salix glauca L.

Identification

Summer: Shrub 0.3-1m tall. Stem bark with translucent layer often peeling off;

branchlets hairy; leaf upper surface dark green, underside densely white hairy,

tip more or less pointed, margins untoothed; yellowish petiole 2-15 mm long;

stipules elongate; densely flowered catkins borne on a leafy branchlet, leafy

branchlet of male catkin remains on the stem after the catkin falls; ovaries short,

densely woolly; styles 0.5-1 mm long; 4 long stigmas; bracts light brown, hairs

short and wavy; 2 nectaries, one on either side of the base of the pistil or

stamens.

Winter: see p. 25.

Similar species

Not always easily distinguished from S. niphoclada. Salix glauca leaves are

broader and are pointed at the tip, longer petioles, stipules, and stipes and is

typically found in the subalpine to alpine habitat, whereas S. niphoclada is

usually found in coastal wetlands. Hybridizes with S. arctica and S. niphoclada.

Phenology

Salix glauca is a late-flowering species. In the subalpine zone, depending on the

local late snow conditions, the catkins appear at the same time as the leaves from

mid-June until mid-August. The light brown mature female catkins remain on

the shrub over winter and the seeds are released the following spring.

Habitat

River flooplain and terraces, alpine tundra, edge of boreal forest, disturbed sites.

Common also following fires in black spruce stands and in mature black spruce

stands.

Wetland indicator status

Facultative.

Uses

Winter cuttings do not root well and are

not recommended for revegetation

projects.

Insects and mites

Euura sp., Micrurapteryx salicifoliella,

Pontania sp., Rabdophaga rigidae, R.

rosaria, R. salicis, R. strobiloides, and

Eriophyiidae.
 67

Catkins

develop

late

Female

catkins

Pale and

densely

hairy

underneath

Margin

untoothed

Petiole

yellowish

Leafy branchlet

Ovary

densely

woolly

Long dark stigmas

 2 nectaries

Stipule

linear

Hairs short

and wavy

Bract

pale

 2 nectaries

Summer Descriptions

Male

floret
68 Willows of Interior Alaska

Halberd Willow

Salix hastata L.

Identification

Shrub 1-3 m tall. Branches covered with short hooked hairs; leaf margins not

toothed, red hair persistent on upper surface midrib; ovaries reddish on very

short stipe, style sometimes forked.

Winter: see p. 26.

Similar species:

Resembles S. barclayi from which it differs by the presence of scattered reddish

hairs especially on the leaf midrib.

Phenology

Catkins develop at the same time as leaves.

Habitat

River floodplain, riverbank thickets, alpine sedge meadows.

Wetland indicator status

Facultative.

Insects

Rabdophaga rosaria.
 69

Catkins develop

with the leaves

Male

catkin

Female

catkin Short hooked

hairs

White or red hair

on midvein

Stipule

leaf-like

Ovary

hairless

2 stigmas fused

No stipe

Summer Descriptions

Male

floret
70 Willows of Interior Alaska

Sandbar Willow

Salix interior Rowlee

Salix exigua subsp. interior (Rowlee) Cronquist

Identification

Erect shrub up to 6 m tall, spreading by root shoots. Stipules minute or lacking,

leaves long and narrow, weakly whitish below, margin finely toothed or

glandular, tip pointed, bract beige, soon falling off after flowering; catkins long

and narrow on long leafy branchlets.

Winter: see p. 27.

Phenology

Catkins start developing at the same time as the leaves and keep flowering

through the warm season.

Habitat

One of the first species to get established on actively depositing alluvium, S.

interior forms almost pure stands on muddy sandbars flooded during high spring

water. As the water recedes, stems of S. interior emerging from the mud resemble mangroves at low tide.

Wetland indicator status

Obligate Wetland, Facultative Wetland.

Uses

In one site in the Tanana River floodplain,Wolff and Zasada (1979) report that S.

interior was favored over other willows by moose. This is unusual as moose

often appear to ignore this willow.

Insects

 Micrurapteryx salicifoliella, and Rabdophaga salicis.
Summer Descriptions 71

Male

floret

Female

catkin

Male

catkin

 Stipules

minute or

lacking

Margin

finely

toothed

Leaf long

and

narrow

Long leafy

branchlet

Bract falls

off after

flowering
72 Willows of Interior Alaska

Pacific Willow

Salix lasiandra Benth.

Salix lucida Muhl. subsp. lasiandra (Benth.) E. Murray

Identification

Summer: Shrub or tree up to 7 m tall. Old bark rough, blackish, and vertically

furrowed like the bark of cottonwood; young stems yellow-green, waxy; leaves

lance-shaped and rounded at the base, long pointed at the tip, green or sometimes reddish; two nectaries at the base of the flowers; 4-5 stamens for each

male flower; bract of female flowers drops off after flowering.

Winter: see p. 28.

Similar species:

At first glance, robust compensatory growth resembles cottonwood suckers. This

is the only willow species in Alaska with lance-shaped leaves, 4 or 5 stamens in

each male flower. Like S. interior, the bract of the female S. lasiandra flower

falls off after flowering.

Phenology

Catkins start developing in mid-May, maturing by the end of June. Leaves

develop at the same time as catkins.

Habitat

Wet habitat such as pond edges and fast-flowing stream banks. Salix lasiandra

appears early in succession and is able to keep up with the alders.

Wetland indicator status

Facultative Wetland.

Uses

This species is recommended for revegetation projects using the dormant

cuttings method.

Moose are very fond of this species.

Insects

Chrysomelidae, and Micrurapteryx

salicifoliella.
 73

Catkins develop

with the leaves

Male

catkin

Female

catkin

Pale

underneath

4 or 5 stamens

Bract falls

off after

flowering

Stem

waxy

Lance-shaped

Leafy

branchlet

Margin finely

toothed

Glossy

above

2 nectaries

Ovary

hairless

2 nectaries

Summer Descriptions

Male

floret
74 Willows of Interior Alaska

Blueberry Willow

Salix myrtillifolia Andersson

Identification

Low shrub 10-60 cm tall. Base of stems trailing and rooting, partially covered

by grasses and sedges, leaf underside green, hairless, leaf margin finely

toothed; stipules minute or leaflike, ovaries pear-shaped, hairless.

Similar species

Salix myrtillifolia can be distinguished from most shrubby willows by the green

leaf underside. Salix pseudomyrsinites and S. commutata undersides are also

green but their young leaves are hairy. The mature leaves of S. pseudomyrsinites

usually have at least a few hairs and S. commutata is distinctly hairy, with long

hairs on both sides of the leaves. Both are taller erect shrubs.

Phenology

At low elevation in the forest zone, the catkins and leaves start to develop in

mid-May and are fully developed by mid-July.

Habitat

Fens and muskegs, associated with dwarf birch (Betula nana), Labrador tea

(Ledum palustre), S. fuscescens, S. pulchra, and S. barclayi in the south.

Wetland indicator status

Facultative Wetland.

Insects and disease

Rabdophaga rigidae, R. rosaria, R. salicis, Eriophyiidae, and tar spot fungus.
 75

Catkins develop

with the leaves

Male

catkin

Female

catkin

Green

underneath

Ovary

hairless

Margin

toothed

Leafy

 branchlet

Young

female

floret

Summer Descriptions

Male

floret
76 Willows of Interior Alaska

Barren-ground Willow

Salix niphoclada Rydb

Salix brachycarpa Nutt. subsp. niphoclada (Rydb.) Argus

Identification

Summer: Low-to-medium-sized shrubs usually less than 1 m, but up to occasionally 3 m tall. Stems grayish black, not shiny, gray-hairy; leaves elongated

with a rounded tip, margin not toothed, upper side slightly hairy, underside

whitish, more hairy than upper side; petiole short (1-3 mm) yellow or reddish;

stipules minute or leaflike; catkins persisting; ovaries barrel-shaped, densely

hairy, short with 4 long dark stigmas on a short style.

Winter: see p. 29

Similar species:

Resembles S. glauca, which mostly grows at a higher elevation and has oval

pointed leaves, longer styles, and longer petioles (2.5-15 mm).

Phenology

Catkins and leaves start to develop from the end of May to mid-June; catkins

mature from mid-June.

Habitat

Willow thickets along rivers, recently disturbed sites, and alpine thickets. Salix

niphoclada is abundant in the early successional stages on the Tanana River.

Wetland indicator status

Facultative.

Insects

Micrurapteryx salicifoliella, Orgyia antiqua, Pontania sp. Rabdophaga rigidae,

and R. rosaria.
 77

Catkins

develop late

Male

catkin

Female

catkin

Pale

underneath

Ovary

densely

hairy Male

catkin

Margin not

toothed

Stem

densely

hairy

Stipule

minute

leafy

branchlet

Long

stigmas

Nectaries

longer than

stipe

Petiole

short

Style

short

Summer Descriptions

Male

floret
78 Willows of Interior Alaska

Skeleton-leaf Willow

Salix phlebophylla Andersson.

Identification

Dwarf shrub 1-7 cm tall. Stem stout, resting on the ground and rooting, forming

mats up to 2 m in diameter; leaves green beneath, margin hairy, leaves

persisting for several years, disintegrating except for the skeleton of leaf veins;

catkins robust, ovaries pear-shaped, usually hairy; nectaries shorter or equal

to the stipe.

Similar species

The skeletonized old leaves, dense mats, many-flowered female catkins and

hairy ovaries distinguish S. phlebophylla from other dwarf willows. Separated

from S. polaris by nectaries shorter than stipes and hairy leaf margins.

Habitat

Alpine tundra, Dryas-lichen tundra.

Insects

Pontania sp.
 79

Green

underneath

Margin

untoothed,

hairy

 Skeletonized

dried leaf

Upper side

very glossy

Base

pointed

Female catkins

densely flowered,

elongated

Ovary

usually hairy

Nectary

shorter than

stipe

Summer Descriptions
80 Willows of Interior Alaska

Polar Willow

Salix polaris Wahl.

Identification

Dwarf shrub 1-9 cm tall. Stems partly buried, rooting, branches coated with a

waxy whitish layer; leaves oval, not hairy at the margin, tip rounded, shiny

above, underside green glossy, veins raised; no stipules; ovaries hairy, style

long.

Similar species

Differs from other dwarf willows by leaves green underneath, hairy ovaries, and

long styles.

Phenology

Catkins develop at the same time as leaves.

Habitat

Alpine tundra, late snowbeds, alpine scree slopes.

Wetland indicator status

Facultative Wetland.

Uses: Salix polaris is the main source of forage for reindeer in Svalbard in

Norway (Skarpe and Van der Val 2002).
 81

Female

catkin

Green

underneath

Whitish

coating

Margin

untoothed

and hairless

No persistent

leaves

Ovary

hairy

Nectary

longer than

stipe

Style

long

Summer Descriptions

Male

floret
82 Willows of Interior Alaska

Park Willow

Salix pseudomonticola C. R. Ball.

Salix monticola Bebb sensu Argus 1973

Identification

Shrub 1-4 m tall. Young leaves reddish, mature leaves pale underneath, base

rounded, tip pointed, margin finely toothed; petiole and midvein reddish;

stipules rounded; catkins appear before the leaves, borne directly on the stem,

ovaries hairless; stipe 0.5-3 mm.

Winter: see p. 30.

Similar species:

Distinguished from S. myrtillifolia and S. pseudomyrsinites by the green

underside of the leaves. Resembles S. barclayi from which it is distinguished by

the catkins appearing before the leaves and attached directly to the main stem,

the young leaves and petiole reddish. Salix barclayi catkins are borne on leafy

branchlets and develop at the same time as the leaves. Distinguished from S.

richardsonii by the lack of persisting stipules.

Phenology

Catkins develop early in the spring; leaves appear later.

Habitat

Willow-sedge wetlands in white spruce forests. Sparse in early successional

stages on the Tanana River.

Wetland indicator status

Facultative Wetland.

Uses

“Diamond willows” are sometimes formed on this species.

Insects

Micrurapteryx salicifoliella, and Rabdophaga salicis.
 83

Catkins

develop

before the

leaves

Male

catkin

Female

catkin

Pale

underneath

Base

rounded

Petiole and

midvein reddish

Margin

toothed

Tip

pointed

Straight

hairs

no leafy

branchlet

Ovary

hairless

Short

stipe

Stipule

rounded

Summer Descriptions

Male

floret
84 Willows of Interior Alaska

Tall blueberry Willow

Salix pseudomyrsinites Andersson

S. myrtillifolia var. pseudomyrsinites (Andersson) Ball

S. myrtillifolia var. cordata (Andersson) Dorn

S. novae-angliae Andersson

Identification

Shrub 1-4 m tall. Young leaves reddish, hairless, or hairy with white or rust

colored hair, especially on the midvein, mature leaves green underneath, upper side hairy on the midvein; catkins on well-developed leafy branchlets;

ovaries hairless.

Similar species

Resembles S. myrtillifolia, which is smaller, has hairless leaves, and grows in

fens and bogs.

Phenology

Catkins develop at same time as leaves.

Habitat

Lakeshores, wetlands. Salix pseudomyrsinites is very common in early

succesional stages on the Tanana River.

Insects

Micrurapteryx salicifoliella, and Rabdophaga rosaria.
 85

Catkins develop

with the leaves

Female

catkin

Green

underneath

Branchlets

hairy

Margin

untoothed or

finely toothed Stipules minute

or leaf-like

White or

rusty hairs

Ovary

hairless

Nectary

shorter

than stipe

Summer Descriptions

Male

floret
86 Willows of Interior Alaska

Diamond-leaf Willow

Salix pulchra Cham.

Salix planifolia subsp. pulchra (Cham.) Argus var. pulchra

Identification

Summer: Low to tall shrub, 1-4 m. Stems glossy; leaves diamond-shaped, tip

pointed, margin not toothed, hairless, except on the upperside main vein, shiny

green above, whitish beneath; elongated stipules remain on the stem for

several years; catkins borne directly on the stem; ovaries hairy. Salix pulchra

variety yukonensis is characterized by densely hairy stems.

Winter: see p. 31. Stems shiny, tip of catkin winter bud sharp-pointed, stipules

linear, persistent on the stems, few orange-brown leaves often remaining on the

shrubs over winter. When present, the rosette gall with scales pointed at the tips

and long straight white hairs spreading from the center are diagnostic.

Similar species.

Salix pulchra is differentiated from other shrubby willows by hairless leaves

green above and whitish beneath, persistent linear stipules, catkins developing

before the leaves, and hairy ovaries.

Phenology

In the forest zone, the catkins start to develop as early as the end of February and

start releasing seeds by mid-June to early July. Leaves develop later from the end

of May to mid-July. In the alpine zone, depending on the snow conditions, the

catkins may only start maturing in mid-June or later with leaf development

delayed even later.

Habitat

Salix pulchra forms more or less dense thickets with other willows in wetlands

bordering lakes and rivers and in moist sites above treeline. It remains a low

shrub in fens and bogs, often associated with S. barclayi in the south, occupying

the wetter zone of the habitat. From sea level to high alpine tundra.

Wetland indicator status

Facultative Wetland.

Uses

This species is recommended for

revegetation projects using the dormant

cuttings method. It is also the main

source of food for ptarmigan, arctic hare,

musk oxen, caribou, reindeer, moose, and

beaver.

Insects, mites and diseases

Chrysomelidae, Dorytomus sp., Euura

sp., Pontania sp., Rabdophaga rigidae,

R. rosaria, R. strobiloides, Trypophloeus

striatulus, Eriophyiidae, and tar spot.
 87

Catkins

develop before

the leaves

Male

catkin

Female

catkin

Pale underneath

Ovary

hairy

Young

female

floret

Margin

untoothed

Persisting

stipule

Stem

glossy

Hairless

Shiny green

above

Catkin

borne on

the stem

Elongated

stipule

Diamond

shaped

Summer Descriptions

Male

floret
88 Willows of Interior Alaska

Net-vein Willow

Salix reticulata L.

Identification

Dwarf shrub 1-15 cm tall. Leaves deeply impressed, on long petiole; stipules

mostly lacking; catkins on terminal branchlets, appearing late in the summer;

2 nectaries, one on either side of the base of the pistil or stamens, the exposed

nectaries often forked as illustrated.

Similar species

The roundish deeply-veined leaves with long petioles are unique among our

local willows. In the absence of catkins, they could only be confused with the

alpine bearberry Arctostaphylos alpina, which is found in similar habitat. Salix

reticulata has one scale covering the winter buds, while Arctostaphylos alpina,

has several.

Phenology

Catkins and leaves develop late in mid-June.

Habitat

Salix reticulata does not tolerate shade and will grow in fens, where all plants

remain short, and in the alpine tundra where it is fairly common.

Wetland indicator status

Facultative.

Uses:

Browsed by Dall sheep (Ovis dalli dalli).

Insects and mites

Orgya antiqua, Pontania sp., Eriophyiidae, and rust fungus.
 89

Male

catkin

Female

catkin on

terminal

branchlet

Pale underneath

Ovary

hairy

Long petiole

Deeply

impressed

veins

Roundish

leaf

2 nectaries,

1 forked,

1 unforked (not

shown)

2 nectaries,

1 forked,

1 unforked (not

shown)

Summer Descriptions

Male

floret
90 Willows of Interior Alaska

Richardson’s Willow

Salix richardsonii Hook.

Salix lanata L. subsp. Richardsonii (Hook) A. Skv.

Identification

Summer: Low-to-medium shrub 0.5-2 m. Leaves hairy and shiny above, whitish

and hairless underneath; stipules large leaflike, persisting dried on the stem;

catkins borne directly on the stem; pear-shaped ovaries hairless. Pontaniainduced bean-shaped gall densely white-yellowish woolly.

Winter: see p. 32.

Similar species

The best character for distinguishing S. richardsonii is the presence of large

persistent leaflike stipules. These dried stipules give S. richardsonii a distinctive

scraggly appearance. Only S. alaxensis and S. glauca also bear woolly Pontaniainduced bean-shaped galls, but leaves of both species have hairs on the underside.

Phenology

Catkins develop before leaves.

Habitat

Subalpine and subarctic creek drainage, extensive willow thickets in moist sites.

Wetland indicator status

Facultative.

Uses

Browsed by moose.

Insects, mites and diseases

Chrysomelidae, Pontania sp, Rabdophaga rigidae, R. rosaria, R. salicis,

Eriophyiidae, tar spot and rust fungi.
 91

Catkins

develop

before the

leaves

Female

catkin

Pale

underneath

Ovary

hairless

Large

persisting

stipules

Shiny

green

above

Densely

flowered, oval

Catkin borne

on the stem

Summer Descriptions
92 Willows of Interior Alaska

Least Willow

Salix rotundifolia Trautv.

Identification

Minute shrub 5 cm tall. Stems mostly imbedded in ground vegetation or forming

mats on rocky soil; dried reddish leaves remain on the stem, leaves with 3

distinct veins, both sides glossy green, hairless; catkins few-flowered.

Two subspecies in Alaska:

Salix rotundifolia subsp. rotundifolia is 1-5 cm tall, catkins 4-12 flowered;

leaves 5-15 mm long, roundish.

Salix rotundifolia subsp. dodgeana is very small: 0.5 - 2 cm tall, catkins 2-4

flowered; leaves 4-6 mm long, oval.

Similar species:

Salix rotundifolia is the smallest willow in Alaska. Distinguished from other

dwarf willows by hairless leaves, green glossy on both sides, and few-flowered

catkins.

Phenology

Salix rotundifolia catkins and leaves start to develop at the end of June or later,

depending on the local weather conditions.

Habitat

This diminutive willow grows mostly on exposed mountain ridges, associated

with other tenacious plants like Moss Campion (Silene acaulis), White Mountain-Avens (Dryas integrifolia), Crowberry (Empetrum nigrum), and lichens.

Insects

Pontania sp.
 93

Female

catkin

Green

underneath

3 veins

Few-flowered

Male

catkin

Persisting but not

skeletonized leaves

Ovary

hairless

Nectary

longer than

stipe

Summer Descriptions

Male

floret
94 Willows of Interior Alaska

Scouler’s Willow

Salix scouleriana Barratt ex Hook.

Identification

Summer: Tall shrub or tree to 20 m. Several trunks, up to 60 cm in diameter;

bark gray, smooth; branches often inserted at right angles to the stems;

crown leaves are fairly small, broader near the tip; leaves on suckers and fastgrowing stem large; young leaves covered with white straight hair that sheds on

mature leaves and reveal short flat white or reddish-brown hair on the underside; catkins short; capsules pointing outward to give the female catkin a spikey

appearance; ovary densely hairy.

Winter: see p. 33.

Similar species

In early spring, Salix scouleriana is first tree to develop catkins. Salix alaxensis

catkins also appear early in the spring, but the catkins are long and erect. By

summer, no catkins remain on S. scouleriana. The reddish hairs are not always

present on large sucker leaves. Salix bebbiana leaf underside hairs are white,

long and curly, whereas in S. sitchensis leaf underside hairs are white, short, and

stiff, all oriented toward the tip of the leaves. Salix bebbiana bark is rough and is

impressed by deep grooves as opposed to S. scouleriana smooth gray bark and

the veins are more impressed on the upperside leaves than those of S. scouleriana.

Phenology

The catkin buds start to swell in midwinter and the male and female catkins

open by the end of March and start releasing the seeds by early June. At low

elevation in the forest zone, the catkins develop early in the spring, often before

the snow melts. The short catkins appear early in the spring before any other

plants leaf out. Female catkins mature, release their seeds, and shed before the

leaves mature. The leaves start developing from mid-May to early June.

Habitat

Very common in the forested zone. Scouler’s willow colonizes disturbed and

burned habitat. Isolated trees survive

longer in mixed forest after other willow

species have been overtopped by slowgrowing birches and spruces. Very

common at the edge of the forest, along

roadways. Also called fire willow

because it recolonizes burned forest.

Wetland indicator status

Facultative.

Continued p. 101
 95

Catkins

develop

before the

leaves

Male

catkin

Female

catkin

Pale

underneath

Ovary

densely

hairy

Orange-brown hue

Margin entire

(canopy leaf)

Densely

flowered

Spiky

appearance

Catkin borne

on the stem

Summer Descriptions

Male

floret
96 Willows of Interior Alaska

Setchell’s Willow

Salix setchelliana C. R. Ball

Identification

Dwarf shrub up to 30 cm tall. Stem mostly unbranched. Branchlets, are at first

densely woolly; leaves thick, hairless, fleshy like those of “Jade plant;” the

dried leaves of the previous year pinkish-gray; female catkins showy; ovaries

large, dark red turning bright yellow at maturity.

Similar species

In interior Alaska, no other willow has fleshy leaves.

Phenology

Salix setchelliana catkins and leaves start to develop in mid-June and seeds start

to disperse by mid-July. Salix setchelliana spread mostly vegetatively by root

shoots.

Habitat

This willow favors mostly barren sandbars of glacier rivers where the seasonal

rush of snowmelt water prevents other shrubs from getting permanently established.

Wetland indicator status

Facultative.
 97

Catkins

develop with

the leaves

Male

catkin

Female

catkin

Fleshy

leaf

2 nectaries Densely

flowered

Ovary

hairless

Style

reduced

Summer Descriptions

Male

floret
98 Willows of Interior Alaska

Sitka Willow

Salix sitchensis Sanson ex Bong

Identification

Summer: Shrub or tree up to 6 m tall. Leaves broader toward the tip, margin

toothless and slightly rolled under, underside of leaves covered by short stiff

hairs oriented toward the tip, giving a silky shine, like the fur of a seal; catkins,

long and narrow, develop at the same time as the leaves; ovaries pear-shaped. In

southcentral Alaska, S. Sitchensis is the only willow with a single anther for

each male flower.

Winter: see p. 34.

Similar species

Salix scouleriana leaf underside, covered with short flat white or reddish hairs,

is not silky in appearance. Salix scouleriana does not bear catkins and mature

leaves simultaneously.

Phenology

Salix sitchensis catkins and leaves develop at the same time, from mid-May to

early July and start releasing seeds in mid-June at favorable sites.

Habitat

Very common in coastal locations where it forms dense thickets in wetlands;

disturbed sites, and on sandbars of fast-flowing creeks; south of the Alaska

Range.

Uses

This species is recommended for revegetation projects using the dormant

cuttings method. The flexible twigs are used by coastal Alaska Natives for

weaving baskets.

Insects and mites

Chrysomelidae, Dorytomus sp., Itomeyia sp., Pontania sp., Phyllocolpa sp.,

Rabdophaga rosaria, and Eriophyiidae.
 99

Catkins develop

with the leaves

Male

catkin

Female

catkin

Pale

underneath

Ovary

hairy

Single

anther

Broader

near tip

Long

catkin

Silky sheen

underneath

Margin not

toothed

Summer Descriptions

Male

floret
100 Willows of Interior Alaska

Salix alaxensis

Continued from p. 44

Uses

Felt-leaf willow leaves have a relatively low content of bitter anti-herbivory

substances compared to most other willows. Moose are very fond of Felt-leaf

willows and reach the higher branches by breaking off the small trunks. It is also

an important food source for snowshoe hare, beaver, and smaller herbivores.

Feltleaf Willow is the favorite species for riverbanks restoration because it

roots readily from cuttings.

The young leaves are edible and are traditionally collected and preserved by

Eskimos. The inner bark has a sweet taste and can be eaten raw or cooked. The

long leafless sprigs cut early in the spring make fine interior decorations of

“pussy willows” when the young catkins burst open.

“Diamond willows” are sometimes formed on this species.

Insects and mites

Chrysomelidae, Dorytomus sp., Euura sp., Itomeyia sp., Orgyia antiqua,

Pontania sp., Phyllocolpa sp., Rabdophaga rosaria, R. rigidae, R. strobiloides,

Saperda concolor, Trypophleus striatulus, and Eriophyiidae.

Salix barclayi

Continued from p. 54

Insects and diseases

Chrysomelidae, Dorytomus sp., Euura sp., Orgyia antiqua, Phyllocolpa sp.,

Pontania sp., Rabdophaga rigidae, R. rosaria, R. salicis, Trypophleus striatulus, Trichiosoma triangulum, Eriophyiidae, rust, white mildew, and tar spots.

Salix bebbiana

Continued from p. 58

Uses

Shrubs are usually heavily browsed by moose, causing them to be manybranched from ground level. Stiff erect Bebb shrubs remain accessible above

snow cover for moose after lower willow shrubs with flexible stems have been

buried under the snowpack. Where overwintering moose density is high, Bebb

willows are heavily browsed by the end of the winter, little remains of the last

summer’s new growth.

Winter cuttings do not root well and are not recommended for revegetation

projects.

Most “Diamond willows” sticks and poles harvested for crafts are of Salix

bebbiana.

Insects

Euura sp., Micrurapteryx salicifoliella, Orgyia antiqua, Pontania sp., Rabdophaga rigidae, R. rosaria, R. salicis, R. strobiloides, and rust spot.
Summer Descriptions 101

Salix scouleriana

Continued from p. 94

Uses

Moose are fond of the lush S. scouleriana suckers. Moose feed on foliage and

strip the bark in winter (Weixelman et al. 1998). Post-fire upland habitats,

recolonized by abundant fast-growing shoots of the “fire willow” S. scouleriana,

support the highest densities of moose in Alaska. Simulation of post-fire

conditions, to increase browse available to moose, has been experimentally done

by mechanical crushing and prescribed burns of mature forest.

The early catkins are a very important source of nectar for insects such as bees

and flies.

Winter cuttings do not root well and are not recommended for revegetation

projects.

“Diamond willows” are sometimes formed on this species.

Insects and diseases

Chrysomelidae, Euura sp., Itomeyia sp., Micrurapteryx salicifoliella, Orgyia

antiqua, Pontania sp., Rabdophaga rigidae, R. rosaria, R. salicis, and

Trichiosoma triangulum.
102 Willows of Interior Alaska

S. polaris S. phlebophylla

S. setchelliana

S. myrtillifolia

S. rotundifolia

S. arctica

S. reticulata

S. fuscescens

Female catkins of dwarf willows less than 20 cm tall

S. chamissonis

S. arctophila
 103

Pistils of dwarf willows less than 20 cm tall

S. arctica

S. fuscescens

S. myrtillifolia

S. phlebophylla S. polaris

S. reticulata

S. rotundifolia

S. setchelliana

S. arctophila

S. chamissonis

Comparison of Female Catkins and Pistils
104 Willows of Interior Alaska

S. pulchra

S. richardsonii S. pseudomonticola

S. arbusculoides

S. sitchensis

S. scouleriana S. alaxensis

Female catkins of willows taller than 20 cm whose catkins

develop before the leaves

Catkins are mostly borne directly on the stem.

S. barrattiana
 105

Pistils of willows taller than 20 cm whose catkins develop

before the leaves

S. alaxensis

S. arbusculoides S. richardsonii

S. scouleriana

S. sitchensis

S. pulchra

Comparison of Female Catkins and Pistils

S. pseudomonticola

S. barrattiana
106 Willows of Interior Alaska

Female catkins of willows taller than 20 cm whose catkins

develop at the same time as the leaves

S. barclayi

S. pseudomyrsinites

S. bebbiana

S. niphoclada

Catkins are borne on leafy branchlet

S. interior

S. myrtillifolia

S. sitchensis

S. glauca

S. hastata

S. candida

S. lasiandra

S. athabascensis
 107

S. bebbiana

S. glauca

S. myrtillifolia

S. niphoclada

S. sitchensis

S. pseudomyrsinites

S. hastata

Comparison of Female Catkins and Pistils

Pistils of willows taller than 20 cm whose catkins develop

at the same time as the leaves

S. interior

S. candida

S. athabascensis

S. lasiandra

S. barclayi
108 Willows of Interior Alaska

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University Press, Ames, Iowa.

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Nat. Sci. Publ. Bot. 2. 279 pp.

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Yukon Territory and Adjacent Regions. Workshop on willow identification.

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Collet, D. 2002 Willows of Southcentral Alaska. Kenai Watershed Forum. 109

pp.

Cremer, K. 1999. Willow Management for Australian Rivers. Australian Natural

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Densmore, R. A. and J. C. Zasada. 1983. Seed Dispersal and Dormancy Patterns

in Northern Willows: Ecological and Evolutionary Significance. Can. J.

Bot. 61: 3207-3216.

Densmore, R. V., M. E. Vander Meer, and N. G. Dunkle. 2000. Native Plant

Revegetation Manual for Denali National Park and Preserve. USGS

Biological Resources Division, Information and Technology Report, 2000-

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Bibliography
110 Willows of Interior Alaska

Useful information sources:

American Willow Grower Network. 412 County Road 31, Norwich NY 13815-

3149.

Directory of Alaska Native Plant Sources. Alaska Plant Material Center. HCO2

Box 7440, Palmer, Alaska 99645.

The 1996 National List of Vascular Plant Species that Occur in Wetlands can be

downloaded from this website: http://www.nwi.fws.gov/bha/

George Argus' s out-of-print 1973 The Genus Salix in Alaska and the Yukon is

available for download at http://info.dec.state.ak.us/ciimms/news.htm, the

website of the Information Management System of the State of Alaska.

George Argus’ s electronic copy of the Alaska and Yukon Willow Workbook and

the interactive Key to Salix (INTKEY) are available for download at http://

www.uaa.alaska.edu/enri/willow/index.html, the website of the Alaska Natural

Heritage Program.
 111

Glossary

Alluvions- See p. 6

Anther- See p. 11

Bloom- See p. 44

Bract- See p. 11

Bud scale- See p. 36

Catkin- See p. 11

Compensatory growth see p. 8

Fen- Wetland dominated by grasses and sedges.

Gall- Swelling or abnormality in plant tissue caused by an organism. See p. 13.

Genus- See p.12

Hybrid- Offspring of two separate species.

Floret- See p. 11

Midvein- See p. 11

Nectary- See p. 11

Ovary- See p. 11

Phenology- See p. 12

Petiole- See p. 11

Stamen- See p. 11

Stigma- See p. 11

Stipule- See p. 11

Sucker- See p. 18

Glossary