LATE QUATERNARY 

VEGETATION HI STORY 

OF THE 

YELLOWSTONE LAKE BASIN, 

WYOMING 

Late Quaternary 

Vegetation History of the 

Yellowstone Lake Basin, 

Wyoming 

By RICHARD G. BAKER 

GEOLOGY OF YELLOWSTONE NATIONAL PARK 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 729-E 

Analyses of poUen and plant macrofossils 

from sediment cores indicate complex 

changes in the vegetation succession 

from deglaciation about 19,000 years 

ago to the present 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1976 
UNITED STATES DEPARTMENT OF THE INTERIOR 

THOMAS S. KLEPPE, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress Cataloging in Publication Data 

Baker, Richard G. 

Late Quaternary vegetation history of the Yellowstone Lake Basin, Wyoming. 

(Geology of Yellowstone National Park) (Geological Survey Professional Paper 729-E) 

Bibliography: p. 

Includes index. 

Supt. of Docs. no.: I 19.16:729-E 

1. Paleobotany-Quaternary. 2. Paleobotany-Wyoming-Yellowstone Lake basin. 3. Palynology-Wyoming-Yellowstone Lake 

basin. 

I. Title. II. Series. III. Series: United States Geological Survey Professional Paper 729-E. 

QE931.B34 560'.178 75-619373 

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

Washington, D.C. 20402 

Stock Number 024-001-02860-3 
Yellowstone National Park, the oldest of the 

areas set aside as part of the national park system, lies amidst the Rocky Mountains in northwestern Wyoming and adjacent parts of Montana 

and Idaho. Embracing large, diverse, and complex 

geologic features, the park is in an area that is 

critical to the interpretation of many significant 

regional geologic problems. In order to provide 

basic data bearing on these problems, the U.S. 

Geological Survey in 1965 initiated a broad program of comprehensive geologic and geophysical 

investigations within the park. This program was 

carried out with the cooperation of the National 

Park Service, and ~as also aided by the National 

Aeronautics and Space Administration, which 

supported the gathering of geologic information 

needed in testing and in interpreting results from 

various remote sensing devices. This professional 

paper chapter is one of a series of technical geologic reports resulting from these investigations. 

CONTENTS 

Page 

Metric-English equivalents............................... VI 

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E1 

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Location and climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

Methods of study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

Glacial history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

Vegetation of Yellowstone National Park and surrounding area 7 

Regional vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Artemisia steppe association . . . . . . . . . . . . . . . . . . . . . . 10 

Pseudotsuga association . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Pinus contorta forest association . . . . . . . . . . . . . . . . . . 12 

Picea-Abies-Pinus albicaulis forest association . . . . . . 12 

Alpine association . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Local vegetation around the coring sites . . . . . . . . . . . . . . . . 13 

Nuphar-Potamogeton type . . . . . . . . . . . . . . . . . . . . . . . 114 

Menyanthes trifoliata type . . . . . . . . . . . . . . . . . . . . . . . 14 

Carex utriculata type . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

Carex diandra-PotentiUa palustris type . . . . . . . . . . . . 14 

Calamagrostis-Salix-Sedum rhodanthum type. . . . . . . 15 

Other paleobotanical work in the area . . . . . . . . . . . . . . . . . . 15 

Pollen surface samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

Surface samples from the Artemisia steppe............. 16 

Surface sample from Pseudotsuga association . . . . . . . . . . . 18 

Surface samples in Pinus contorta forests . . . . . . . . . . . . . . . 18 

Surface samples from Picea-Abies-Pt"nus albicaulis 

forests........................................... 18 

Surface samples from Picea-Abies-Pinus albicaulis 

parklands and tundra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

Pollen ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Quaternary palynology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Materials and procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Pollen and seed identification . . . . . . . . . . . . . . . . . . . . . . . . . 24 

Selaginellaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 

Pinaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 

Betulaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

Page 

Quatenary palynology-Continued 

Pollen and seed identification-Continued 

Compositae ..................................... E28 

Crassulaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Cruciferae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Haloragaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Loranthaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Menyanthaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Nymphaeaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Onagraceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Polemoniaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Polygonaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Ranunculaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

Rosaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

Sa.J.icaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

Saxifragaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

Cyperaceae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

Gramineae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Naiadaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Typhaceae ..................................... 30 

Other types of fossils . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Algae .......................................... 30 

Description of pollen zones . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Picea-Juniperus-Pinus albicaulis zone 

(960 -770 em) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Betula subzone (960- 875 em) . . . . . . . . . . . . . . . . . 31 

Populus subzone (875 -770 em) . . . . . . . . . . . . . . . 35 

Pinus contorta zone (770 - 0 em) . . . . . . . . . . . . . . . . . . . 36 

Pinus contorta-Pinus albicaulis subzone 

(770- 600 em). .. .. .. .. .. .. .. .. .. .. .. .. .. . . 37 

Pinus contorta subzone (600 -420 em).......... 37 

Picea-Abies-Pinus contQTta subzone 

(420-0cm) ............................... 38 

Discussion and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 

References cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 

Index .................................................. 45 

ILLUSTRATIONS 

[Plates follow index) 

PLATE 1-4. Photomicrographs of fossil pollen grains from Buckbean fen. 

5 -10. Photomicrographs of plant macrofossils and modern seeds and fruits. 

Page 

FIGURE 1. Photograph of Southeast Arm of Yellowstone Lake showing coring area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . E2 

2. Charts summarizing climatic data for Yellowstone National Park . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

3. Photograph showing shorelines above Southeast Arm of Yellowstone Lake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

4. Schematic cross section showing relationship between Two Ocean Plateau, the filled lagoons, the lake levels, and the 

coring sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

5. Sketch maps showing geomorphic development of coring area as glacier ice melted and lake level fell . . . . . . . . . . . . . . . . 6 

6. Vegetation map of the southeast corner of Yellowstone National Park showing highestlake level . . . . . . . . . . . . . . . . . . . 11 

v 
VI CONTENTS 

Page 

FIGURE 7 o Map of local vegetation around coring site, showing surface sample and core localities at Buckbean fen and Lilypad 

pond ................................................................ : . ............................. E13 

8- 110 Photographs: 

8o Coring site at Buckbean fen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

9o Closeup of small pond shown in figure 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

100 Carex utricu'Ulta type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

11o Carex diandra-Potenti/J4 palustris type .. .. .. .. .. .. .. .. .. .. .. .... . .. .. .. .. .. .. .. . . . . .. .. .. .. .. . . .. .. .. 15 

120 Map of Yellowstone National Park, showing localities of surface samples and coring areas. . . . . . . . . . . . . . . . . . . . . . . . . . 16 

13o Diagram showing pollen from surface samples arranged by elevations and by vegetation types . . . . . . . . . . . . . . . . . . . . . 18 

14o Diagram showing ratios for surface pollen samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

15o Diagram of pollen from Buckbean fen core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

160 Diagrammatic sketch showing relationships between zones, carbon-14 and extrapolated ages, and time stratigraphic 

boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 

17 o Diagram of plant macrofossils from Buckbean fen core. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

18o Diagram of plant macrofossils from lower 2 metres of.Lilypad pond core. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

19o Diagram showing ratios for fossil pollen from Buckbean fen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

TABLES 

Page 

TABLE 1. Scientific names, and common names ii available, of plant taxa mentioned in text, tables, and illustrations . . . . . . . . . . E7 

2o Locality .and description of surface samples and collection stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

3o Summary ofinferred changes in environment at Buckbean fen during the last 12,000+ years. . . . . . . . . . . . . . . . . . . . . . 25 

4o Pollen counts for Buckbean fen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 

5o Lithologic description of Buckbean fen and basal section of Lilypad pond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

6o Tentative correlation of pollen sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 

METRIC-ENGLISH EQUIVALENTS 

Metric unit 

millimetre (mm) metre (m) 

kilometre ( km) 

square metre (m2) 

square kilometre (km2) 

hectare (ha) 

cubic centimetre (cm3 ) 

litre (1) 

cubic metre (mS) 

cubic metre cubic hectometre (hm3) 

litre 

litre 

litre 

cubic metre 

cubic metre 

gram (g) 

gram 

tonne (t) tonne 

English equivalent 

Length 

0.03937 inch (in) 

3.28 feet (ft) 

.62 mile (mi) 

Area 

10.76 

.386 

2.47 

Volume 

square feet (ft2) 

square mile (mi2) acres 

0.061 cubic inch (ina) 

61.03 cubic inches 

35.31 cubic feet (ft3 ) 

.00081 acre-foot (acre-ft) 

=810.7 acre-feet 

2.113 pints (pt) 1.06 quarts (qt) .26 gallon (gal) .00026 million gallons (Mgal or 10a gal) 6.290 barrels (bbl) (1 bbl=42 gal) 

Weight 

O.O:l5 ounce, avoirdupois (oz avdp) .0022 pound, avoirdupois (lb avdp) 1.1 tons, short (2,000 lb) .98 ton, long (2,240 lb) 

Specific combinations 

kilogram per square centimetre (kg/cm2) kilogram per square 

centimetre 

cubic metre per second 

(ms/s) 

0.96 

.98 

35.3 

atmosphere (atm) 

bar (0.9869 atm) 

cubic feet per second (fts;s) 

Metric unit English equivalent 

Specific combinations--Continued 

litre per second (1/s) 

cubic metre per second 

per square kilometre 

[(ma;s)/km2) 

metre per day (m/d) 

metre per kilometre 

(m/km) 

kilometre per hour 

(km/h) metre per second (m/s) metre squared per day (m2jd) 

cubic metre per second 

(ms;s) 

cubic metre per minute 

(m3/min) 

litre per second (1/s) litre per second per metre [(1/s)/m] 

kilometre per hour 

(km/h) metre per second (m/s) 

gram per cubic 

centimetre (g/cm3) 

gram per square centimetre (g/cm2) 

gram per square 

centimetre 

degree Celsius (°C) 

degrees Celsius 

(temperature) 

.0353 cubic foot per second 

91.47 cubic feet per second per 

= 3.28 

square mile [ (fts;s) /mi2) 

feet per day (hydraulic conductivity) (ft/d) 

5.28 feet per mtle (ft/mi) 

.9113 foot per second (ft/s) 3.28 feet per second 

10.764 feet squared per day (ft2jd) (transmissivity) 

22.826 million gallons per day (Mgal/d) 

=264.2 gallons per minute (gal/min) 

15.85 gallons per minute 

4.83 gallons per minute per foot 

[(gal/min) /ft] 

.62 mtle per hour (mi/h) 2.237 miles per hour 

62.4:-l pounds per cubic foot (lb/ft3) 

2.048 pounds per square foot (lb/ft2 ) 

.0142 pound per square inch (lb/inll) 

Temperature 

= 1.8 degrees Fahrenheit (°F) 

= [ (1.8 X •c) + 32] degrees Fahrenheit 
GEOLOGY OF YELLOWSTONE NATIONAL PARK 

LATE QUATERNARY VEGETATION HISTORY OF THE 

YELLOWSTONE LAKE BASIN, WYOl\fiNG 

By RICHARD G. BAKER 

ABSTRACT 

A large icecap flowed radially from the Yellowstone Lake basin 

during Pinedale Hate Pleistocene) time. As it melted, kettles, 

ice-marginal lakes, and associated ice-contact deposits formed 

between the glacier and the basin sides. With further wasting, lake 

levels dropped, beaches formed at progressively lower elevations, 

and "lagoons occupied the kettles. A core from Buckbean fen, an 

abandoned lagoon 15 feet above modern lake level, was analyzed 

for pollen and seeds. Macrofossils from the base of lagoon 

sediments in Lilypad pond 40 feet above the lake were also 

examined. 

Surface pollen samples were collected to relate modern pollen 

rain to vegetation distribution and to aid in the interpretation of 

fossil pollen spectra. Steppe, Pinus contorta forests, and PiceaAbies-Pinus albicaulis forests can be recognized from their pollen 

rain. Pollen rain in alpine tundra is similar to that in subalpine 

parklands, but both are distinct from pollen rain in other 

vegetation associations. Few data are available from Pseudotsuga 

forests. 

The Buckbean fen core has two pollen zones-a lower zone and 

an upper zone. The lower zone (960-770 em) is characterized by 

more than 50 percent nonarboreal pollen with maxima of Picea, 

Abies, Pinus albicaulis, Betula, Juniperus, Populus, Gramineeae, 

and Compositae. It has two subzones-the Betula and the Populus. 

The Betula subzone (960-875 em) has a Betula pollen maximum, 

Betula gla:ndulosa seeds, a few alpine macrofossils, and very rare 

arboreal macrofossils. This fossil assemblage suggests that the site 

was about at treeline for some time after the glacier melted and 

that treeline was about 2,000 feet lower than at present in this part 

of Yellowstone National Park. The assemblage suggests that the 

climate was cold and moist. The sediments of the subzone contain 

too little organic matter for radiocarbon dating, but the base of the 

subzone is estimated to be about 14,500 years old. 

The Populus subzone (875 -770 em) contains a Populus maximum 

and common arboreal macrofossils. Betula pollen decreases, but 

other pollen types remain at nearly constant levels. This subzone 

marks the invasion of forest in the area and suggests a slightly 

warmer climate. The top of the Picea-Abies-Pinus albicaulis zone is 

radiocarbon dated at 11,630± 180 years B.P. oefore present). 

The upper pollen, or Pinus contorta, zone (770- 0 em) is 

characterized by Pinus contorta pollen and needles and by 60-85 

percent total Pt'nus pollen. Three subzones are defined, as follows. 

A Pinus contorta-Pt'nus albicaulis subzone (770- 600 em) is 

characterized by pollen and needles of both Pinus albicaulis and 

Pinus contorta. The two pines apparently grew together locally in 

the absence ofPicea and Abies, which suggests a cool, dry climate. 

This subzone was deposited from about 11,630 to about 10,160 

years B.P. 

A Pinus contorta subzone (600 -420 em) contains high values of 

pine pollen, mainly lodgepole, and low values of Pinus albicaulis, 

Picea, and Abies. This subzone includes the Altithermal period, 

and represents a warmer, drier climate from about 10,160 to about 

5,000 years B.P., but a hiatus representing as much as 4,000 years 

is probably present in this interval. 

APicea-Abies-Pinus contorta subzone (420 -0 em), representing 

about the last 5,000 years, shows a recurrence of Picea and Abies 

pollen and needles. This is the Neoglacial period, and the pollen 

suggest a climate that is cooler and moister than during deposition l of the preceding subzone. 

INTRODUCTION 

The primary purpose of this study was to deduce 

the vegetation history during the last 13,000 years of 

the Yellowstone Lake region. Secondary purposes 

were (1) to infer general climatic changes during this 

period, and (2) to provide a standard sequence of 

dated climatic and vegetation changes for correlation 

with glacial fluctuations. 

The fieldwork was carried out in 1966 and 1967 

under the supervision of G. M. Richmond, as part of 

the glacial geology project, Yellowstone National Park 

study, conducted by the U.S. Geological Survey in eooperation with the National Aeronautics and Space 

Administration and the National Park Service. 

LOCATION AND CLIMATE 

Materials for this study were collected from Yellowstone National Park, northwest Wyoming. Much of 

the park is a plateau (referred to informally in this 

report as the Yellowstone plateau) that is 

8,000- 9,000 feet above sea level. The Absaroka 

Range on the eastern margin of the park exceeds 

11,000 feet, and isolated peaks in the park exceed 

10,000 feet. Fossil pollen samples were collected from 

depressions near the tip of the Southeast Arm of 

El 
E2 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

Yellowstone Lake (figs. 1 and 12). The elevation of the 

coring area is about 7,800 feet, and local relief is as 

much as 1,500 feet. 

The climate of Yellowstone National Park has been 

summarized by Fletcher (1927a and b) and Lowery 

([undated] and 1960). Data from 30-year records for 

Mammoth (elev 6,241 ft) and Yellowstone Lake (Lake 

Ranger Station, elev 7, 762 ft) are compared with 

predicted climatic curves (Baker, 1944) in figure 2. 

Shorter unpublished records from 10 ranger stations 

are also available from the National Park Service. No 

climatic recording stations are located in the southeast 

corner of the park near the coring sites, but 

generalized maps are available (Lowery, 1960). 

Mean annual temperature at Mammoth is 38.9°F, 

and at Yellowstone Lake it is 32.8°F. In summer, the 

cold water of Yellowstone Lake depresses daytime 

temperatures along its shoreline (Lowery [undated]), 

and mean annual temperatures are lower by a few 

degrees near the lake than elsewhere (Fletcher, 

1927 a). Mean minimum temperatures for July and 

January are a few degrees cooler in the Southeast 

Arm of Yell ow stone Lake than at the Lake Ranger 

Station (Lowery, 1960). 

The average annual precipitation recorded in the 

park increases from less than 14 inches at Lamar 

Ranger Station in the northeast to 38 inches at Bechler 

River Ranger Station in the southwest (National Park 

Service, unpub. data). The coring area receives about 

32 inches per year (Lowery, 1960). Unlike any other 

area in the Rocky Mountain region, Yellowstone 

National Park has precipitation rather evenly 

distributed throughout the year (Baker, 1944). At 

RED MTS 

FIGURE !.-Southeast Arm of Yellowstone Lake, viewed to the 

west from Absaroka Range showing coring area. D, Yellowstone 

River delta; TO, Two Ocean Plateau. Arrow indicates coring 

area; X, surface sample locality SS -38. Lake in foreground is 

dammed by a moraine of late Pinedale age. 

Mammoth and Yellowstone Lake, precipitation 

averages about 1 - 2 inches every month. 

Snowfall ranges in amount from less than 100 inches 

at lower elevations to well over 200 inches (locally 

about 400 inches) at higher elevations (Lowery 

[undated]). Snowfall in the coring area is probably 

close to 200 inches per year (Fletcher, 1927 a). 

Summers in the park tend to be sunny, with 65 - 75 

percent sunshine, and winters more cloudy, with an 

average of 40 percent sunshine (Lowery [undated]). 

Prevailing wind directions at Mammoth are southwesterly throughout the year (Fletcher, 1927a). No 

wind records are available from around the lake. 

ACKNOWLEDGMENTS 

John Good, former Chief Naturalist, Yellowstone 

National Park, granted permission to use an 

unpublished map of the vegetation of the park as 

source material for the map published herein. Robert 

Morey and W. F. White, National Park Service, 

extended many courtesies while I was in the field. 

William Hendrickson, Research Biologist, National 

Park Service, provided advice and information on the 

climate and vegetation of the park. W. A. Weber, 

University of Colorado, identified plants and 

cooperated in the assembly of the seed collection of the 

University of Colorado Herbarium. This paper 

is the outgrowth of a Ph. D. dissertation, and W.C. 

Bradley and P. W. Birkeland, University of Colorado, 

and Robert Tschudy, U.S. Geological Survey, offered 

many helpful suggestions during the preparation of 

the manuscript . Special thanks are extended to E.B. 

Leopold, for making available the facilities of the 

palynology laboratory of the U.S. Geological Survey, 

to Meyer Rubin, for radiocarbon dating a number of 

samples from critical levels in the cores, and to W.C. 

Bradley, who served as my dissertation advisor. The 

final year of support came from National Science 

Foundation grant B- 81590 to E. B. Leopold. 

METHODS OF STUDY 

For the purpose of this study, cores for pollen and 

plant-macrofossil analysis were taken from four 

abandoned lagoons of Yellowstone Lake. During and 

after the melting of the last Pleistocene icecap in the 

Yellowstone Lake basin, the successively lower lake 

levels left a series of shorelines between 220 feet and 

the present lake level (Richmond, 1969c) (figs. 3 and 

4). Open lagoons associated with the old shorelines 

were abandoned as the lake fell and were left as 

isolated, shallow ponds. The ponds gradually filled 

with sediment and are now covered with semiaquatic 

vegetation. Cores were taken from lagoons at eleva-
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E3 

12,000 

1- 10,000 UJ 

UJ 

lL 

~ 8000 

z· 

Q 

1- 6000 < 

> 

UJ 

....J 

UJ 4000 

~ 10,000 UJ 

lL 

~ 

z 

0 

1-

< 

> 

UJ 

....J 

UJ 

8000 

6000 

4000 

~ 10,000 UJ 

lL 

~ 8000 

z 

0 

~ 6000 

> 

w 

....J 

UJ 4000 

120 

JULY TEMPERATURE, IN DEGREES F. 

JANUARY TEMPERATURE, IN DEGREES F. 

LENGTH OF GROWING SEASON, IN DAYS 

15 

~ 10 UJ 

u 

a: 

~ 5 

• 

• 

• • • 

II OJ FMAM J J AS OND 

MONTHLY PRECIPITATION 

~ 10,000 r---r---.------.---...----, 

UJ 

lL 

~ 

z' 

0 

1-

< 

> 

UJ 

....J 

UJ 

1-

UJ 

UJ 

lL 

~ 

z 

Q 

1-

< 

> 

UJ 

....J 

UJ 

8000 

6000 

10,000 

8000 

6000 

40000 

PRECIPITATION, IN INCHES 

50 100 150 200 250 

SNOWFALL, IN INCHES 

FiGURE 2.-Summary of climatic data (dots) for Yellowstone National Park compared with predicted climatic curves (lines). Dots at 6,241-

foot elevation are data for Mammoth; dots at 7,762-foot elevation are data for Yellowstone Lake (Lake Ranger Station). (From F. S. 

Baker, 1944; data from Becker and Alyea, 1964a and b, Lowery, [undated] and 1960.) 

tions of 90, 40, 25, and 15 feet above modern lake 

level. The core from the 15-foot lagoon (here 

informally called Buckbean fen) contained the most 

complete sequence and was selected for detailed 

pollen and seed analysis. Macrofossils from the basal2 

m of the 40-foot lagoon (here informally called Lilypad 

pond) are shown in a separate diagram and correlated 

with the bottom 2 m of the Buckbean fen core. 

The pollen assemblages represent mainly upland 

plants whose pollen was produced in large quantities, 

was efficiently dispersed, and was well preserved. 

Analysis provided information on regional vegetation 

patterns down to the level of families or selected 

genera. Species and even some genera cannot be 

est;tblished from pollen alone. Some of the pollen 

types apparently blew in from considerable distances. 

Study of plant macrofossils (seeds, fruits, bracts, 

leaves, flowers, twigs, and cone scales) provided 

information on local vegetation, usually to the level of 

species. The pollen and macrofossil data that show 

changes in vegetation through time are plotted in 

figures 15 and 17. Radiocarbon dates on organic 

material from the core, which show the ages at four 

levels in the core, are also plotted in figures 15 and 17. 

Studies of modern vegetation and pollen rain in 

Yellowstone N a tiona! Park were important aids in 

interpreting past vegetation. Modern vegetation 

associations, with increasing elevation, are Artemisia 
E4 GEOLOGY OF YELLOWSTONE ~~ONAL PARK 

FIGURE 3.-Shorelines above Southeast Arm of Yellowstone Lake. 

Lower benches are 110, 90, 60, and 25 feet above the lake; higher 

benches are kame terraces or rock surfaces. View is to the 

northeast. 

steppe, Pseudotsuga forest, Pinus contorta forest, 

Picea-Abies-Pinus albicaulis forest, and alpine tundra. 

A generalized vegetation map of the southeast corner 

of Yellowstone National Park (fig. 6) was made from 

field observations, topographic maps, and an 

unpublished vegetation map by the National Park 

Service. In addition, a reconnaissance map was made 

of local vegetation types around the coring sites (fig. 

7). 

The coring sites are located near the boundary 

between two vegetation types (fig. 7). Pinus contorta 

forests occupy lower, drier areas, and PiceaAbies-Pinus albicaulis forests extend up northfacing slopes to the Two Ocean Plateau (fig. 7). 

Past climatic fluctuations caused this boundary to 

8200 

8100 

f-

~ 8000 

u. 

6 7900 

f-

< 

> 

w 

_.J 7800 w 

SOUTH 

- Two Ocean Pla tea u 

(e lev 9200 ft) 

Kame terrace 

\ 

\ 

\ 

Trail 

Creek 

pond 

~ 

migrate across the coring sites, and these migrations 

are recorded in the pollen macrofossil sequences. 

Modern pollen was analyzed from surface sediments 

in ponds situated in the major vegetation 

associations and the data were plotted (fig. 13). Pollen 

rain from most associations is sufficiently distinctive to allow its recognition in fossil pollen 

assemblages. Some fossil assemblages do not match 

any modern samples, however, and these may 

represent ancient vegetation associations not now 

present in the Yellowstone National Park area. 

Elevational limits of modern vegetation associations are controlled by climate, but precise 

relationships are still poorly known. Where the 

distributional limits of certain plant taxa are found to 

coincide with a specific mean temperature, past distributional limits of those taxa may suggest 

paleotemperatures (Wolfe and Leopold, 1967). This 

approach must be used with caution because the 

coincidence may not be simply a cause-and-effect 

relationship. In this study only broad climatic changes 

can be inferred from most of the past vegetation 

changes. 

Glacial deposits and topographic features of late 

Quaternary age in Yellowstone National Park have 

been mapped by G. M. Richmond, K. L. Pierce, and 

H. A. Waldrop (U.S. Geological Survey, 1972). 

Radiocarbon dates suggest that the Pinedale 

Glaciation began after 27,000 ±800 years ag·o in 

nearby Jackson Hole, Wyo. (Levin and others, 1965). 

Pinedale glaciers had retreated extensively by about 

13,000 years ago in Yellowstone National Park 

25-foot 

lagoon 

NORTH 

SOUTHEAST A R M 

YELL OWSTONE 

LA KE 

7700 

___ T ___ _ 

Present lake level Core - Core Core (ele v 77 33 ft) de pth 32.8 feet 

7600 ~----------------------- ------------------~ 

r------------------About 1 mile -------- ------------;-.j 

FIGURE 4.-Schematic cross section showing relationship between Two Ocean Plateau, the filled lagoons, the lake levels, and the coring 

sites. See figure 7 for location of ponds. 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E5 

(Richmond, 1970b; Bender and others, 1971). 

Dates on glacial advances elsewhere in the western 

cordillera (Richmond, 1965, 1970b; Porter and 

Denton, 1967) correlate well with cool, moist periods 

inferred from my paleobotanical record and support 

geomorphic and soil-stratigraphic correlation of the 

Yellowstone glacial deposits with the standard Rocky 

Mountain glacial sequence (Richmond, 1965). 

Our knowledge of late Quaternary regional climatic 

changes is still sketchy. This study provides new data 

in an area heretofore unstudied. More data of this sort 

will contribute answers to questions such as the 

following: How synchronous were regional climatic 

changes? Were climatic changes similar in nature from 

one region to another? 

GLACIAL HISTORY 

Yellowstone National Park was glaciated several 

times during early and mid-Quaternary time 

(Richmond, 1969c, 1970a). Glacial till underlies an 

ash-flow tuff about 600,000 years old near Tower 

Falls (U.S. Geological Survey, 1972) and midQuaternary sections containing glacial deposits are 

known from scattered sections elsewhere in the park. 

The Bull Lake Glaciation is the oldest glaciation that 

has extensive till and constructional topographic 

features remaining. The Bull Lake icecap was 

somewhat larger than the succeeding Pinedale icecap, 

and large areas underlain by Bull Lake Till are fo~nd 

in the western part of the park (U.S. Geological 

Survey, 1972). Bull Lake Till underlies wood-bearing 

lake sediments dated at greater than 42,000 years 

B.P. (before present) and greater than 45,000 years 

B.P. in the Yellowstone Lake basin (Richmond, 1969c, 

1970a). 

Pinedale Glaciation is estimated to have begun 

about 25,000 years ago and stagnated about 

14,500-13,000 years ago in the Yellowstone National 

Park region (Richmond, 1970a, b; Waddington and 

Wright, 1974). The Pinedale icecap centered along a 

north-south axis through Yellowstone Lake (Richmond and Pierce, 1968, 1972; Richmond, 1969c). Ice 

flowed radially from the lake area to the north, to the 

east through divides in the Absaroka Range, and to 

the south and southwest across the rugged plateaus 

and ridges. As the Pinedale icecap melted, local 

ice-marginal lakes and kame terraces formed in the 

northeastern part of the Yellowstone Lake basin and 

gradually extended southward (Richmond, 1969a; 

U.S. Geological Survey, 1972). Channels carried the 

melt water away from the basin at several points 

around the lake (Richmond, 1969a). In the coring area 

a kame terrace formed along the lower slopes at the 

northwest margin of the Two Ocean Plateau (fig. 5, 

phase 1). Later, large ice blocks calved off, became 

buried by outwash and lake sediments, and formed 

kettles approximately parallel to the ice margin 

(locations shown in fig. 5, phase 2). 

After the Pinedale icecap had melted, cirque and 

valley glaciers readvanced in the Absaroka Range and 

on the Two Ocean Plateau (Richmond and Pierce, 

1972). Some valley glaciers were 5 miles long, and 

their terminal moraines (fig. 1) reached elevations as 

low as 7,880 feet, but averaged 8,400 feet (Richmond, 

1969b). Outwash terraces extended from these 

moraines down the valleys to a level about 60 feet 

above Yellowstone Lake. Lake sediments beneath a 

delta that graded to the 60-foot level at Grouse Creek 

on the South Arm of Yellowstone Lake were dated at 

9,060 ± 300 years B.P. (Sullivan and others, 1970, 

sample W- 2041; Richmond, 1970a). The coring sites 

were not glaciated and apparently received no glacierderived sediments at this time. 

An interval of maximum warmth and dryness (the 

Altithermal interval) is recognized in the Rocky 

Mountain area following the retreat of late Pinedale 

ice (Richmond, 1965, p. 227). Antevs (1955) placed the 

Altithermal interval between 7,500 and 4,000 years 

B.P.; however, these boundaries have not been 

consistently used, and they may transgress time. 

Valley and cirque glaciers apparently retreated during 

this warm period. 

Neoglaciation is the period of glacier expansion 

following the Altithermal period and extending to the 

present time. In the Rocky Mountain region it has 

been divided into the Temple Lake Stade, thought to 

have formed moraines about 2,800 years B.P. 

(Richmond, 1969b), and the Gannett Peak Stade, 

which began about 700 years ago and continues 

to the present (Porter and Denton, 1967, p. 201). 

Recently, however, Birkeland and Miller (1973), 

Miller and Birkeland (1974), and Currey (1974) showed 

that the type section of the Temple Lake in the Wind 

River Range is pre-Altithermal and may be late 

Pinedale in age. A new type section and name should 

be chosen for this 2,800-year-old glacial advance. 

Hence, the report will use the term "early 

neoglacial," rather than "Temple Lakes." In the 

Absaroka Range the average elevation is 9,460 feet for 

early neoglacial end moraines and 9,845 feet for 

Gannett Peak end moraines (Richmond, 1969b). 

Recent evidence suggests that some areas 

experienced glacial expansion as early as 5,000 years 

ago (Porter and Denton, 1967, p. 198). No moraines of 

this age are recognized in Yellowstone National Park, 
E6 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

but radiocarbon dates are lacking. The pollen record 

suggests that post-Altithermal cooling began at about 

that time. Neoglaciation in the park could thus include 

all sediments younger than 5,000 years. This usage is 

consistent with a recent definition of N eoglaciation 

(Porter and Denton, 1967, p. 205): "We • • • define 

Neoglaciation as the climatic episode characterized by 

rebirth and/ or growth of glaciers following maximum 

shrinkage during the Hypsithermal (Altithermal) 

interval." Neoglaciation is a geologic-climate unit. 

Boundaries of such units need not be isochronous (Am. 

Comm. Strat. Nomenclature, 1961, p. 660). 

Nearly continuous shorelines that locally grade into 

kame deposits are found around the south shore of 

/ 

PHASE 1 ------,~o<Y. / 

( 

KAME DEPOSITION _..J,.:;:_'7 I 

\ 

I PRE-11,550 YEARS B.P. 1 '\ '-~-?0 I \ '\tQ 

\ I ~,; 

\.; 'f ..... I 

/ 

----

PHASE 3 -------~o<Y. / '1&,.1} 

60-FOOT LAKE LEVEL /(.',.r: I 

5,590-10,360 YEARS B.P. ( \ <>o,., \ \ I v-". ) 

\ I '~ / \_1 '-....... ______ / 

0 

0 

./ 

/ 

1000 

250 

Yellowstone Lake at about 110 and 90 feet above 

modern lake level. The rarity at these levels of spits 

and bars, whose formation depends on a large fetch, 

suggests that the lake was not entirely open at this 

time (Richmond, 1969a). The 110-foot shoreline is not 

preserved in the coring area, but Trail Creek pond 

was a shallow lagoon that formed behind the 90-foot 

beach (fig. 5, phase 2, and fig. 7). Peat from this 

lagoon is 10,360 ± 350 years B.P. (sample W- 2289). 

The 90-foot lake level is probably older than this date 

because the peat sampled lies an undetermined 

distance above the basal organic sediments, and the 

break between sand of the lagoon floor and basal 

organic sediments may represent a diastem. This 

'- /// 

PHASE 2 ,..._ ______ ~o<Y. I 

90-FOOT LAKE LEVEL _)~(~.r: ~ PRE-10,360 YEARS B.P. \ \ ~~(Q/.· \ 

\ I ,,_,(Q I 

\ .. ../ "-............. ___ // 

... ------... 

....... // 

PHASE 4 ....... ..._ _____ Itt. I 

----'o<Y. I 

25-FOOT LAKE LEVEL \~'7 \ 

5,390 YEARS B.P. ( '-~'%>,., \ 

\ ~, ) \ '-) I '(Q ........ ____ ,...., // 

Trail Creek 

pond 

' .. :: ..... ~ 

N 

I 2000 3000 FEET 

500 METRES 

FIGURE 5.-Geomorphic development of coring area as glacier ice melted and lake level fell. Numbers in kettles indicate height of 

"baymouth bars," in feet above present lake level, that protected the lagoons and controlled their formation. 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E7 

90-foot lagoon probably formed during retreat of 

middle Pinedale ice; the organic sediment may have 

formed in part during the late Pinedale advance. 

Lower shorelines at 60, 40, 25, 15, 10, and 5 feet 

above modern lake level have associated large spits, 

bars, and lagoons similar in size to modern ones. 

Richmond (1969a) concluded that these lower beaches 

formed in an open, ice-free Yellowstone Lake after the 

icecap had entirely melted because the lower 

shorelines are cut into kame deposits and do not grade 

into them. 

The 60-foot shoreline correlates with a glacial 

advance (late Pinedale of Richmond, 1970b; Birkeland 

and others, 1971) that ended about 9,000 years B.P. in 

Yellowstone National Park. When the lake was at the 

60-foot level, rims of kettles must have projected 

above water to form isolated bays in the coring area 

(fig. 5, phase 3). 

Subsequent lowering of lake level converted 

Lilypad pond, Buckbean fen, and other kettles to 

lagoons and finally to isolated ponds (fig. 5, phase 4). 

Radiocarbon dates of 5,590 ± 250 years B. P. (sample 

W- 2286) from Lilypad pond and 5,390 ± 250 years B. 

P. (sample W- 2281) from Buckbean fen indicate that 

lake level had fallen below these lagoons before about 

5,500 years ago. The late Pinedale and younger levels 

were apparently controlled by erosion of glacial drift 

along the Yellowstone River (Richmond, 1969a). 

VEGETATION OF YELLOWSTONE 

NATIONAL PARK AND 

SURROUNDING AREA 

Yellowstone National Park has distinct elevational 

zonation of vegetation similar to that of other parts of 

the Rocky Mountain region (Daubenmire, 1943). Five 

broad vegetation zones, herein called vegetation 

associations, are briefly discussed. Scientific names of 

plants, and common names if available, are listed in 

table 1. 

TABLE 1. -Scientific names, and common names if avaiW.ble, of 

pW.nt taxa mentioned in text, tables, and iUustrations 

[(p), pollen or spores of the taxon were found; (m), macrofossils of the taxon were found] 

Scientific name and author Common name, if available 

DIVISION CHOLOROPHYTA 

HYDRODICTYACEAE 

lm) Pediastrum 

DIVISION CHAROPHYTA 

CHARACEAE 

(m) Ohara 

DIVISION BRYOPHYTA--------------------- Mosses 

TABLE !.-Scientific names, and common names if avaiW.ble, of 

pW.nt taxa mentioned in text, tables, and iUustrations-Continued 

Scientific name and author 

DIVISION BRYOPHYTA-Continued 

AULACOMNIACEAE 

(m) Aulacomnium palustre 

(W. & M.) Schw. 

HYPNACEAE 

C1i.macium dendroides 

(Hedw.) W. & M. 

(m) Drepanocw.dus 

LESKEACEAE 

Helodium bW.ndowii 

(W. & M.) Warnst. 

SPHAGNACEAE 

Common name, if available 

(m) Sphagnum·-------------------- Sphagnum moss 

(m?) Sphagnum warnstorfianum 

Dr. 

DIVISION PTERIDOPHYTES 

EQUISETACEAE 

(p) Equisetum ------------------- Horsetail 

ISOETACEAE 

Isoetes -·----------------------- Quillwort 

SELAGINELLACEAE 

(p) SelagineUa densa Rydb. --- Rock selaginella 

Selagi1teUa seW.ginoides 

(L.) Link 

POLYPODIACEAE 

(p) ---------------------------------- Fern 

DIVISION SPERMATOPHYTA 

CUPRESSACEAE 

(p) Juniperus 

(p)?(m)Juniperus communis L. --- Common juniper 

Juniperus virg,"niana L. 

PINACEAE 

var. scopulorum 

Lemmon-------------------- Redcedar, Rocky 

Mountain juniper 

(p) (m) Abies W.Siocarpa 

(Hook.) Nutt. ------------- Subalpine fir 

(p) (m) Picea engelmannii 

(Parry) Engelm.---------- Engelmann spruce 

Picea pungens Engelm. --- Colorado blue spruce 

(p) (m) Pinus albicaulis Engelm. -- Whitebark pine 

(p) (m) P'"nus contorta Dougl. ----- Lodgepole pine 

(p)? Pinus flexilis James -------- Limber pine 

(p)? Ps"nus ponderosa Laws.---- Ponderosa pine 

(p) (m) Pseudotsuga menziesii 

(Mirb.) Franco------------ Douglas-fir 

(p) Tsuga heterophyUa 

(Rafn.) Sarg. -------------- Western hemlock 

(p) Tsuga mertensiana 

(Bong.) Carr.-------------- Mountain hemlock 

EPHEDRACEAE 

(p) Ephedra torreyana S. Wats. 

(p) Ephedra viridis Coville---- Green jointfir 

ACERACEAE 

(p) Acer ---------------------------- Maple 

(p) AMARANTHACEAE 

BETULACEAE 

(p) (m) Alnus tenuifo/i,a Nutt. ----- Thinleaf alder 
EB GEOLOGY OF, YELLOWSTONE NATIONAL PARK 

TABLE !.-Scientific names, and common names if available, of 

plant taxa mentioned in text, tables, and iUustrations-Continued 

Scientific name and author Common name, if availllble 

DIVISION SPERMATOPHYTA-Continued 

BETULACEAE-Continued 

(p) Betula-------------------------- Birch 

(p) (m) Betula glandulosa 

Michx. ---------------------- Bog birch 

(p)? Betula occidentalis 

Hook. ----------------------- River birch 

BORAGINACEAE 

Mertensia --------------------- Bluebell, 

chiming bells 

CALLITRICHACEAE 

CaUitricke--------------------- Water-starwort 

CAMPANULACEAE 

Campanula rotundifolia 

L. ---------------------------- Common harebell 

CAPRIFOLIACEAE 

(p) ---------------------------------- Honeysuckle family 

(p) CARYOPHYLLACEAE 

CERATOPHYLLACEAE 

(m) CeratopkyUum demersum 

L. ---------------------------- }Jornwort 

(p) CHENOPODIACEAE 

(p)? Atriplex sp.------------------ Saltbush 

(p) Sarcobatus vermiculatus 

(Hook.) Torr.-------------- Greasewood 

(p) CHENOPODIACEAEAMARANTHACEAE ----------------- Cheno-Ams 

COMPO SITAE 

(p) Subfamily Tubuliflorae 

AckiUea lanulosa Nutt. ---- Yarrow 

(p) Ambrosia --------------------- Ragweed 

Antennaria ------------------- Pussytoes 

(p) Artemisia--------------------- Sagebrush 

(p) Artemisia tridentata 

Nutt. ------------------------ Big sagebrush 

Aster 

Ckrysotkamnus ------------- Rabbitbrush 

(p)? Franseria --------------------- Sand bur 

(p) Subfamily Liguliflorae 

CRASSULACEAE 

Sedum lanceolatum Torr. Stonecrop 

(m) Sedum rkodantkum Gray Rosecrown 

Sedum rosea (L.) Scop. ssp. 

integrifolium (Raf.) 

Hulten ---------------------- Kings Crown 

(p) CRUCIFERAE 

Arabis ------------------------- Rockcress 

Arabis glabra (L.) Bernh. Tower mustard 

(m) Descurainia califomica 

(A. Gray) Schulz --------- Tansymustard 

(m) Rorippa islandica (Oeder) 

Borbas ---------------------- Marshcress 

ELEAGNACEAE 

(p) Skepkerdia canadensis 

(L.) Nutt. ------------------ Buffaloberry 

ERICACEAE 

Arctostaphylos uva-ursi 

(L.) Spreng.--------------- Kinnikinnik, 

bearberry 

TABLE 1.-Scienti/ic names, and common names if available, of 

plant taxa mentioned in text, table, and iUustrations-Continued 

Scientific name and author 

DIVISION SPERMATOPHYTA-Continued 

ERICACEAE-Continued 

Common name, if availllble 

Kalmiapolifolia Wang.---- Swamp laurel 

Ledum glandulosum 

Nutt. 

PkyUodoce empetriformis 

(Smith) D. Don----------- Mountainheath 

Vaccinium myrtiUus L. ---- Myrtle blueberry 

FAGACEAE 

(p) Quercus ----------------------- Oak 

GENTIANACEAE 

Gentianopsis tkermalis 

(0. Kuntze) litis 

(=Gentiana tkermalis 

Kuntze)·------------------ Rocky Mountain 

fringed gentian 

HALORAGACEAE 

(m) MyriopkyUum 

(m)? MyriopkyUum spicatum L. 

ssp. exalbescens (Fern.) 

Hulb~n ---------------------- Watermilfoil 

(m)? MyriopkyUum verticilUJ.tum 

L. ---------------------------- Greenmilfoil 

HYDROPHYLLACEAE 

Pkacelia ----------------------- Scorpion-weed 

JUGLANDACEAE 

(p) Juglans ------------------------ Walnut 

(p) LEGUMINOSAE 

Lupt"nus argenteus 

Pursh. ---------------------- Silvery lupine 

LENTIBULARIACEAE 

Utricularia minor L.-------- Small bladderwort 

Utricularia vulgaris L.----- Common bladderwort 

LORANTHACEAE 

(p) Arceutkobium 

(p)? Arceutkobium americanum 

Nutt. ------------------------ Lodgepole pine dwarf 

mistletoe 

Arceutkobium campylopodum Engelm. ---------- Western dwarf 

mistletoe 

Arceutkobium douglasii 

Engelm. -------------------- Douglas-fir dwarf 

mistletoe 

MENYANTHACEAE 

(p) (m) Menyantkes trifoliata L. -- Buckbean 

NYMPHAEACEAE 

(p) (m) Nupkar luteum 

OLEACEAE 

Sibth. & Sm. ssp. 

polysepalum (Engelm.) 

Beal-------------------------- Yellow pond lily 

(p) Fraxt"nus ---------------------- Ash 

(p) ONAGRACEAE 

(m)? Epilobium adenocaulon 

Hausskn. 

(m)? Epilobium glandulosum 

Lehm. 

(m) Epilobium lactiflorum 

Hausskn. ------------------- Pale willow-herb 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E9 

TABLE 1-Scienti.fic names, and common names if available, of 

pln.nt taxa mentioned in text, tables, and iUustrations-Continued 

Scientific name and author Common name, if available 

DIVISION SPERMATOPHYTA-Continued 

PLATAGINACEAE 

(p) Plantago----------------------- Plantain 

POLEMONIACEAE 

Phlox multijloro 

A. Nels. -------------------- Common phlox 

(p) Polemonium ------------------ Jacobs ladder 

POLYGONACEAE 

(p) Bistorta 

(p) Bistorta bistortoides 

(Pursb.) Small (=Polygonum bistortoides 

Pursh) ---------------------- Bistort 

(p)? Bistorta vivipara (L.) 

S. Gray (=Polygonum 

vivipan~,m L.) ------------- Viviparous bistort 

(p) Eriogonum-------------------- Umbrellaplant 

(p) Koenigia islandica L. 

(p) Oxyria ------------------------- Alpine sorrel 

(p)? Persicaria amphibia (L.) 

S. Gray Water smartweed 

( =Polygonum amphibium 

L.) 

(p)? Persicaromaculata (Raf.) 

S. Gray Ladysthumb 

( =Polygonum persicaria 

L.) 

(p)? Polygonum ramosissimum 

Michx. ---------------------- Busby knotweed 

(p) Rumex------------------------- Dock 

(p)?(m)Rumex fu,eginus Phil.------ Golden dock 

(=Rumexmaritimus L. 

var.fu,eginus (Phil.) 

Dusen) 

Rumex paucifolius Nutt. 

(p)?(m)Rumex salicifolius Weinm. 

ssp. triangulivalvis 

Danser---------------------- Willow dock 

RANUNCULACEAE 

Aconitum columbianum 

Nutt. ------------------------ Monkshood 

Anemone multi/ida Pair. 

var. globosa (Nutt.) 

T & G.----------------------- Globose anemone 

(p) Ranunculus 

(m) Ranunculus aquatilis L. --- Water crowfoot 

(p) Tha/ictn~,m-------------------- Meadow rue 

RHAMNACEAE 

(p)? Ceanothus velutinus 

, . Dougl.----------------------- Sticky-laurel 

(p) ROSACEAE 

(p )? Cercocarpus ------------------ Mountainmahogany 

Fragaria----------------------- Strawberry 

Geum macrophyUum 

Willd. ----------------------- Large-leaf avens 

PentaphyUoides jloribunda 

(Pursb) A. Love---------- Shrubby cinquefoil 

(=PotentiUafru,ticosa L.) 

(m)? PotentiUa biennis Greene 

(m)? PotentiUa gracilis Dougl. 

ex. Hook.------------------- Soft cinquefoil 

TABLE 1.-Scienti.fic names, and common names if available, of 

pln.nt taxa mentioned in text, tables, and iUustrations-Contin-ued 

Scientific name and author Common name, if available 

DIVISION SPERMATOPHYTA-Continued 

(p) ROSACEAE-Continued 

(m)? Potentilla norvegica L. ---- Norway cinquefoil 

(p)?(m)PotentiUa palustris (L.) 

Scop. ------------------------ Marsh cinquefoil 

(m) SibbaUlia procumbens L. 

RUBIACEAE 

Galium trifidum L.---------- Small bedstraw 

SALICACEAE 

(p) Populus 

(p)?(m)Populus balsamifera L. ---- Balsam poplar 

Populus tremuloides 

Michx. ---------------------- Quaking aspen 

Populus trichocarpa 

Torr. and Gray ----------- Black cottonwood 

(p) Salix---------------------------- Willow 

Salix arctica Pallas. 

Salix ligu,lifolia (Ball) Ball 

(m)? Salix subcoerulea Piper --- Blue willow 

SAXIFRAGACEAE 

(ui) Saxifraga caespitosa L.---- Matted saxifrage 

(m) Saxifraga rhomboidea 

Greene---------------------- Diamondleaf 

saxifrage 

(p)? SCROPHULARIACEAE 

(p)? Pedicularis 

Pedicularis groenlandica 

Retz ------------------------- Elepbantella 

(p)? Mimulus ----------------------- Monkey flower 

(p) UMBELLIFERAE 

URTICACEAE 

(p) Urtica -------------------------- Nettle 

(p) CYPERACEAE 

(m) Carex aquatilis Wablenb. 

(m) Carex canescens L. 

(m) Carex diandra Schrank 

Carex geyeri Boott 

Carex hoodii Boott 

(m) Carex li'mosa L. 

Carex phaeocephala Piper 

(m) Carex utriculata Boott 

(=Carex rostrata Stokes) 

(m) Carex vesicaria L. 

(m) Eleocharis macrostachya 

Britt.------------------------ Spikerush 

Erioph0n1,m ------------------ Cottongrass 

Scirpus acutus Muhl.------- Hardstem bulrush 

(p) GRAMINEAE 

Agropyron-------------------- Wheatgrass 

Bromus ------------------------ Bromegrass 

Bromus inermis Leyss. ---- Smooth brome 

Calamagrostis canadensis 

(Micbx.) Beauv. ---------- Bluejointgrass 

Cala:magrostis inexpansa 

A. Gray--------------------- Northern reedgrass 

Deschampsia caespitosa 

(L.) Beauv. ---------------- Tufted bairgrass 

. Elymus ------------------------ Wild-rye 

Glyceria borealis (Nash) 

Batchelder----------------- Northern mannagrass 
E10 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

TABLE 1.-Scientijic names, and common names if avaiWhle, of 

pW.nt taxa mentioned in text, tables, and iUustrotions-Continued 

DIVISION SPERMATOPHYTA-Continued 

(p) GRAMINEAE-Continued 

(m) Glyceria maxima (Hartm.) 

Holmb. ssp. grandis 

(Wats.) Hulten 

( =Glyceria grondis 

Common name, if available 

S. W ats.) ------------------- Large manna grass 

Poa ----------------------------- Bluegrass 

Sitanion longifolium J. G. 

Smith ----------------------- Squirrel-tail 

(=Sitanion hystrix 

(Nutt.) J. G. Smith) 

Stipa --------------------------- Needlegrass 

JUNCACEAE 

L'UZ'Ula parvijlora (Ehrh.) 

Desv. ------------------------ W oodrush 

LuzuUJ. spicata (L.) DC.---- Spike woodrush 

NAIADACEAE 

(m) Naias flexilis (Willd.) 

Rostk. and Schmidt----- Naiad 

(m) Potamogeton alpinus 

Balbis ----------------------- Northern pondweed 

(m) Potamogeton filiformis 

Pers. 

(m) Potamogeton gram,"neus L. 

(m)? Potamogeton iUinoensis 

Morong 

Potamogeton pecUnatus 

L. ---------------------------- Sago pond weed 

Potamogeton vaginatus 

Turcz. 

SP ARGANIACEAE 

(p)? Sparganium 

Sparganium angustifolium Michx. ------------- Burreed 

Sparganium mim"mum 

Fries ------------------------ Arctic burreed 

TYPHACEAE 

(p)? Typha angustifolia L. ------ Narrowleafed cattail 

(p) Typha W.tifolia L.------------ Broadleaf cattail 

REGIONAL VEGETATION 

ARTEMISIA STEPPE ASSOCIATION 

The lowest vegetation type in the park is Artemisia 

(sagebrush) steppe at the base of the north edge of the 

Yellowstone plateau (fig. 6). Artemisia tridentata is 

the dominant plant in this association, but Sarcobatus 

vermiculatus (greasewood) and Atriplex spp. 

(saltbush) are common on clayey or alkaline sites, and 

in many places Ckrysotkamnus spp. are scattered 

among the sagebrush. Grasses including Elymus spp. 

(wild-rye) and Bromus spp. (bromegrass) are locally 

common. This type occurs between Mammoth and 

Gardiner in the northern part of the park and is 

common around the margins of the park below about 

6,000 feet. Large areas of Artemisia steppe on the 

Snake River Plain southwest of the park may be an 

important source of Artemisia pollen. 

The lower limit of trees above the Artemisia steppe 

is highly variable because of local factors. Near 

Mammoth, it ranges from about 5,800 to 6,800 feet. 

East of the park in the rain shadow of the Absaroka 

Range it is 6,500-7,600 feet (H. E. Wright Jr., 

unpub. data, 1967). At Mammoth it is associated with 

a mean annual temperature of about 40°F, mean 

January temperature of 18°F, mean July temperature 

of 63°F, and mean annual precipitation of 15.5 inches. 

Artemisia tridentata (big sagebrush) also dominates in forest openings up to several acres in size on 

the Yellowstone plateau, where it is more stunted 

than at lower elevations. In the southeast corner of 

the park, these Artemisia openings occur on dry 

south-facing slopes adjacent to the Southeast Arm of 

Yellowstone Lake (fig. 3). They occur locally on 

south-facing slopes of Buckbean fen and adjacent 

lagoons (fig. 7). 

Plants associated with Artemisia in the southeast 

part of the park include Eriogonum subalpinum 

(umbrellaplant), Lupinus argenteus (silvery lupine), 

Achillea lanutosa (yarrow), Antennaria sp. (pussytoes), Pkacelia sp. (scorpion-weed), Arabis glabra 

(rockcress), Phlox multiflora (common phlox), Carex 

koodii (sedge), Carex petasata (sedge), Agropyron 

spp. (wheatgrass), Stipa spp. (needlegrass), Bromus 

inermis (bromegrass), Campanula rotundifolia 

(common harebell), Sitanion kystrix (squirrel-tail), ~. 

and Arctostaphylos uva-ursi (kinnikinnick). Artemisia 

tridentata in this community may have been an 

important supplier of Artemisia pollen in the fossil 

record. 

PSEUDOTSUGA ASSOCIATION 

Pseudotsuga menziesii (Douglas-fir) is dominant in 

the next lowest vegetation association but is sporadic 

in occurrence in the Yellowstone region. Locally Pinus 

flexilis (limber pine) and Populus tremuloides 

(quaking aspen) are common in this association. Pinus 

ponderosa (ponderosa pine), which normally occurs in 

this elevational zone, is not present in northwestern 

Wyoming (Choate, 1963). Juniperus virginiana var. 

scopulorum (Rocky Mountain juniper) occurs at lower 

elevations along the forest-steppe boundary. 

Pseudotsuga menziesii is not common on the 

Yellowstone plateau, but it grows sparsely about 6 

miles north of the coring sites and on the east slope of 

the Absaroka Range about 12 miles to the east. 

The Pseudotsuga association grows as low as 6,000 

feet in an open savanna, along stream valleys, and in 

closed forests as high as about 8,000 feet (H. E. 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN 

0 2 3 4 5 Ml LES 

0 2 3 4 5 KILOMETRES 

CONTOUR INTERVA L 1000 FEET 

EXPLANATION 

CB Pinus contorca 

D Picea-A bies-Pinus albicau/is 

~~t~~j Pseudotsuga 

Artemisia 

D Alpine 

D Carex-Sa lix 

Ell 

FIGURE 6.-Vegetation map of the southeast corner of Yellowstone National Park. The hachured line is 110 feet above Yellowstone Lake; 

it shows the highest lake level interpolated from the base maps. Contacts between vegetation units are approximate and are not 

marked by lines. In part from unpublished map of vegetation of Yellowstone National Park by National Park Service. Base from U.S. 

Geological Survey Eagle Peak, Frank Island, Mount Hancock, and Two Ocean Pass 1:62,500 topographic quadrangles, 1959. 
E12 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

Wright J~., unpub. data, 1973). No climatological data 

were available for this association. 

PINUS CONTORTA FOREST ASSOC!ATION 

The Pinus contorta (lodgepole pine) forest is by far 

the most common vegetation type in Yellowstone 

National Park. It covers about 80 percent of the total 

forested area (National Park Service, unpub. data). 

Picea engelmannii (Engelmann spruce) and Abies 

lJLsiocarpa (subalpine fir) grow in the upper part of this 

type. Most Pinus contorta forests are open and dry 

and contain little underbrush, and they commonly 

grow on porous grus soils. Near the coring sites the 

common understory plants are Juniperus communis 

(common juniper), Shepherdia canadensis (buffaloberry), Vaccinium myrtillus (myrtle blueberry), 

Arctostaphylos uva-ursi, Eriogonum subalpinum, 

Arabis spp., and various composites and grasses. 

Pinus contorta is more dominant on the flat plateau 

areas of the park than in the dissected southeast 

corner, but it still is the most ~~-nmon tree in the 

southeast corner (fig. 3). 

Pinus contorta forests are usually found between 

7,000 and 8,500 feet (McDougall and Baggley, 1956). 

They are best developed where annual precipitation 

exceeds 18- 21 inches, growing season is short 

(60 -100 days), and mean July temperature is 

55° - 63°F (Tackle, 1961). 

Pinus contorta spreads rapidly after fires (Porter, 

1962; Tackle, 1961) and is commonly said to be a 

successional tree. Tackle believed that it is a climax 

species in some areas, and some of the forest in the 

park appear to be climax. Kuehler (1964) mapped 

Yellowstone National Park as potentially a 

Pseudotsuga climax forest, but the scarcity of 

Pseudotsuga on the Yellowstone plateau and the 

relatively high precipitation and cool summers there 

argue for Picea-Abies as more probable potential 

climax species in the absence of fire. On the average, 

32 fires, mostly small ones, occur in the park every 

year (National Park Service, unpub. data). In the 

northern part of the park, Houston (1973) estimated 

that 8 - 10 extensive fires have occurred in the last 

300- 400 years. Judged from the abundance of 

charcoal in cores and in some exposures, fires have 

been common throughout postglacial time. Large fires 

occurred in 1931 (a dry year) and 1940 in the southern 

part of the park. 

PICEA-ABIES-PINUS ALBICA ULIS 

FOREST ASSOCIATION 

The Picea-Abies-Pinus albicaulis forest occurs 

throughout the park above the Pinus contorta forest. 

In the southeastern corner of the park, this association 

occurs on most of the Two Ocean Plateau (fig. 6) and in 

the high parts of the Absaroka Hange. Picea and Abies 

also occur in some areas along the lake, probably 

because in summer the lake creates a cooling effect 

around its margin. This forest also grows along the 

north-facing slopes of the Two Ocean Plateau close to 

the coring sites (fig. 6). 

Picea engelmannii (Engelmann spruce) and Abies 

lJLsiocarpa (subalpine fir) are the dominant trees of this 

type. In many places Pinus albicaulis (white bark pine) 

is an associate, especially at higher elevations or in 

dry rocky or porous soils. Pinus contorta is commonly 

associated with Picea and Abies below 8,500 feet, and 

Populus tremuloides ( quaking aspen) is occasionally 

present. The understory commonly includes Carex 

geyeri (sedge), Luzula parviflora (woodrush), 

Juniperus communis, Vaccinium spp., Mertensia spp. 

(bluebell), Aconitum columbianum (monkshood) and 

Lupinus argenteus. ' 

Picea-Abies-Pinus albicaulis forests occur from 

about 8,500 feet to treeline in the park. Treeline is 

about 9,200-9,800 feet in the Absaroka Range and 

9,400 -10,000 feet on the Two Ocean Plateau. In the 

Yellowstone National Park region the Picea-AbiesPinus albicaulis forest is probably best developed 

where mean annual temperatures are 30°F- 35°F, 

mean January temperatures are 5°F- 15°F, mean 

July temperatures are 45°F- 55°F, and mean annual 

precipitation is 25 - 35 inches. 

ALPINE ASSOCIATION 

Alpine vegetation is developed more extensively 

on the Beartooth Plateau, northeast of Yellowstone 

National Park (Porter, 1962; Johnson and Billings, 

1962), but it also occurs on high areas in the park 

including the Absaroka Range and the Two Ocean 

Plateau (fig. 6). 

Gramineae (Grass family), Cyperaeeae (Sedge 

family), and J uneaeeae (Rush family) are abundant in 

alpine areas of the park as are many other perennial 

herbs. In the southeast corner of the park, the most 

·common perennial plants include Bistorta vivipara 

(viviparous bistort), Bistorta bistortoides (bistort), 

Polemonium spp. (Jacobs ladder), PotentiUa spp. 

(cinquefoil), Salix arctica (arctic willow), Saxifraga 

rhomboidea ( diamondleaf saxifrage), Saxifraga caespitosa (matted saxifrage), and SelagineUa densa (small 

elubmoss). 

Alpine vegetation is found from about 9,200 - 9,800 

feet up to the highest peaks. No climatic data are 

available for the alpine association in Wyoming. At 

the University of Colorado's alpine climatic station in 

the Front Range at 12,300 feet, the mean annual, 

mean January, and mean July temperatures 

were. respectively, 26°, 7°, and 47°F, some 7° -10°F 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E13 

cooler than at the subalpine station at 10,000 feet for 

the years 1953 - 64 (Marr and others, 1968). Precipitation averaged about 26 inches annually at the 

subalpine and the alpine stations in Colorado for the 

years 1953-64. 

LOCAL VEGETATION AROUND 

THE CORING SITES 

A reconnaissance map of the local vegetation was 

made in early September, 1966 and 1967. Four mesic 

to xeric communities and five semiaquatic communi-

. . .. .. . 

. . _ ... .. ......... : 

o ,o 

. . . . . . . 

44° 

17' 

30" ·.:: 

·.·: : :· 

.. '•o 

·. -~ ~ : . : : : . .·. ·. ·· 

.· ...... 

·.·.·.·.· . .. 

·:: .. ::: . :: · ...... . . : . 

.·:.:.·: · · .. ·.· . · ·.· .·.· 

-:.:::· . . . . : .. . : ·. :' : ~ :":. ·. : .. ... . 

·.··:·:.·:·: · · 

·.· .... ·.·.;:· . .... . 

· ... ·.· ·. 

0 

0 

1000 

250 

ties (herein called vegetation types) are recognized 

(fig. 7). Of the mesic to xeric communities, Pinus 

contorta forest surrounds the coring area, and PiceaAbies-Pinus albicaulis forest grows down to the base 

of the steep slope along the north edge of the Two 

Ocean Plateau (fig. 7). Grass-forb meadows grow on 

gentle slopes underlain by silty lake sediments, and 

Artemisia openings occur on south-facing steeper 

slopes underlain by gravel (fig. 7). The two forest 

types and the Artemisia openings are predominant in 

the regional vegetation and were discussed in the 

2000 

500 METRES 

Sowh eas1 Arm 

Yellows/on e Lak e 

3000 FEET 

·-::: 

• 0 • 

. . . . . . . . . :: ... _: ·.:: ~ · .. : ': ': .. ·. : . ·.·.· ... . . .... · ·:-· . . : · ... ~. :. >~ ........ ..... . · ·. ·: ·: :· .. . . .·. ·. ·.·.·.·.·.: .. . 

··.· .·.··.'::'. ·.··. :·.' · 

. ·.·.::-· · .. •, . .... · ... . • o. 

0 0 • 

. ·.· .. ·. ::·:·."· 

EXPLAN ATION 

AQ ATIC A D DAMP-G ROU D VEGETATION 

(SEMIAQUATJC) 

UP AND VEGETATION 

(MES IC TO XER IC) 

Nuphar 0Potamogero11 (shal lo w-po nd aquatic) type .. :: ...... _. ~ .. ·. Pinus contorta forest 

Me11yantlies tnjoliata type Picea-A bies-Pinus albicau/i. forest 

Carex wriculaia fen Artemisia tride111a1a openi ngs 

Carex diandra-Polelltilla palustris fen Gramineae-forb mead ows 

Ca/amagrostis-Sa/ix-Sedum rliodan!hum type 

FiGU RE 7.- Map of local vege tation around coring sites, showing surface sample and core localities at Buckbean fen and Lilypad pond. 
E14 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

preceding section. Grass-forb meadows are locally 

common where lake silts are present. The five 

semiaquatic types are discussed in the following 

paragraphs. 

NUPHAR-POTAMOGETON TYPE 

This type is the only true aquatic community. It is 

found in ponds on Buckbean fen and Lilypad pond 

(figs. 7, 8, and 9). The aquatic flora contains Nuphar 

luteum ssp. polysepalum (yellow pond lily), 

Utricularia vulgaris (common bladderwort), U. minor 

(small bladderwort), Potamogeton alpinus (northern 

pondweed), and Potamogeton sp. (pondweed). Only 

two or three of these species usually occur in any one 

pond. 

MENY ANTHES TRIFOLIA TA TYPE 

The Menyanthes trifoliata type occurs locally only 

in Buckbean fen (fig. 7) and perhaps should be 

included in the Nuphar-Potamogeton type. It contains 

mainly Menyanthes trifoliata (buckbean) with 

occasional Carex utriculata (sedge). The dominant 

moss is Drepanocladus sp. These species grow on 

organic mud which was covered with a few inches of 

water in the fall in 1966 and 1967. The mudflats may 

be filled-in remnants of small ponds. 

CAR EX UTRICULA T A TYPE 

The Carex utriculata type is the most widespread of 

the fen communities (figs. 7, 8, and 10). Its habitat 

ranges from standing water to fairly dry peaty turf. 

Cu 

FIGURE 8.-Coring site (arrow) at Buckbean fen; viewed from the 

north. Vegetation types are Pinus contorta (Pc), Carex 

diandra -PotentiUa palustris (CP), Carex utriculata (Cu), which 

is 3-4 feet high, Nuphar- Potamogeton (NP), and Artemisia 

(A). 

FIGURE 9.-Closeup of small pond shown on left in figure 8. Vegetation types are Carex diandra -Potentilla palustris (CF 

Nuphar- Potamogeton (NP), Artemisia (A) opening in Pinus 

contorta (Pc) forest. Sedges in foreground are about 1 foot high. 

View to northwest. 

Carex utriculata is by far the dominant plant, with 

occasional Carex aquatilis, and rare Galium trifidum 

(small bedstraw), Salix ligulifolia, S. subcoerulea (blue 

willow), and Persicaria amphibia (water smartweed). 

The dominant moss is Drepanocladus sp. 

CAREX DIANDRA-POTENTILLA PALUSTRIS TYPE 

This fen community is one of the most distinctive of 

the semiaquatic communities (fig. 11). It is limited to 

the Buckbean fen. The fen had no standing water on it 

in late summer, 1966 and 1967, but the roots of the 

plants were in water-saturated peat. The dominant 

plants are Carex diandra, C. limosa, C. aquatilis, 

Potentilla palustris (marsh cinquefoil), Eriophorum 

FIGURE 10.-Carex utriculata type. Extensive poorly drained flats 

underlain by peat and covered by 3- to 4-foot-high sedges. 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E15 

FIGURE 11.- Carex diandra-PotentiUa palustris type. Poorly 

drained flats underlain by peat and covered by sedges and other 

forbs 0.5-2 feet high. 

sp. (cottongrass), with occasional Galium trifidum, 

Calamagrostis inexpansa (northern reedgrass), C. 

canadensis (bluejoint grass), Menyanthes trifoliata 

and Carex utriculata. The dominant moss is 

Drepanocladus sp. 

CALAMA GROSTIS-SALIX-SEDUM RHODANTHUM TYPE 

The community grows mainly around the margins of 

the depressions, though an impoverished form of this 

community grows on a gently sloping surface on the 

south part of Lilypad pond (fig. 7). This community is 

the richest of the semiaquatic communities. Common 

plants are Sedum rhodanthum (rosecrown), Pedicularis groenlandica (elephantella), Gentianopsis 

thermalis (Rocky Mountain fringed gentian), 

Anemone multifida (globose anemone), Salix 

subcoerulea, S. ligulifolia, Calamagrostis canadensis, 

C. inexpansa, Luzula parviflora, Carex canescens, and 

Aster spp., with occasional Pentaphylloides floribunda 

(shrubby cinquefoil), Bromus sp., Deschampsia 

caespitosa (tufted hairgrass), Luzula spicata (spike 

woodrush), Carex phaeocephala, and Geum macrophyUum (large-leaf avens). The dominant mosses are 

Climacium dendroides and in wetter places 

A ulacomnium palustre and H elodium blandowii. 

Drepanocladus sp. is less common in this community. 

OTHER PALEOBOTANICAL WORK 

IN THE AREA 

Three cores from nearby localities were recently 

analyzed for pollen (H. E. Wright, Jr., written 

commun., 1967; Waddington and Wright, 1970, 1974). 

One of these was taken at Cub Creek pond 12 miles 

west of the East Entrance to Yellowstone National 

Park (SS- 26 in fig. 12), where modern vegetation is 

similar to that of Buckbean fen. The other cores were 

collected from two ponds in steppe vegetation near 

Cody, Wyo. Cub Creek pond pollen curves closely 

resemble those from Buckbean fen and suggest a 

similar paleoecological history. A C 14 - date on pine, 

where it shows an abrupt increase at the boundary 

between the two major zones, is 11,630 ± 180 years 

B.P. (sample I- 2285). The record from the two ponds 

near Cody dates from after Altithermal time, and the 

sequences are difficult to correlate with that at 

Buckbean fen. 

Other Wyoming pollen diagrams are of cores taken 

from lower elevations and are dominated by steppe 

elements. R. C. Bright (written commun., 1967) has 

two unpublished diagrams from sites near Pinedale 

just south of the Wind River Range (fig. 12); one 

pollen sequence dates from late Pinedale to present 

time, and the other from middle Pinedale(?) to present 

time. Hansen (1951) reported two postglacial 

diagrams from the Eden Valley archeological site (fig. 

12). 

Bright (1966) discussed vegetation history inferred 

from pollen and plant macrofossil diagrams of cores 

from Swan Lake, west of Red Rock Pass, southeastern 

Idaho (fig. 12). Red Rock Pass also has a steppe 

vegetation at present, and the diagrams are 

dominated by pollen from steppe plants during postglacial time. The Swan Lake record extends back to 

about 12,000 years B.P. 

Elsewhere in the Rocky Mountains, pollen records 

have been published from Glacier National Park, 

Mont. (Hansen, 1948); from the Front Range, Colo., 

(Pennak, 1963; Maher, 1972); from the San Juan 

Mountains, Colo. (Maher, 1963); and from the Chuska 

Mountains, N. Mex.(Bent and Wright, 1963; Wright 

and others, 1973). Bent and Wright (1963) and Maher 

(1963) include pollen surface samples as well as 

fossil-pollen diagrams. 

POLLEN SURF ACE SAMPLES 

Pollen released by plants may be preserved in 

certain depositional environments. The pollen rain on 

any surface bears some relationship to the vegetation 

associations from which it is derived (Davis, 1965). If 

pollen rain and modern vegetation are known 

quantitatively, a transform function can be derived 

that will convert pollen percentages to numbers of 

plants growing in the region (Davis, 1963). If only the 

broad vegetational associations are known, as in 

Yellowstone National Park, these associations may be 

recognizable from their pollen rain, even though 

quantitative terms cannot be used. If fossil and 
E16 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

modern pollen assemblages are similar, it is assumed 

that they were derived from similar vegetation 

associations. Yellowstone National Park is well suited 

for comparison of surface pollen assemblages with 

fossil pollen assemblages because of its undisturbed 

vegetation and simplicity of forest composition. 

The relationship between the modern pollen rain 

and modern vegetation was examined for analogs for 

I 

•ss-5 

\ 

( 

\_ 

.ss-7 44oL-I ----'----"------------------_J_----' 

0 10 20 MILES 

0 10 20 30 Kl LOMETRES 

fl

•Beartooth Plateau MONTANA 

!--/""-- ----------

Cody 

Absaroka Range 

'3¥-0 ·(\,a- s(\ ~\'<>' Jackson Hole 

IDAHO I I o• Pinedale WYOM lNG 

I .s I 

~~:l I 

0 100MILES 

I I I 

0 100 KILOMETRES 

FIGURE 12.-Map of Yellowstone National Park, showing localities 

of surface samples and coring area. Surface sample SS - 26 is 

Cub Creek pond (Waddington and Wright, 1970). SS -12, -13, 

and -14 are surface samples from the coring area. Lower map 

shows location of other fossil pollen work: E, Eden Valley archeological site (Hansen, 1951); S, Swan Lake (Bright, 1966); D, Dew 

Lake (R. C. Bright, unpub. data, 1967). 

interpreting fossil pollen assemblages. Surface mud 

samples were collected for pollen analysis from ponds 

in the major vegetation associations of the park (fig. 

12; table 2). Where pond sediments were not available 

moss polsters were collected. A description of the 

vegetation association around each surface-sample 

site (table 2) aids in comparing the pollen rain with the 

vegetation associations. The results of the 

surface-sample study are plotted in figure 13. 

Pollen was prepared for analysis by taking about 

one cm3 of sediment and adding successively KOH, 

HCl, HF, HCl, and acetolysis solution (9 parts acetic 

anhydride + 1 part H2SO4 ) • The preparations were 

mounted in silicone oil (viscosity 12,000 centistokes) 

for preservation and counting. Pollen percentages are 

based on the sum of 300 or more grains (for most 

samples) of total terrestrial-plant pollen (fig. 13). 

SURFACE SAMPLES FROM THE 

ARTEMISIA STEPPE 

Pollen rain in the Artemisia steppe association near 

the north edge of the Yellowstone plateau is fairly 

distinctive (fig. 13). Pinus pollen percentages are 

lower (45- 60 percent) than almost anywhere else in 

the park, and Chenopodiaceae-Amaranthaceae (hereafter called Cheno-Ams) are abundant. Sarcobatus 

(greasewood) is nearly 20 percent in sample SS - 20 

and is absent in sample SS -21 (figs. 12 and 13). 

Artemisia pollen percentages are suprisingly low (less 

than 10 percent) considering that Artemisia tridentata 

grows abundantly at sites SS- 20 and SS - 21. 

Maher (1963) found low Artemisia percentages at 

low elevations near the San Juan Mountains, Colo., 

and H. E. Wright, Jr. (unpub. data, 1967) found 

similar results in the upper levels of cores near Cody, 

Wyo. Bright (1966). however, found 20-60 percent 

Artemisia and less than 10 percent Pinus in surface 

samples from a steppe region in southeastern Idaho. 

Bright's samples were from a largely unforested area 

of steppe, whereas the other samples were from 

steppe regions bordered by large forests. 

Pinus and Pice a pollen in the Artemisia steppe 

samples probably are the same species that occur at 

higher elevations in the park. The few grains of Picea 

pollen probably represent Picea engelmannii. Picea 

pungens (blue spruce), a spruce of lower elevations, is 

not abundant in the park, and McDougall and Baggley 

(1956) list only one record of it. The Pinus pollen 

represents mainly Pinus contorta type, though no 

attempt was made to differentiate Pinus ponderosa, 

which does not occur in northwest Wyoming and 

adjacent areas (Critchfield and Little, 1966). Pinus 

contorta type pollen is distinct from that of Pinus 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E17 

TABLE 2.-Locality and description of surface samples and coUection stations, Yellowstone National Park and vicinity 

No. in 

fig. 12 

(SS-) 

1 .. 

2 ... 

5 .. . 

7 ... . 

8 .. 

9 .\. 

12 .. 13. 

14. 

16. 

18. 

19 ........ . 20 .... . 

21 . 

22. 

23 

24 

25. 

26 ... 

27 .... 

28 .. 

29. 

30 .. 

33. 

34 

35 

36 .............. . 

38. 

39 ... 

Elevation 

(ft above 

sea level) 

7,840 

9,140 

8,660 

8,100 

7,860 

9,880 

7,750 

7,750 

7,750 

7,940 

10,000 

9,760 

5,360 

5,960 

6,800 

7,240 

7,560 

7,750 

8,200 

8,414 

8,466 

9,000 

9,080 

7,790 

7,780 

7,380 

6,880 

9,684 

9,640 

Locality 

North of Lake Lodge, north edge of Yellowstone Lake. 

Huckleberry Ridge 4.2 miles east of South Entrance. 

2.3 miles south of Fox Creek patrol cabin south of park 

boundary, at west edge of large burn area. Two Ocean Pass, south of the park. 

Near outlet at west end of Bridger Lake, in Yellowstone 

River valley 0.5 mile south of park boundary. 

Lake on Two Ocean Plateau between Phlox and Lynx 

Creeks and 3 miles north of south boundary of park. 

South edge of Buckbean fen (fig. 5). 

.... do ........................................ . 

Near north side of Buckbean fen (fig. 5). 

1.1 miles east of Beryl Sprin~ in Gibbon Canyon, south- east of Gibbon Geyser Basm. 

North side of Mount Washburn, along moist stream bank 

just above treeline. 

Northwest side of Mount Washburn; near generator. 

About 1 mile south of North Entrance of park. 

About 1 mile southeast of Mammoth near Gardner 

River. 

Hoodoos landslide area about 1 mile south of Mammoth. 

Swan Lake Flat, Gardners Hole southwest of Mammoth. 

South Twin Lake, north from Norris Junction. 

Squaw Lake on north edge of Yellowstone Lake. 

Cub Creek pond about 1.6 miles east of Yellowstone 

Lake along East Entrance Road (also site of Waddington 

and Wright's (1970) core). 

Southwest side Sylvan Lake, on East Entrance Road. 

Southeast end of Eleanor Lake on East Entrance Road. 

First pond on stream south of Eleanor Lake. 

Highest lake south of Eleanor Lake. 

Duck Lake near West Thumb. 

Lewis Lake. 

Small artificial(?) pond between road and Lewis Canyon 

about 3 miles north of South Entrance. 

Pond between road and Snake River 0.2 rriile north of 

South Entrance. 

Pond 1 mile northwest of Mount Schurz, Absaroka Range. 

Pond at southeast end of saddle southeast of Mount Langford, Absaroka Range (pond not shown on Eagle Peak 

quadrangle). 

Description 

Surface muds of small artificial pond. Forb meadow opening in Pinus contorta forest. 

Surface muds of small pond. Carex-Gramineae meadow in PiceaAbies parkland. Pinus albicaulis in nearby areas, but none at the 

site. 

Surface muds of small pond; pond surrounded by mosses and some Cyperaceae speci~s. forest was mixed Pinus contorta-Picea-Abies. Moss polster from large sedge fen. Fen with Carex utriculata, C. 

spp., and Salix spp., Pinus contorta locally up to 8,300 ft, but 

Picea-Abies-Pinus albicaulis forest on surrounding slopes. 

Surface muds; Carex fen surrounds outlet area; Pinus contorta dominates valley-bottom forest; Picea and Abies grow on higher 

valley slopes. Moss polster from margin of lake; alpine vegetation with PiceaAbies-Pinus albicaulis parkland on nearby slopes. 

Surface muds from Carex utriculata community. Moss polster from Calamagrostis-Salix-Sedum rhodanthum 

community. 

Surface muds from small pond. Surface peat from the core in the 

Buckbean fen; Carex diandra-Potentilla palustris fen. 

Surface muds of pond. Aquatics Nuphar, Potamogeton, and 

Callitriche in pond; narrow ring of Carex aquatilis and C. 

utnculata around pond margin; forest is pure Pinus contorta with 

understory of Juniperus communis. Moss polster; tundra vegetation with Pinus albicaulis parkland just 

below. 

Soil sample. Pinus albicaulis-Picea parkland, Abies rare. Surface muds from small (ephemeral?) pond; steppe with Sarcobatus 

vermiculatus, Artemisia tridentata, and abundant Bromus, 

Elymus, and other Gramineae. 

Surface muds from pond; pond surrounded by dense growth of 

Scirpus cf. acutus and other sedges, grasses, and rushes; upland 

steppe vegetation with Artemisia tridentata, Sarcobatus, 

Chrysothamnus, and numerous Gramineae. 

Surface muds from pond; open Populus tremuloides-Pseudotsuga 

forest; Shepherdia canadensis, Ceanothus velutinus, Juniperus 

virginiana, and Artemisia tridentata common in open areas. Mud from between rocks in depression; large open meadow with 

Carex, Gramineae, Pentaphylloides floribunda; Artemisia 

tridentata on higher unforested slopes below Pinus contorta forest. 

Surface muds from north end of lake; Nuphar, MyriophyUum, and 

Sparganium in lake; Vaccinium, Kalmia polifolia, Carex, and 

Gramineae along margin; Picea and Abies sparse near lake; 

Pinus contorta forest on upland. Moss polster from east side of lake; a few Picea, Abies, and Pinus 

albicaulis near lake; Gramineae-Artemisia tridentata steppe sur- rounding lake; mainly Pinus contorta forest on surrounding 

uplands. 

Surface muds from north edge of pond; large Carex utriculata fen 

surrounding lake; upland forest is Pinus contorta-Picea-Abieswith occasional Pinus albicaulis. 

Surface muds from shallow bay; Potamogeton alpinus and 

Sparganium in bay; few pond margin Carex; Picea-Abies-Pinus 

albicaulis-Pt"nus contorta forest. 

Silty surface sands. Picea-Abies-Pinus albicaulis-Pinus contorta forest. 

Surface muds from northwest shore of pond; Isoetes in pond; PiceaAbies-Pinus albicaulis forest. Juniperus communis and Ledum 

glandulosum in understory. 

Surface muds from north end of lake; Vaccinium, Carex, and 

PhyUodoce empetriformis on shore; Picea-Abies-Pinus albicaulis 

forest. 

Surface muds from southwest end of lake; Sparganium 

angustifolium, Persicaria amphibia, and /soetes in lake; Carex 

vesicaria and several Gramineae spp. around lake border; PiceaAbies on south and east sides of lake, Pinus contorta elsewhere. 

Surface muds from fen on north side of lake; Carex utriculata, 

Persicaria amphibia, Salix sp., and Vaccinium sp. in fen; 

surrounded by Pinus contorta forest. 

Surface muds from pond; Pinus contorta forest. 

Surface muds from pond; pond aquatics are Nuphar luteum, 

Sparganium angustifolium, Eleocharis macrostachya, and Carex 

spp.; forest is Pinus contorta with reproduction of Pinus flexilis(?). 

Surface muds from pond; parkland near upper edge of Picea-AbiesPinus albicaulis forest. 

Surface muds from pond; Picea-Abies-Pinus albicaulis parkland. 

flexilis and Pinus albicaulis. (See "Pollen and Seed 

Identification," p. E24). The latter two species are 

haploxylon pines with verrucae on the distal face of 

the pollen grain; the former species is diploxylon and 

has no verrucae (Ting, 1966, p. 7). Pollen of Pinus 

albicaulis type includes pollen of Pinus flexilis. Ecological considerations suggest that, of these two, Pinus 

flexilis pollen should prevail in the Artemisia steppe 
E18 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

and Pinus albicaulis pollen should dominate in higher 

vegetation associations, although no distinction 

between pollen of these pines is made here. 

SURFACE SAMPLE FROM 

PSEUDOTSUGA ASSOCIATION 

Pollen rain from one sample in an open Pseudotsuga 

forest cannot be distinguished from that in other 

forest types. Less than 1 percent Pseudotsuga pollen 

was found (fig. 13). Pseudotsuga is apparently a very 

small pollen producer; in other surface sample studies 

less than 5 percent Pseudotsuga pollen is usually 

found, even in Pseudotsuga stands (Bent and Wright, 

1963; Maher, 1963; Bright, 1966). Its pollen 

apparently ruptures easily; the grains found in this 

study were commonly broken. Small fragments cannot 

be identified; hence,counts of Pseudotsuga may be low 

partly because of poor preservation. No other pollen 

types diagnostic of this vegetation association were 

found. 

SURFACE SAMPLES IN 

PINUS CONTORTA FORESTS 

Pinus pollen makes up over 80 percent of the pollen 

rain in Pinus contorta forests, and nonarboreal pollen 

is low except in large meadows (fig. 13; table 2). Pinus 

contorta- type pollen is usually substantially more 

abundant than Pinus albicaulis type. Abies and Picea 

pollen range from 0 to 1 percent in pure Pinus contorta 

stands and from 1 to 4 percent where these species 

grow locally in mixed forests with Pinus contorta. 

Diversity of pollen types is least in this vegetation 

association. 

SURFACE SAMPLES FROM 

PICEA-ABIES-PINUS ALBICAULIS FORESTS 

Pinus pollen percentages are 80 and 85 percent, 

Picea is over 3.5 percent, and Abies is 1.5 percent in 

this forest association (fig. 13). Pinus albicaulis type 

pollen is several times as abundant as Pinus contorta 

type. 

Elevatton ( ft) EXPLANATION 

w 0 

Cicio o o o o 0 

~z8 8 8 8 8 ~ (f) LO(Or--CXJOl 

• P. contorta type 

o P. albicaulis type 

0 Pinus (individual bladders/2) 

SS-201- BASIN MARGIN 

SS-21 1--- Artemisia steppe 

,_ _________ PIATEAUFLANK _____ ~::------~c-+---------"'7 

SS-22 ~-- ___ !:_S!!_U.f!C!!~~~~~!!_a ____ _ 

SS-23 PLATEAU 

SS-25r----

SS-1 t---·-

SS-8 

SS-36~ 

SS-35 

SS-24f----

SS-16i--·--

SS-34 

Pinus contorta 

forest openings 

PLATEAU 

Pinus contorta 

closed forest 

f-------------------------

SS-25 PLATEAU 1---_.....-~ _ __,f'+--------<:...... 

SS-33 1-----

0 CM't-----

SS-121-----

SS-131-----

SS-14 f-----

Pinus contorta forest; 

local Picea and Abies 

f-------·------------------

SS -5 PLATEAU f-----j~-------t:t----------1 

SS-7 

SS-26 Pinus contorta-PiceaSS-27 Abies forest SS-28 f-----

f------------M-OUN'fAii\f SLOPES-- f-41>-----"f;-----++-------<... 

SS-29 Picea-Abies-Pinus 

SS-30 alb1caulis forest 

SS-2 f------------HIGH-PLAfEAUAND f-+.--€k---E~-----<:::::_ 

SS-39~ MOUNTAINS SS-38 Picea-Ab1es-Pinus 

SS-19 albicaulis parkland 

ss-9 --------------·-sl.iiViiViiTs ___ f--_.-4t-----e>--------;;; 

SS-18 Pi~~~:i:i~s;~~~~;-

0 20 40 60 80 1 Top of Uuckbean fen core 

1 00 0 1 0 0 1 0 0 1 0 0 1 0 

0 10 0 10 0 10 0 10 

PERCENT 

FIGURE 13.-Pollen from surface samples arranged by elevations and by vegetation types. Dashed line in sample SS -7 shows 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E19 

SURFACE SAMPLES FROM 

PICEA-ABIES-PINUS ALBICA ULIS 

PARKLANDS AND TUNDRA 

Insufficient data are available to distinguish 

high-levelPicea-Abies-Pinus albicaulis parklands from 

tundra, but together they can be distinguished from 

other associations by their pollen rain (figs. 13, 14). 

Parklands and tundra receive an average of about 70 

percent Pinus pollen in Yellowstone National Park. 

Samples from these associations differ from those in 

forests by having low but consistent values of 

Compositae (1- 3 percent) and Gramineae (4 -10 

percent), and they do not have the high Cheno-Ams or 

Sarcobatus of steppe samples. Occasional grains of 

plants common in alpine associations, such as Bistorta 

I 

Q) Q) 

"'"' 

.~ ~ -o..c 

O'"' c.C 

0 ~ c"' 

Q) E 

G<t: 

Q) 

!!! 

'iii 

0 

c. 

E 

0 

u 

Q) 

Ctl 

0 

~ 

:; 

Cl 

:.J 

a; 

!!! 

'iii 

0 

c. 

E 

0 

u 

Q) 

Ctl 

Q) 

u 

~ Q) 

c. 

> u 

Q) 

.s::: 

0 

and SelaginelliL densa, help to define alpine and 

subalpine parkland pollen rain. 

Maher (1963) found that in the San Juan Mountains, 

Colo., the Pinus pollen values are higher in alpine 

tundra than in Picea-Abies forests. Such is not the 

case in Yellowstone National Park samples. However, 

Pinus albicaulis is a common tree in Picea-Abies 

forests just below treeline in Yellowstone National 

Park; no ecologically analogous species is present in 

the San Juan Mountains. Also, my alpine sites are all 

from slightly above timberline. Samples from far 

above timberline might have higher Pinus percentages. 

Artemisia pollen percentages are also higher (up to 

18 percent) in subalpine and tundra areas than at 

lower elevations where A. tridentata grows (up to ·7 

~ 

448 

473 

296 

291 

334 

SELECTED RARE TYPES 

692 Arceuthobium 

339 

306 

328 Arceuthobium 

319 

309 

382 

334 

413 

321 Arceuthobium, Potentilla palustris 

333 Arceuthobium 

306 Arceuthobium 

376 Potentilla pa/ustris 

349 

396 

353 Arceuthobium 

341 Arceuthobium 

228 

339 

417 

431 cf. Phyllodoce 

344 cf. Phy/lodoce 

361 

526 Selagine/la densa 

601 Bistorta, Selagine/la densa 

317 Arceuthobium, Selaginella densa 

0 20 

0 

0 

20 

20 0 10 0 

0 10 0 10 

20 

0 

0 10 

25 

PERCENT 

the Pinus curve with Cyperaceae excluded from the pollen sum. Pine curves are cumulative. 
E20 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

percent) both in Yellowstone National Park and in the 

San Juan Mountains. Maher (1963) suggested that 

cirque lakes contain high values of Artemisia because 

the lakes remain frozen during the early flowering 

season. Pollen that falls on the ice is washed out 

during the melt season, and only pollen from lateflowering plants, such as Artemisia, is incorporated 

into the lake sediments. This process may explain the 

abundance of Artemisia pollen in high-elevation lakes 

in Yellowstone National Park. 

Whether the flowering season is important or not, 

the source of the Artemisia pollen in alpine surface 

samples is still a problem. Does the pollen come from 

local subalpine or alpine species or does it blow in from 

steppe vegetation surrounding the park? The alpine 

species arc small and produce less pollen than the 

larger steppe species. Pollen of other steppe species 

apparently were blown 10 - 20 miles laterally and 

4,000- 5,000 feet upward before deposition. 

The presence of Sarcobatus and 1 Cheno-Ams pollen 

in small amounts at some alpine sites (fig. 13) provides 

evidence that pollen from the steppe association does 

blow up to the tundra; these taxa grow abundantly in 

steppe areas but are absent from alpine areas. 

Compositae and Gramineae pollen in alpine sites may 

likewise blow up from their abundant steppe 

representatives, but plants in these families grow at 

all elevations in the park. Pinus and Picea certainly 

blow up from just below treeline, and in tundra areas 

where pollen production is low, relatively small 

amounts of pollen blowing in from afar could yield high 

pollen percentages. 

POLLEN RATIOS 

Ratios between two pollen types often show trends 

that are masked by other curves on the aggregate 

pollen diagram (Maher, 1963). A number of ratios 

were tested in the surface sample and fossil pollen 

diagrams, and two proved useful. Pinus albicaulis/ 

Pinus contort a ratios delimit Pice a-Abies-Pinus 

albicaulis forests from other forest types (fig. 14). The 

dominance of Pinus contorta over such large areas in 

the park makes this pollen ratio low (less than 1.3) 

except where Pinus albicaulis grows locally. At 

several sites preservation of pine pollen was not good 

enough to identify a large proportion of the grains as 

to species. Even with imperfect identification, 

however, most pine-pollen ratios were ecologically 

reasonable. The assumption that the two Pinus types 

are preserved equally well and are representative of 

the entire sample seems valid. 

Gramineae!Pinus ratios distinguish forested from 

nonforested areas (fig. 14). These ratios are high 

(about 0.050- 0.209) in the steppe and alpine 

vegetation associations and in large forests openings; 

they are low (less than 0.025) in forested areas (fig. 14; 

table 2). 

Pice a/ Pinus ratios that were used successfully by 

Maher (1963) as an indication of subalpine vegetation 

show no meaningful trends in Yellowstone National 

Park surface samples, probably because of pollen 

production of Pinus albicaulis in the subalpine 

vegetation of the park. Lack of an ecologically 

analogous pine in the San Juan Mountains makes the 

Pice a/ Pinus ratio a more effective indicator of 

subalpine vegetation. 

QUATERNARY PALYNOLOGY 

MATERIALS AND PROCEDURES 

The cores were taken with a modified 2-inch 

Livingstone piston sampler (Wright and others, 1965) 

in early October 1966 and early September 1967. Long 

cores were taken from Buckbean fen and Lilypad pond 

(fig. 7), and shorter cores were extracted from Trail 

Creek pond. When core length was less than 

penetration, it was arbitrarily assumed for labeling 

purposes that the basal segment of each drive was 

missing. The cores were wrapped in the field in saran 

and heavy -duty aluminum foil, sealed with masking 

tape, and stored in a refrigerator. Reported here are 

pollen and macrofossil analyses from the 10-m core 

taken in Buckbean fen and macrofossil analyses from 

the basal 2 m of the core taken in Lilypad pond. For 

Buckbean fen, pollen samples were taken at about 

10-cm (centimetres) intervals in the basal2 m and at 

about 20-cm intervals in the remainder of the core. 

These samples received the same chemical treatment 

as the surface samples. 

Plant macrofossils were prepared by soaking a 

50-ml (millilitre) sample of sediment for as long as 2 

days in very weak (less than 5 percent) KOH. The 

sample was then washed through 32- and 140-mesh 

(0.5 and 1.0 mm) screens with a shower nozzle. 

Macrofossils were picked from the washed samples 

with a small brush and stored in glycerin. 

The pollen was identified by comparison with the 

reference collection at the U.S. Geological Survey, 

Denver, Colo. The collection is large but is incomplete 

for Rocky Mountain species. Macrofossils were 

identified by comparison with the seed collection at 

the University of Colorado Herbarium. The collection 

is small and is fairly complete only for taxa encountered as fossils. 

The certainty of identification of pollen and 

macrofossils is indicated by the use of "type" and "cf." 
VEGETATION HISTORY, OF THE YELLOWSTONE LAKE BASIN 

GRAMINEAE/P/NUS POLLEN RATIO SAMPLE NO. 

Steppe SS-20~--~----0~.0_5 ____ ~ ___ 0~.1----~--~~--~----0~·=2----~--~----~--~ 

SS-21 

Pseudotsuga savanna SS-22 

SS-23 

Pinus contorta SS-25 

forest openings SS-1 

SS-8 

SS-36 

Pinus contorta 

closed forest 

SS-16 

SS-34 

SS-25 

SS-33 

Pinus contorta forest; OCM 

local Picea and Abies SS-12 

SS-13 

SS-14 

SS-5 

Pinus contorta- SS-7 

Picea-Abies SS-26 

forest 

SS-27 

SS-28 

Picea-Abies-Pinus SS-29 

a/bicau/is forest SS-30 

SS-2 

Picea-Abies-Pinus SS-39 

albicaulis parkland SS-38 

SS-19 

Picea-Abies-Pinus SS-9 

albicaulis tundra SS-18 0 

> 

I ..... _ 

Gramineae/ Pinus 

---------------.., 

/ ,_ 

/ 

/ 

/ 

-------> 

-----

5 

========--

11 

P. ALB/CAUL/SIP. CONTORTA POLLEN RATIO 

FIGURE 14.-Ratios for surface pollen samples. 

12 

E21 
E22 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

If the name of a taxon is followed by "type," the 

specimen matches not only that taxon but also others, 

and the name is selected for ecological or geographical 

reasons. The use of "cf." (=confere) means that 

identification is uncertain because of poor preservation, inadequate reference materials, or ill-defined 

morphology (Watts and Winter, 1966). 

Relative pollen frequencies were determined with 

few exceptions from counts of at least 300 

grains/slide. The slides used in this study are stored 

in the University of Colorado Museum. Percentage 

curves in the pollen diagram (fig. 15) are based on a 

pollen sum of total pollen excluding spores and 

aquatic-plant pollen. 

The Pinus pollen curve is a cumulative plot of four 

curves (fig. 15). Pinus albicaulis type is plotted at the 

base of the total pine curve. Above that curve is 

plotted Pinus contorta type. The next higher curve 

compresses individual bladders (treated as half grains) 

of Pinus pollen (times 1

/2, that is, two half pines are 

counted as one pine); the top curve comprises whole 

Pinus grains that could not be differentiated as to 

ZONE SUBZONE 

Picea -

AbiesPinus 

contorta 

Pinus 

contorta 

Pinus 

contorta 

Pinus 

contorta -

Pinus 

albicaulis 

Picea -

Juniperus- Populus 

Pinus 

a!bicaulis 

Betula 

SAMPLE NO. 

SEDI -

Ol 

c 

] Q) 

u ro X ~ ~ u 

~ ~ ~ .s .s ~ Q. Q. > 

AND 

CARBON-14 

DATE 

(years B.P.) 

MENT DEPTH '-;;; 'iii u 

0 0 

W-2280 I Peat 

2,470 .t 250 l 

Pea t 

9 240 W-2284 + 300 < 0 1 5 • rgan1c 

mud 

. . . . . ' ..... .. . - 6 

:\ 

\ 

1- 1-

\ 

-~)_ ·. 

1 

..... ~~~ .. \. 

,\ > 

l)p /) 

I( j \: L~C ... ... . \ ~ •v 

~ 

~ I ...,::: <._ 

W-2285 

11 ,550 :!: 350 

OrganiC 

mud 

~ :0 / 

7 - / <.: 3[ (~, . I 

Sandy 

slit 

8 

Sandyj 9 

slit 

... ::-.., ... ··· ······· 

~ ,~ f J ~ L 1 ·s~:r .. ~ ~ "~ ~ ') ' ;> f' ''' 'f '1 '1 r' '' I r l - 'I' r• r r, I' I' I' 

0 1 0 20 30 40 50 60 70 80 90 5 5 5 5 5 5 5 5 5 

PERCENT 

5 5 5 5 5 5 5 5 0 10 20 30 5 5 

FIGURE 15.-
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E23 

species. A separate total Pinus pollen curve is plotted 

for the upper 400 em of the core. This curve excludes 

Cyperaceae pollen from the pollen sum because of its 

local origin. 

The pollen diagram (fig. 15) is divided into two 

pollen assemblage zones (hereafter simply called 

zones). The zones are biostratigraphic units called 

assemblage zones as defined by the American 

<li 

Q. 

~ 

<li <li ~ "' "' ~ 0 0 § ~ ~ -~ ::J 

~ "' tl ~ Q 

:J -~ <li 

f- l:J "' ~ <li t:: Q) u 

<li 

<li ~ ~ Q. 

<li <li ..')1 <li Q. ~ "' <li -'? ~ "' "' <li ~ Q. ~ -'? "' "' e: -Q ~ "' Q) Q) <li <li .')1 ~ t:: ~ Q) 

~ "' "' ~ Q ~ ·~ :5 :5 u t: "' u t:: i3 t:: 

"' ~ -~ ~ 

Q Q. Q) "' Q) Q 

Q. "' Q. 

~ 0 u Qi 

~ "' Q ~ 

E E Q) 

~ t:: 2 "' .0 en ·g .g "" "' ~ ~ Q. "' ::,.. 

~ "' -~ ~ 0 0 > ~ 0 " -~ Q 0 E ~ e; Q) c u u u u Q: ~ a CXl ::) ~ "' Q_ u a:: ::J _J 0 "1: Q_ Q_ 

I 

-~ -

I 

-I-f-~ t--- -t--t-- ·- t---

I 

-I- -I- - 1-- --L- -t--- 1--1- t---

~ - -'--- L -- . ..... . . ! . . 

t---

~--1---- - .... --- I· - ·- ---

-1-- - I- 1--!--

I·· .. . . . .. ... ... . . . . 

t • ~ 

• • • ~ 

I ~ 

t 

~ c 

<li 

<li 

"0 

§ 

Q) 

"' Q) 

u 

"' c 

0 

en 

> 

~ 

. 

Commission on Stratigraphic Nomenclature (1961). 

The zones are defined by their fossil content and 

position in the core. The name of each zone carries 

implications about the ecological conditions at the time 

of deposition. Similar zones appear in the core from 

Cub Creek pond (Waddington and Wright, 1970) and 

other cores (R. G. Baker, unpub. data). This regional 

similarity of zones implies that vegetation changes 

NOT INCLUDED IN POLLEN SUM 

(f) ,--

z 

~ a:: 

l? 

z ~ w 

_J ~ 

_J 

~ 0 CL ~ <li 

"' ·s .')1 a:: Q) :2 w <li u 

"' ~ ·s a:J Q. 

2 ~ .')1 ~ "' ·~ Cii t:: 

ill ::J :2 "' ..'? ] ..')1 Q. ~ 2 

i3 z ·;::; ..'? ~ Q. "' ~ ..')1 -'? ~ 

-~ "" ~ t:: _J t:: '- ..')1 -!::: 

g .§ Q Q 

l:J ~ <i ~ "' "' ~ "' f- -!::: -!::: ~ ~ (f) Q_ ~ a; §- ~ ~ Q 0 "' ~ a- Q 'G 'G Q_ ~ f- < h 'G ~ Q_ 

g 

"' X 

"' 

321 

I r 382 

874 

• I I 256 I 316 

- 453 - I -- -- -

384 I 

196 

~ ~ 300 

357 

J- - 336 - -f--

359 

309 

:i31 

282 I ~ 1- ·-'----- ·262 I 

303 : 

I 357 I 

360 I 

I 304 I 

I. 350 --·304 · • • 0 . . . .. 

351 I 

~ t 305 

287 

~~~ 

335 ~ 337 

.I.- . 354 

~ ... . -·- - 375 I 

384 

336 

~ 323 

320 

345 

451 t 

504 

427 . .. .. •• •356 . .......... .... 286 

t--- -

l Ui ~ • r6 15 

.. :if3 " -- .... . . 

478 

~~~ - -t--- J 191 

~ "0 

"0 

E 

0 

11 

"0 

:2 

c 

~ 

~ 

r 

I 

. . . . 

... 

. .. 

~ 

"' en 

Q) 

"' c 

"0 

~ c 

• 

• 

~ I I 412 ~1 

'-, '-, i-t l'l I' -, I'-, -, -,1'1';-'1' r ~ -, I I I I I' ..., I' I' I' I' I' I' 262 I' I "r -,I' rr<l'l' '-, r--.1 I I I' 5 5 50 10 0 10 20 30 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 10 20 30 

PERCENT 

Pollen from Buckbean fen core. 
E24 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

were similar throughout the region. The zonation of 

the diagram is summarized in table 3, and the pollen 

counts for Buckbean fen are listed in table 4. 

SELAGINELLACEAE 

Trilete spores in the lower part of the Buckbean fen 

core match Selaginella dens a perfectly (pl. 1), and this 

is the only species reported in the modern park flora 

(McDougall and Baggley, 1956). It is most common 

above timberline. Two other species occur in eastern 

Wyoming (Porter, 1962). Another species, S. selaginoides, occurs at middle elevations in western 

Wyoming, but its spores can be distinguished from 

those of S. densa on morphologic grounds. 

The time and stratigraphic relationship between the 

assemblage zones, the C 14 dates, and the glacial 

periods is shown in figure 16. 

POLLEN AND SEED IDENTIFICATION 

PINACEAE 

Pollen and spores were identified using the 

reference collection of the U.S. Geological Survey, 

Denver, Colo. Plant macrofossils were identified by 

comparison with a collection that I assembled from 

the University of Colorado Herbarium. On plates 

5- 10, the COLO numbers are the University of 

Colorado Herbarium numbers of voucher specimens 

for reference seeds, needles, and bracts. RGB 

numbers are my own collection. Some of the criteria 

for identification are discussed here so that the pollen 

and macrofossil taxa can be better evaluated. 

A few grains were found that match Pseudotsuga 

menziesii (pl. 1). Larix occidentalis Nutt. 

and Larix lyallii Pari. have similar but smaller grains, 

and these trees now grow from central Idaho 

westward (Bright, 1966). Pseudotsuga grows locally in 

Yellowstone National Park. I have, therefore, 

identified the pollen as Pseudotsuga. One needle of 

Pseudotsuga was found (pl. 5). 

(/) 

w 

a: 

fw 

~ 

~ 

Ifa... 

w 

0 

w 

a: 

0 

u 

0-r~-~~~\t~~~~----------------------------------------------------------------------------~ // 

-

-

2 -

-

3 -

4 -

-

5 -

-

6 -

7 -

-

Q.l 

c 

0 

N 

!S 

... 

2 

c:: 

0 

u 

"' :;:, 

c:: 

~ 

Picea-AbiesPinus contorta 

subzone 

~---.--------------------------------------~-~ 

~?--+---------? ----------------~--~lfl~ I 

STRATIGRAPHIC ZONE. OF HIATUS I 

/ / 

/ 

/ / / 

~ 

/ 

/ 

Pinus contorta J-i- I 

subrone ( I EXPLANATION 

r-------___.____-----1)-• 

/ 

/ 

/ 

/ 

Pinus albicaulisPinus con tort a 

subzone 

/ I [!] Core 

// I + - Vertical dimension shows interval 

~ TIME MAGNITUDE of core 

~ OF 

1

1 Horizontal dimension shows age of 

r1 APPARENT C' 4- dated sample with error 

8 _ ~ ~ /Lr.. HIATUS I [•] Extrapolated age 

~ 2 Populus / 1 

- Cl. "' subzone / 1 

9- ~ ] Betula /---r' I 

2 ~ subzo[.{ i- 1 

10~ -·~--------~~----~----_L ____ _L ______________ i_~~----------------------~ 

PINEDALE GLACIATION 

I I I I I 

14 13 12 11 10 

AL TITHERMAL I 

+ I I I I I 

9 8 7 6 5 

AGE, IN THOUSANDS OF YEARS B.P. 

I 

4 

NEOGLACIATION 

I 

3 

I 

2 

I 

FIGURE 16.-Relationships between assemblage zones, carbon-14 and extrapolated ages, and time-stratigraphic boundaries. 

0 
TABLE 3.-Summary of inferred changes in environment at Buckbeanfen during the last 12,000+ years 

Core 

c14 date 

Pollen (interpolated Subzone depth dates in Terrestrial plant community zone (em) brackets) 

Pinus Picea-Abies· 240} 2,470:!:250 Mixed Picea engelmannii, contorta Pinus contorta 260 Abies lasiocarpa, Pinus contorta forest. 

Sparse Pseudotsuga 

menziesii. 

[2,800) 

420 [5,000) 

Pinus contorta 440} 460 5,390:!250 Closed· Pinus contorta forest 

UNCONFORMITY(?) 

. 500} 

540 9,240:!:300 

600 [10,160) 

Pinus contorta· Pinus albicaulis 

700} 11,550~50 724 2 770 11,630:!:180 

Picea-Juniperus· Populus 

Pinus albicaulis 

875 

Betula 

960 2 14,36Ch400 

lThe 15-ft lagoon, Buckbean fen, dried up during this time. 

2oate by correlation with Cub Creek pond. 

Open Pinus albicaulis-Pinus contorta forest with Picea, 

Abies and Pseudotsuga rare. 

Picea engelmannii-Abies 

lasiocarpa-Pinus albicaulis 

garkland, with Populus 

alsamifera and Juniperus 

communis. 

Tundra(?) but with subalpine 

herbs, Juniperus communis 

and Betula glandul osa. Occasional Picea or 

Pinus albicaulis may be 

present nearby. 

Aquatic and semiaquatic Inferred Water Lake level Glacial advance or plant community climate depth at above present glacial retreat coring level 

site (ft) 

Fen v:J.etation with Carex Slightly 0 Present level ...... Gannett Peak Stade, 

dia ra, C. utricu/ata. C. cooler and Neoglaciation. 

vesicaria, C. limosa, moister. 

Potentilla palustris, and 

Menyanthes trifolin.ta. 

Small, shallow pond with 0 10 ft to present Temple Lake Stade, 

Nuphar; fen with Carex level. Neoglaciation. 

diandra and C. utricu/ata, 

encroaching into pond. 

Shallow-water a~uatic Maximum 1 0-35 10·, 15·, 25·, and Altithermal. 

vegetation wit Nuphar warmth and 40-ft levels. luteum, MyriophyUum sp., dryness. 

Naias flexilis, and 

Potamogeton gramineus. 

Aquatic and shoreline Warm 45-65 60-ft level(?) ....... Late stade, Pinedale 

macrofossils rare. t Glaciation. 

dry cool, 

t 

warm 

Aquatic and shoreline Cool, moist. 70-100 90-ft level(?) ....... Middle stade, Pine· 

macrofossils rare. dale Glaciation. 

Pioneer aquatics Cold, moist. 90--or 110-ft level Middle stade, PinePotamogeton fi/iformis dale Glaciation. 

and Potamogeton alpinus. 

< M 

c;") 

M 

~ 

> 

~ 1-4 

0 

z 

::r: 

1-4 

r:.n 

~ 

0 

~ 

~ 

0 

"'%j 

~ 

::r: 

M 

~ 

M 

t'-1 

t'-1 

0 

~ r:.n 

~ 

0 

z 

M 

t'-1 

> 

~ 

M 

to 

> r:.n 

1-4 

z 

t_:l:j 

~ 

01 
E26 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

TABLE 4.-Pollen counts for Buckbean fen, 

<1> ' <1> <1> <1> 0.. Cll ~ 

0.. ~ <1> <1> $ 0.. $ Cll <1>"' 0.. <1> <1> "C $ <:::! "'~ .. ~ .. ~ 

~~ 0, "' ~ 0.. ~.c $ Cll ... <1> ... "' ~ <:::! i; ;:! $ ~ Cll .... ~ ~ 0 ~ 0 ;:! "C~ 

~ ~ <:::! -~ -g; -~ -~ § -~§ 

·= ~ c-z ;:! 1:: 0 ::I c <:::! c "' ~ ~""' e·~ i: -~ o.."' ~ ..c c 8...6 0 ::I .,] ~§ '"t::l .s ~ <..> <1> 

~t ~~ ] ~ 0 ~ .c ~ ~ <:::! .; ;:! l1 .e. 1 l: "' co.. s:: E c 1- O..bO .... E "'<; 

-~~ ~ ~ ~ (::! ~ ] t~ -c:!C -c:!";; ~ ll<t: l: ..c E ::::~ e·- fr'-' 0 (::!~ (::! <..> d: ..c 

~ 1:: ~ oE-< 0...::1 

~ ~ ~ 

~ .:; & ~- ~ <:::! 

0 E-o ~ c.. ~ ~ ~ \..) kl ~ u ~ ~ u u 

0 230 129 4 97 5 1 0 0 0 0 0 1 0 2 2 0 0 28 3 1 1 1 0 

20 241 223 8 10 3 8 3 0 0 1 0 0 1 0 0 0 0 31 13 3 2 1 0 

40 748 644 19 85 5 6 0 0 0 4 0 0 1 0 0 0 0 62 10 6 0 4 0 

60 200 161 4 35 2 4 0 3 0 0 0 2 0 0 0 0 0 22 7 0 1 2 0 

80 262 221 16 25 6 1 0 0 2 0 0 0 0 0 0 0 1 26 5 0 1 1 0 

105 357 275 10 72 8 5 0 0 1 1 0 0 1 1 0 0 0 30 9 1 0 8 1 

125 278 272 2 4 6 2 1 0 1 1 0 0 0 0 0 0 0 30 7 1 0 4 0 

140 143 86 5 52 2 3 0 0 0 0 0 0 0 0 0 0 0 7 3 0 0 1 0 

160 211 147 17 47 7 2 0 0 1 1 0 0 1 0 0 0 0 11 2 6 1 2 0 

180 253 223 10 20 7 6 0 0 0 2 0 1 0 0 2 0 0 29 4 2 0 3 0 200 246 155 8 83 8 6 0 0 0 0 0 0 0 0 0 4 0 17 5 2 1 4 0 220 181 118 8 55 5 0 2 0 1 2 0 0 0 0 0 0 0 16 4 1 1 2 0 240 223 187 10 26 2 0 0 0 0 0 0 0 1 0 0 0 1 24 3 1 0 5 0 260 228 152 12 64 10 0 0 0 1 7 0 0 0 0 0 0 0 21 2 1 1 3 0 280 241 219 6 16 1 0 0 0 1 0 0 2 0 0 0 0 0 22 3 0 0 1 0 300 211 176 15 20 0 1 0 1 0 0 0 1 0 0 0 0 0 33 6 0 0 2 0 320 238 227 3 8 3 2 2 0 1 2 0 1 0 0 1 0 0 33 3 3 0 2 0 340 280 243 10 27 6 4 0 0 0 4 0 2 0 1 0 1 0 23 9 1 2 4 0 360 231 195 20 16 4 5 0 0 0 3 0 0 0 0 0 0 0 22 7 2 0 1 0 380 260 237 10 13 5 2 2 0 1 1 0 1 0 0 0 0 0 15 8 0 2 2 0 405 272 229 3 40 7 3 2 0 0 0 0 2 2 0 0 1 0 30 11 2 1 2 0 420 249 221 12 16 2 2 0 0 0 1 0 0 1 0 0 0 1 33 7 2 2 0 0 

440 282 271 5 6 2 3 1 0 0 1 0 0 1 0 1 0 0 38 6 2 1 2 0 460 220 209 4 7 0 1 0 0 3 4 0 1 3 0 0 0 0 34 14 4 1 3 0 480 235 224 2 9 0 1 0 0 1 1 0 0 1 0 0 0 0 31 4 3 2 3 0 505 208 188 3 17 1 0 0 1 2 0 0 0 0 0 0 1 0 37 21 5 1 4 0 515 697 610 13 74 1 2 1 1 2 0 1 3 0 2 0 0 0 126 29 7 8 5 1 525 271 244 8 19 1 2 0 0 2 3 1 0 1 0 0 0 0 34 12 3 2 2 0 550 248 231 9 8 0 2 2 0 3 2 0 0 1 0 0 0 1 54 9 4 3 1 0 580 241 217 9 15 0 1 1 4 2 1 0 0 0 0 0 0 0 50 11 4 8 2 0 600 265 243 14 8 0 2 0 1 3 4 0 0 1 0 0 0 0 43 10 3 5 5 0 

620 243 188 26 29 3 1 0 0 8 2 0 0 1 2 0 0 0 63 27 4 5 4 0 

640 266 195 58 13 2 0 0 1 4 4 0 1 0 1 0 0 1 59 19 1 3 2 0 

660 207 192 12 3 2 1 1 1 2 3 0 0 0 0 0 0 1 65 22 6 3 3 0 680 236 208 25 3 3 1 1 2 0 10 0 0 0 0 1 0 0 39 12 3 3 1 0 700 203 163 27 13 1 0 5 1 3 2 1 1 0 0 0 0 0 56 13 4 6 2 0 

720 227 200 17 10 0 2 2 0 3 4 0 0 0 0 0 0 0 76 10 3 3 5 0 730 277 234 13 30 3 2 1 0 5 12 0 0 0 0 0 0 0 105 14 8 5 4 0 750 361 282 20 59 6 4 0 2 4 2 0 0 1 1 0 0 1 78 17 6 6 1 0 760 294 250 24 20 1 3 0 2 2 2 2 2 1 0 0 0 0 80 17 2 4 3 0 770 249 150 76 23 1 3 0 0 0 2 2 2 0 0 0 0 0 48 17 5 0 8 0 

782 172 107 34 31 1 6 0 1 1 6 5 0 0 0 0 0 0 61 12 3 2 4 0 

801 182 121 42 19 3 5 0 0 4 6 0 0 0 0 0 0 3 97 15 6 10 3 1 

810 279 172 58 49 13 5 0 4 7 1 10 3 2 0 0 1 0 161 35 6 8 9 0 

820 175 86 75 14 12 7 2 2 9 19 5 0 0 0 0 0 1 122 26 11 8 4 0 

830 179 99 53 27 14 3 1 0 6 0 1 3 2 0 0 0 0 113 18 6 4 7 0 

842 79 34 30 15 7 4 0 0 6 7 16 0 0 0 0 1 0 41 13 4 0 2 1 

850 149 89 53 7 11 14 0 2 2 16 8 0 1 0 0 0 0 121 9 4 7 5 0 

860 83 61 14 8 6 1 0 0 3 13 9 0 1 0 0 1 0 67 7 1 9 4 0 870 136 71 59 6 17 6 0 5 6 7 3 0 0 0 0 0 0 102 20 13 5 4 1 

880 167 113 51 3 11 6 0 3 5 15 4 0 2 0 0 0 0 69 5 0 7 3 0 

890 186 101 82 3 5 11 0 6 9 33 5 1 1 0 1 0 0 106 18 9 1 6 0 

900 157 86 65 6 16 12 0 6 10 20 4 1 0 0 0 0 0 97 23 8 2 5 0 

910 101 60 38 3 14 4 0 14 13 21 1 0 2 0 1 1 1 103 21 7 4 9 0 

920 144 98 39 7 10 5 0 3 5 15 3 0 1 0 0 0 0 85 16 5 1 10 2 

930 233 129 87 17 24 5 0 3 9 19 4 0 3 0 0 0 0 135 24 7 2 14 2 

943 160 108 47 5 11 10 0 15 7 16 9 0 0 0 0 1 0 97 18 3 4 6 2 

953 98 64 32 2 10 2 0 4 1 6 0 0 0 0 0 0 0 36 9 2 3 3 0 

958 109 67 38 4 5 3 0 2 3 7 0 1 0 0 0 0 0 75 18 9 3 4 1 

Juniperus pollen is common at the bottom of the grows abundantly on the plateau. The only fir that 

core (pl. 1). Species of Juniperus cannot be dis- grows in the park is Abies lasiocarpa. Needles of Picea 

tinguished by their pollen, but needles and a twig of engelmanii have been identified (pl. 5). Probably all 

Juniperus communis are identified from two levels (pl. the spruce and fir pollen belongs to these two species. 

5). Juniperus communis is the only juniper that grows Pine pollen (pl. 1) was grouped into haploxylon 

from low elevations below the plateau up to and above (with distal verrucae) and diploxylon (without distal 

timberline. Juniperus virginiana L. var. scopulorum verrucae) (Ting, 1966). Two haploxylon pines, Pinus 

Lemmon grows only at low elevations around flexilis and Pinus albicaulis, occur in the park 

Mammoth and in other areas. I believe most of the (McDougall and Baggley, 1956). Pinus flexilis grows 

Juniperus pollen to be Juniperus communis. only at low elevations around the margins of the 

Picea pollen (pl. 1) was not differentiated as to plateau. Pinus albicaulis grows mostly up near 

species, but Picea engelmannii is the only spruce that timberline but also on rocky cliffs and ledges at lower 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E27 

given in numbers of poUen or spores in tallies 

<I> 

t.s 

1'1 1'1 <I> "0 <I> 

~ !:! t.s <I> .... 1'1 l'l ., ·= :S ~ ~ 1'1 c t.s <I> 

~ .0 ·2 !S ;g ·~ c: 

<I> t.s 

·= ;;:. ;g "" Ill t.s ~ c t.s <I> <I> 0 

~~ ·~ 0 !:! ..c: ~ < < "' :a ;... c.> t.s 1- Ill<::! :t 0 ..c: 

.~ c ~ H -<I> 0 Q. 

~ ~ ~ ~ ~~ <::! ~? R. 0 .:: ~ 0 ~ Ill "§ Ill 8o. 1'1 0 < ·~ 1'1 Q. Q. c <I> ... <I> 1'1 ~ ~ Ill <::! 0 ]'Ill -" <I> <I> -;... ~ c ~ .':;2_ R. 

~.s ;... c "<::! "0 ..c: t.s Q. 

~ ·~ .... 0 ~ ~ ~ ~ 0 Ill"<:! ~ c: c: 

~ ] 0 ;... 

~ t.s ~ ;:J ;:J u Q:l u 0:: ~ Cl.. Ill V) 

2 29 0 0 0 0 2 0 4 7 2 0 0 0 2 20 0 1 5 9 7 0 9 66 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 2 1 0 12 15 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 14 1 0 0 

2 3 0 0 0 0 0 0 0 1 2 0 0 0 0 0 0 0 2 1 3 Menyanthes 7. 

7 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 4 0 1 0 5 24 0 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 3 0 0 Caprifoliaceae 1, Equisetum 1. 

8 45 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 4 1 1 0 

2 30 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 18 2 1 0 

3 50 0 0 0 0 0 0 1 0 0 0 0 0 0 4 0 0 25 0 0 Polygonum ramosissimum type 1. 

10 37 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 7 1 0 0 8 34 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 9 2 5 0 

2 142 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 1 0 10 36 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 7 3 0 Tsuga 1. 5 50 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 16 3 0 Eriogonum 1, Menyanthes 1. 

5 5 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 1 2 3 0 4 3 0 0 0 0 0 0 0 0 4 0 0 0 0 1 0 4 7 0 0 0 

5 ~ 6 0 0 0 0 0 0 1 0 12 0 0 0 0 0 0 3 5 0 0 0 

6 9 0 0 0 0 0 0 2 2 8 0 0 0 0 1 0 3 5 3 2 cf. Ceanothus velutinus 1. 

5 14 0 0 0 0 0 0 1 0 4 0 0 0 0 2 0 2 9 0 1 Sparganium 1. 

3 1 0 0 0 0 0 0 1 0 7 0 0 0 0 0 0 0 4 6 0 0 

2 6 0 0 0 0 0 0 6 0 0 0 0 0 0 2 0 2 2 5 2 Juglans 1. 0 3 0 0 0 0 0 0 1 0 3 0 0 0 0 1 0 16 2 0 0 0 

8 3 0 0 0 0 0 0 0 0 2 0 1 0 0 0 0 3 11 1 0 0 

6 7 0 0 0 0 0 0 3 0 1 0 2 0 0 1 0 30 2 2 0 Eriogonum 1. 

3 2 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 6 3 1 0 0 

3 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 2 0 2 4 0 

14 3 0 0 0 0 0 0 2 0 0 0 0 1 0 0 0 54 15 0 3 0 

0 4 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 50 3 0 1 0 

3 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 18 4 0 1 Onagraceae 1. 

5 5 0 0 0 0 0 0 2 0 0 0 0 1 0 0 0 29 3 1 3 0 

7 4 0 0 0 0 0 0 1 0 0 0 1 0 0 3 0 39 3 0 0 0 

4 7 0 0 0 0 0 0 2 0 0 0 0 3 0 3 0 26 5 1 1 Polygonum 1. 10 2 0 0 0 0 2 0 1 0 0 1 0 1 1 1 0 21 2 0 1 Cruciferae 1, Umbelliferae 1. 6 7 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 25 6 0 1 0 

6 3 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 47 6 1 1 0 

10 3 0 0 0 0 0 0 8 0 0 0 0 0 0 1 0 21 1 0 0 0 10 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 23 10 2 2 0 

13 2 0 0 0 0 0 0 1 0 0 0 0 0 0 4 0 16 12 2 5 Acer negundo 1. 9 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 13 6 0 0 Polygonum ramosissimum 1 Eriogonum 1. 8 4 0 0 0 0 0 0 0 0 0 2 0 0 1 1 0 4 3 0 2 0 9 6 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 11 5 0 0 cf. Pedicularis 2. 

8 3 0 0 0 1 0 0 0 0 0 0 0 0 0 4 0 11 7 3 3 Leguminosae 1, Equisetum 1. 

11 8 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 15 7 3 0 Sparganium 1. 

32 7 0 0 1 3 0 0 0 0 0 0 0 0 1 0 0 21 0 15 14 Sparganium 1, Acer3, cf. Scrophulariaceae 1. 

17 14 5 0 0 0 0 0 0 0 0 0 0 3 0 4 2 34 4 0 0 Fraxinus 1. 

19 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 13 11 ·0 10 0 

18 1 0 0 1 0 0 0 1 0 0 0 0 0 0 3 0 6 5 2 1 0 

12 11 0 0 0 0 0 1 0 0 0 0 0 2 0 4 0 17 6 2 5 Eriogonum 1, Oxyria 1, Koenigia 1. 

8 2 0 0 0 0 0 0 0 0 0 0 0 2 0 2 1 7 3 2 4 0 

29 8 2 0 0 0 2 0 0 0 0 0 0 1 0 4 0 23 12 1 2 0 

20 3 0 0 0 0 0 0 0 0 0 0 0 3 0 3 1 47 7 2 11 Erigonum3. 45 19 7 0 0 0 0 0 0 0 0 0 0 1 0 8 0 21 13 3 18 Urtica 3, Eriogonum 3. 

28 15 0 1 0 1 1 0 0 0 0 0 0 0 0 4 0 37 17 5 11 Polygonum persicaria 1. 

34 12 2 0 0 0 0 1 0 0 0 0 0 1 0 5 1 29 14 6 9 Polygonum ramosissimum type 1, Plantago 1. 

15 7 4 0 0 0 0 0 0 0 0 0 0 0 0 1 1 32 13 0 3 Sparganium 4. 

31 19 5 0 0 0 0 0 0 0 0 1 0 1 0 1 2 29 15 9 10 Umbelliferae 1, Leguminosae 1. 31 12 6 0 1 0 2 1 0 0 0 1 0 1 2 3 3 51 17 6 21 0 

9 6 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 75 5 0 3 Eriogonum 1. 

11 10 0 0 0 0 1 0 0 0 0 0 0 1 1 2 0 85 4 5 2 0 

elevations on the plateau. Haploxylon pine needles are A few grains of Tsuga were found in the core (pl. 1). 

fairly common in the cores (pl. 5), but no morpho- Both T. mertensiana and T. heterophylla are 

logical criteria have been found to distinguish Pinus represented. A Tsuga grain also was found in the 

flexilis from Pinus albicaulis needles. In fact, the living surface samples, and all grains are attributed to 

trees are distinguished only by difference in cone long-distance transport. Both species have mainly a 

length. Considering present distribution, the pollen west coast distribution, though both extend inland to 

and needles are referred to Pinus albicaulis type, and northern Idaho. 

they almost certainly represent this species. BETULACEAE 

The only diploxylon pine that grows in or near the Betula pollen grains are most abundant near the 

park is Pinus contorta. Pinus ponderosa is absent from bottom of the Picea-Abies-Pinus albicaulis zone in 

northwest Wyoming. Needles are identified with Buckbean fen. They are even more abundant in this 

certainty as Pinus contorta (pl. 5). zone at Cub Creek pond (Waddington and Wright, 
E28 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

1974). No Betula macrofossils were found in Buckbean 

fen core, but in the equivalent zone of the Lilypad 

pond core Betula glandulosa seeds and catkin scales 

are common (pl. 6). Betula occidentalis, the only other 

birch that occurs in northwestern Wyoming, is found 

at lower elevations. The pollen of the birch peak, 

therefore, is attributed to B. glandulosa. 

Alnus pollen, which occurs sparsely but continuously in the P't'nus contorta subzone of the Pinus 

contorta zone, probably represents Alnus tenuifolia. It 

is the only species that occurs in Wyoming today, and 

one fruit of Alnus tenuijolia was found (pl. 6). The 

fruits are wingless and cannot be confused with other 

species of western alder or birch. 

COMPOSITAE 

A single Compositae seed was found in the Lilypad 

pond core. It may be identifiable to species, but the 

reference collection for the large family has not been 

completed. Compositae pollen was separated into 

Ambrosia type (pl. 2), Artemisia, subfamily 

Tubuliflorae, and subfamily Liguliflorae (pl. 2). 

.Ambrosia type probably includes pollen of Franseria, 

a western plant of semiarid regions. 

CRASSULACEAE 

The Sedum seed is referred to S. rhodanthum. S. 

rosea has similar seeds, but a delicate epidermal 

reticulum and black tip seem to be absent on seeds of 

S. rosea. S. rhodanthum now grows on the margins of 

the fen surface. 

CRUCIFERAE 

Seeds of Rorippa occur in both Lilypad pond and 

Buckbean fen (pl. 10). They match R. islandica but 

cannot be distinguished on the basis of our reference 

material from other Rocky Mountain Rorippa species. 

One seed of Descurainia californica was found in the 

Lilypad pond (pl. 8). This species has broader seeds 

with coarser surface reticulum than other species in 

this area. It is a montane to subalpine species in 

Colorado (Harrington, 1954). 

HALORAGACEAE 

Four-pored Myriophyllum pollen occurs at the same 

level as the single seed in Buckbean fen (pl. 2). The 

seed cannot be assigned to a species, but 

Myriophyllum spicatum ssp. exalbescens and M. verticiUatum are the only two species that grow in the 

park today (McDougall and Baggley, 1956). Seeds of 

Myriophyllum occur abundantly in cores from nearby 

sites. 

LORANTHACEAE 

No attempt was made to identify Arceuthobium 

pollen to species because of insufficient reference 

material (pl. 2). Three species occur in northwest 

Wyoming: A. douglasii infects Pseudotsuga as its 

principal host, A. campylopodum is parasitic mainly 

on Pinus ponderosa, and A. americanum is parasitic on 

Pinus contorta (Hawksworth and Wiens, 1972). 

Because the fossil pollen occurs mainly in the Pinus 

contorta zone, the moc;t likely species is Arceuthobium 

americanum. 

MENYANTHACEAE 

Menyanthes trifoliata pollen and seeds both can be 

confidently identified from the upper part of the 

Buckbean fen core (pls. 3 and 6). The plant now grows 

on the fen and elsewhere in the park. 

NYMPHAEACEAE 

Nuphar luteum ssp. polysepalum is distinct from 

eastern subspecies of the species because of its longer 

seeds (pl. 7). Pollen of this genus is also well 

represented and is easily identified by its 

monosulcate, echinate grains (pl. 2). 

ONAGRACEAE 

Epilobium seeds are found in several cores and in a 

surface sample. The Epilobium lactiflorum seed that 

occurs in Lilypad pond is small and has parallel rows of 

separate, long, narrow tubercles (pl. 8). The 

specimens in the Pinus contorta zone of Buckbean fen 

are more elongate, with rows of short projections; the 

rows are connected by low crossbars (pl. 8). They are 

referred to Epilobium glandulosum type which 

includes E. adenocaulon. 

POLEMONIACEAE 

Pollen of Polemonium (pl. 3) is distinct from other 

genera in the family, because of its striate or 

striate-reticulate sculpture and its periporate 

apertures (Stuchlik, 1967). Reference collections were 

insufficient to attempt a specific identification. 

POLYGONACEAE 

Pollen of Polygonum (including Bistorta) can be 

separated into three types. Bistorta type is 

tricolporate, tectate, prolate, and psilate, with 

prominent columellae; it has slitlike furrows and an 

equidimensional pore (pl. 3). Polygonum persicaria 

type is periporate with a coarse reticulum. Polygonum 

ramosissimum type is tricolporate, prolate, and 

psilate, but with transverse furrows. Bistorta type 

includes Bistorta bistortoides and Bistorta vivipara, 

both subalpine to alpine plants. Because of incomplete 

reference material, species included in the other two 

types are unknown. 

Single pollen grains of Koenigia and Oxyria type 

were found at 850 em in Buckbean fen. Koenigia pollen 

is periporate, echinate, and tectate, with about 12 

small, elongate pores. The fossil is about 22 ~ m 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E29 

(micrometres) in diameter, whereas the reference 

material is about 25 lAm. Oxyria-type pollen is 

spheroidal, tricolporate, psilate, and tectate, with 

slit-shaped furrows and small pores. Both plants are 

restricted to arctic-alpine envirqnments, and Koenigia 

is rare in the modern flora of the tundra in the Rocky 

Mountains (Weber, 1967). 

The pollen of Eriogonum or Rumex could not be 

separated into morphological types. However, one 

fragmentary and one whole seed of Rumex salicifolius 

(pl. 6) suggest that Rumex pollen (pl. 4) belongs to 

that species in the Picea-Juniperus-Pinus albicaulis 

zone. The seeds also resemble the adventive R. 

crispus but are distinct in size and shape from other 

native species. Rumex fueginus seeds and perianths 

are present in the Pinus contorta zone of Buckbean fen 

and they are abundant in the upper zones of other 

cores in the area. The distinctive denticulate valves of 

R. fueginus (pl. 6) distinguish it from all other species. 

The separate seeds closely resemble those of R. 

paucifolius. 

RANUNCULACEAE 

Only two fruits of Ranunculus aquatilis were found 

(pl. 8). The distinctive ribbed achenes distinguish it 

from all other species of Ranunculus. 

ROSACEAE 

Potentilla seeds were difficult to identify as to 

species because of the large number of species in the 

Rocky Mountain area. The PotentiUa cf. gracilis is 

smaller than all the reference material, but it comes 

closest in size and shape to Potentilla gracilis (pl. 8). 

Potentilla biennis type matches both the striated 

seeds of P. biennis and P. norvegica (pl. 8). For 

plant-geographical and autoecological reasons, the 

seeds are referred to asP. biennis. The large, broad 

seeds of P. palustris are distinct from all other species 

(pl. 8), and the striate pollen is also distinctive (pl. 4). 

Sibbaldia procumbens, a genus closely related to 

Potentilla, has larger and broader seeds distinct in 

shape from species of Potentilla. It is a subalpine and 

alpine plant. 

SALICACEAE 

The bracts referred to Populus balsamifera (pl. 6) 

also resemble Populus trichocarpa. The former is a 

boreal forest tree extending from Northeastern United 

States through western Canada with disjunctions 

south to the Yellowstone National Park area (Fowells, 

1965). Populus trichocarpa is a west coast tree whose 

distribution extends inland to the Yellowstone 

National Park area (Fowells, 1965). Their present 

ranges overlap, and the acceptance of Populus 

balsamifera in Yellowstone National Park by 

McDougall and Baggley (1956) is in need of 

verification. Fossils of these two species are difficult 

to distinguish, but bracts of P. balsamifera are 

narrower than those of P. trichocarpa in our material. 

Populus trichocarpa grows along stream banks and 

flood plains at low elevations. Populus balsamifera is 

not strictly riparian, and it grows in the montane and 

subalpine zones up to 11,000 feet (Porter, 1967; 

Weber, 1967). Ecological and morphological considerations support the referral of the fossil bracts to 

Populus balsamifera, and the pollen probably is of this 

species also (pl. 4). 

A fairly distinct morphologic type of Salix pollen (pl. 

4) was found in some alpine surface samples. Inadequate reference material for this genus has made 

careful study unwarranted. Buds of Salix have not 

been identified to species, but a few leaf bases can 

tentatively be referred to Salix subcoerulea. Seed and 

leaf reference collections are also incomplete for this 

genus. 

SAXIFRAGACEAE 

A single seed of Saxifraga caespitosa was found in 

the Lilypad pond core (pl. 10). The seed is 

ovate-oblong and has a surface pattern of linear rows 

of tiny beadlike projections. Only Saxifraga rivularis 

has a similar beaded pattern, but in that species the 

beads form a reticulum. I have collected Saxifraga 

caespitosa from the Two Ocean Plateau and from the 

Beartooth Plateau, and it is an alpine species. 

Another saxifrage seed is referred to Saxifraga 

rhomboidea (pl. 10). It also is ovate-oblong, and its 

surface is traversed by discontinuous, often indistinct 

ridges. This species ranges from the plains to the 

alpine tundra. 

CYPERACEAE 

Although the genus Carex is represented by many 

species in the Rocky Mountain region, collections from 

wet-ground species in Yellowstone National Park have 

allowed several species to be identified from their 

fruits. Usually the perigynium, an inflated sac 

covering the achene, must be present for 

identification. 

Several fruits with perigynia of Carex aquatilis 

were found (pl. 9). Separate achenes, when 

preservation was excellent, were placed in this 

species, but others less well preserved or with 

different morphology were placed under Carex 

biconvex. Carex aquatilis is the commonest of the 

Carex species with biconvex achenes that grow in wet 

places in Yellowstone National Park. 

Carex canescens fruits are biconvex and their small 

plump perigynia are strongly veined (pl. 9). Carex 

diandra fruits (pl. 9) have a corky-based perigynium 

that tightly encases the achene. The achenes are 

shaped somewhat like Scirpus fruits, but they are 

round rather than biconvex in cross section. Achene 
E30 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

and perigynium are usually found together but can be 

recognized separately. Carex limosa fruits were never 

found with perigynia. The achenes are weakly 

triangular to round in cross section, obovate, and 

usually indented in one side (pl. 7). They match 

reference material perfectly, and Carex limosa grows 

at present in the Carex diandra-PotentiUa palustris 

community on the fen. Carex vesicaria and C. 

utriculi:Lta are two other species now common on the 

fen. Their perigynia are distinguished by shape; C. 

vesicaria perigynia taper gradually to a slender base, 

whereas those of C. utriculi:Lta are abruptly expanded 

to a broader base (pl. 7). 

A single Eleocharis macrostachya fruit, corroded 

but identifiable, was found in the Buckbean fen core 

(pl. 9). These fruits are much more common in other 

cores from this area. These biconvex fruits with the 

small, broad-based tubercle connected only at the top 

of the fruit are easily separable from other species in 

the area. 

GRAMINEAE 

Seeds of this family generally have thin seed coats 

and only a few genera with thick seed coats fossilize. 

Spikelets of Calilmagrostis are abundant in one 

macrofossil surface sample from Buckbean fen but are 

not found as fossils. Calilmagrostis canadensis and C. 

inexpansa are common on the fen surface today, and 

they probably grew there throughout most of 

postglacial time. 

Seeds of Glyceria maxima ssp. grandis are present 

at only one horizon of the Buckbean fen core but are 

abundant in other cores from the area (pl. 9). This 

species has seeds similar to G. borealis, but the seed 

tip is blunt in G. maxima and sharp in G. borealis. The 

reference specimens are somewhat larger than the 

fossil material. Other species are quite different in 

morphology and size. 

NAIADACEAE 

Seeds of Naias flexilis are easily distinguishable 

from other species in the genus by size and surface 

texture (pl. 9). This species is not reported from the 

present flora of Wyoming or Colorado, though it does 

occur in Utah (Porter, 1963; Matsumura and 

Harrington, 1955). I have found seeds of Naias flexilis 

in approximately the midpostglacial from four ponds 

in Yellowstone National Park. The plant probably 

grows in Wyoming and Colorado, but it is unreported 

because it is inconspicuous and because aquatic plants 

are not commonly collected. 

Several species of Potamogeton have very 

distinctive fruit-stones, and many of the North 

American species are treated in keys (Jessen, 1955; 

Martin and Barkley, 1961). In Potamogeton alpinus 

the lid reaches the top of the fruit-stone and is remote 

from the style base. One specimen was found with its 

soft outer covering intact (pl. 7). Potamogeton 

filiforrnis fruit-stones also have the lid remote from 

the style base, but the lid does not reach the top of the 

fruit-stone (pl. 7). It is similar to but smaller than 

fruit-stones of P. vaginatus and P. pectinatus. P. 

gramineus fruit-stones are rather small with a low 

central depression and a low-keeled lid (pl. 7). One 

fruit-stone w'ithout a lid best matches P. iUinoensis, 

but certain identification is not possible. It occurs with 

a fruit-stone of P. alpinus. 

TYPHACEAE 

Fruits of Typha cannot be identified to species (pl. 

10). Pollen of Typha liltifolia remains in tetrads, so this 

species is recognizable (pl. 2). Typha angustifolia 

pollen cannot be distinguished from pollen of 

Sparganium or broken tetrads of Typha liltijolia, and 

the pollen is here called Sparganium type because 

fruits of Sparganium angustijolium and S. minimum 

have been found in other nearby cores. 

OTHER TYPES OF FOSSILS 

Other types of macrofossils were tallied on a scale 

from one (rare) to five (very abundant). No attempt 

was made to differentiate among bryophyte spores, 

although the one shown on plate 1 is the commonest 

type. Abundance of Sphagnum leaves was noted, 

because the two types of cells in the leaves make them 

easy to recognize. 

ALGAE 

Pediastrum colonies (pl. 4) were counted and 

plotted in the pollen diagram (fig. 15) because they 

indicate an aquatic environment. They are present in 

many surface samples, especially those from larger or 

deeper ponds. 

Oogonia of charophytes were tallied in the 

macrofossil diagrams (figs. 17 and 18). They disappear 

above 820 em in the Buckbean fen core, but they are 

present in younger horizons from other cores in the 

area. 

One species of diatom (Melosira?) was large enough 

to be caught by the 140-mesh sieve; specimens were 

sent to R. C. Bright for identification. The species 

occurs below 800 em in Buckbean fen and Lilypad pond 

cores. 

Statoblasts of freshwater bryozo~ and shells of 

rhizopods were not further identified. Both occur 

mainly in the small pond stage of the Buckbean fen 

core in the interval 275 - 4 75 em. 

DESCRIPTION OF POLLEN ZONES 

PICEA-JUNIPERUS-PJNUS ALBICA ULIS 

ZONE (960-770cm) 

The basal zone is defined by relatively low (30- 50 

percent) Pinus pollen (dominantly Pinus albicaulis 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E31 

type) and by maxima in Picea, Abies, Juniperus, 

Salix, Artemisia, Gramineae, Compositae (subfamilies 

Tubuliflorae and Liguliflorae), and Rumex (fig. 15). A 

mixture of subalpine and alpine macrofossils is present 

in this zone, and large diatoms (longer than 0.5 mm) 

and charophytes are nearly limited to this zone (figs. 

17 and 18). The concentration of the alga Pediastrum 

reaches 40 percent of the pollen sum at the base, and 

bryophyte spores are consistently present. 

This pollen zone occurs in the lower 190 em of the 

core from Buckbean fen and the lower 200 em of the 

Lilypad pond core (figs. 15, 17, and 18). The sediment 

in both sections overlies a basal gravel and consists of 

100-200 em of gray sandy silts (table 5). The sandy 

silts in this zone contain too little carbon for C 14 -

dating, but on the basis of two other dates on 

deglaciation (Sullivan and others, 1970; Bender and 

others, 1971) the sediments in this zone probably 

began to accumulate before 13,500 years ago. Also, an 

ash layer near the base of the Lilypad pond core (table 

5) may represent the Glacier Peak ash dated at 12,000 

years B.P. (Wilcox, 1965), but the ash was too thin and 

mixed with sediment to be identified. The age of the 

sediments at the top of the zone is unknown here, but 

the top of the correlative zone at Cub Creek pond is 

dated by C 14 at 11,630±180 years B.P. (I- 2285, 

Waddington and Wright, 1974). The zone is divided 

into two subzones on the basis of pollen and plant 

macrofossils: a lower Betula subzone and an upper 

Populus subzone. 

BETULA SUBZONE (960 -875 em) 

The Betula subzone is defined primarily by low but 

persistent values (1- 3.5 percent) of Betula pollen (fig. 

15). Rumex (dock) pollen is consistently present, and 

Compositae pollen, especially subfamily Liguliflorae, 

is most common in this subzone. Pinus albicaulis/ 

Pinus contorta ratios are highest in this subzone, 

ranging from 5.5 to 27 (fig. 19). 

The lower 100 em of the Lilypad pond core (fig. 18) 

is tentatively referred to this subzone on the basis of 

(1) presence of mixed alpine- and subalpine-plant 

macrofossils, (2) distribution of Betula glandulosa 

(bog bireh) fruits and catkin scales, and (3) rare 

presence of arboreal macrofossils. ·The Cub Creek 

pond sequence (Waddington and Wright, 1970) shows 

a similar Betula pollen peak at the base of the core. 

Betula gklndulosa and Rumex salicifolius (willow 

dock) were identified from macrofossils from the 

Lilypad pond core (fig. 18), and these are probably the 

species represented by pollen (fig. 15). The BetukL 

pollen is small mostly less than 21 1-' m in diameter. 

BetukL glandulosa is a common shrub of wet subalpine 

areas in the Rocky Mountains (Weber, 1967). Rumex 

TABLE 5.-Lithologic description of Buckbean fen and basal 

section of Lilypad pond 

Penetration Core length 

(em) (em) 

0-100 0-81 

100 - 200 100 - 188 

200 -300 200 - 290 

300 - 400 300 - 383 

400 - 500 400 - 487 

500 -600 500 - 585 

600 -700 600 - 699 

700 - 800 700- 783 

800- 890 800 - 884 

890 - 975 890 -960 

Description 

Buckbean fen 

Sedge peat, dark-brown fibrous; with intertwined rootlets. Rootlets of woody plants 

(Salix spp?) from 0 - 10 em. Sedge peat, dark-brown, somewhat decomposed; not so fibrous as 0-81 em, coarse Carex leaves from 100 - 115 em; abundant 

bryophytes from 130- 188 em. Sedge peat, brown, somewhat decomposed, 

with bryophytes common. Peat, brown, with sedge remains, wood 

fragments, and Nuphar seeds from 300 - 340 em; mainly bryophyte peat from 340-

383cm. 

Bryophyte peat, brown from 400 - 410 em, 

grading to olive-colored gyttja at 425 em. Fine-grained detrital peat from 430 - 487 

em, black from 430 - 442 em, brown from 

442-487 em. Gyttja (organic sediments of eutrophic 

lakes), brown, silty, fine-grained, 

inelastic, crumbly. 

Gyttja, brown, silty, fine-grained, inelastic, 

crumbly from 600- 620, solid from 620 - 640cm. 

Gyttja, brown, silty, clayey, inelastic; 

crumbly from 700 - 710 and 751 - 783 em, 

firm elsewhere, dark band from 717-722. 

Silt, organic, highly diatomaceous; finely laminated (varved?) from 810-856 em, 

crumbly from 800 - 820 em, very firm from 

820 - 840 em, sand layer at 805 em, becoming gray silt mottled with dark spots from 

856 - 884 em. Sand lense at 873 em. Silt, gray, sandy, highly diatomaceous, with 

dark mottling from 890-928 em, lenses of 

gray medium-grained sand at 910 and 

951.5 - 954.5 em, crumbly from 939-945 

em, firm elsewhere. Pebbles impacted into 

bottom of core. 

Lilypadpond 

800 - 900 800 - 892 Silt, gray, sandy, highly diatomaceous below 

825 em, sand layer at 854 - 855 em, 

streaks of black sand at 881 and 883.5 em, 

gray clay from 887 - 890 em, laminated 

brown and buff silt from 890 - 892 em. 900-1,000 900-1,000 Clay, gray, sticky, from 907-910 em; coarse gray sand from 900 - 907 and 910 - 917 em. Silt from 917-1,000 em: gray, sandy, 

dark.layers at 950, 953.4, 996.5, and 997.5 

em; ash layer at 974.2- 974.5 em. 

salicifolius grows on dry sites at elevations from 3,500 

to 9,500 feet in Wyoming (Porter, 1968). 

Several local habitats are suggested by the pollen 

and macrofossils (figs. 15, 17, and 18). Rumex 

salicijolius, Potentilla cf. gracilis, and Descurainia 

californica are weedy species that probably grew in 

dry, disturbed areas or along the shores of the 

ancestral lake. Juniperus (probably J. communis) and 

various composites may have shared dry forest 

openings with these species. Pollen of steppe 
E32 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

CONIFEROUS FOREST 

ZONE SUBZONE 

AbiesPinus Pinus 

contorta 

Pinus 

contorta I 

contorta 

Pinus 

I 

1 

contortaPinus 

I albicau/is 

PiceaJuniperus1 Populus 

Pinus 

....J 

w<t: 

....J> 

a_O: 

2w 

<t:f-

(/)~ 

SED I-

~ :::, 

.~ 

~ 

"' 

.-SUBALPINE 

·c: •0 <:: e. 

.§ "' "' <..> 

<1l -S? <:>, 

<:: 

<1l ~ 

~ -~ 

<:: ~ :::, 

.E ~ 

E: ~ "' Cl 

"' <..> 

.Q 

~ 

SAMPLE 

NO. AND 

CARBON14 DATE MENT DEPTH~ 

TYPE (m) ~ "' <1l ~ -!:: .Q 

~ ~ :::, -2- Cl. <:: (years B.P.) 

~J o Peat ~ 

L__ -

I Pe aT. ~ -

~ It ~ 

W-2280 J Peaj = 

2,470 ± 250. -

l = 

I eaJ~ L_JJ-

. ~~;,., J ,,, ~c- 5.390 ± 250 L J _ 

9,240 W- 2284 ± 300 r~ -

~ gan1c 

mud 

. :--T ~ 

OrW-2285 J ganic 

11,550 ± 350 I mud 

•••.•••.••• 1 ••••• 

L 

ri 

1 

\Sandy 

si It 

.. ·L···· 

I 

\

Sandy 

silt 

9 -

~ oq: ~ ~ 

--- ----t ----

1 i 

" 

EXPLANATION 

• Seeds or seedlike fruits 

o Other macrofossils 

' Fragments 

-~ 

::::: 

<..> 

~ <:>, 

t 

.!:!1 

~ <:: 

~ 

Cl 

~ 

I 

I 

. .... ·\·· ................ . 

fl'"r'"'l 0 5 10 Number of fossils 

FIGURE 17 (above and right). -Plant macrofossils from Buckbean fen core. 

elements, such as Artemisia, Cheno-Ams, and 

Sarcobatus, is common in this subzone, but it seems 

ecologically unreasonable that these plants grew near 

the coring sites. Woodland or tundra species of 

Artemisia may have contributed some pollen, but 

long-distance transport probably accounted for much 

of the pollen of steppe elements, as it apparently does 

at present in alpine sites. 

Pollen of Potamogeton, fruit-stones of Potamogeton 

alpinus and P. filiformis, and fruits of Ranunculus 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN 

FEN AQUAT IC MISCE LLANEOUS FOSSILS 

•§ 

~ ~ 

Ctl ~ Cl.. C1) 

~ g. ~ <1J 

~ Tota l ~ ~ 

ti: Carex ~ Cj canescans 

Total Potentilla --

~---+.....(\ palustris 1 

Tota l Carex : 

diandra 

I 

~ 

~ 

.... ~ ---

. 

I 

. = :J -g :.. .0 

I 

-I 

. - 1=-

1 :-

1 :. 

I ! 

. I 

I I I 

i I 

I 

-

c 

~ 

0 

c 

.:.:. 

c 

::J 

I 

r 

- I I :.. I 

: --+--+------ - I I L -

. .. • .. ...• . • • . .• . I . ·· ·· .L ·i. ·. I I .. , ..... . . .. .. . . 

L _J L~ ~ I 

. 

r---4-4-----4--4--4-------

- I I I tf------ J---+---.----------j ---+ -+------ ~- . + - .. _I_ .-~ .... I I _ -- --l- 1 I I I 

f------+-- - -----1-

--

. 

I I I 

t ~~ 

I I .. .... .. ·J·· .... 

~ 

r 

I 

I 

Ql 

0 

a. 

0 

0 

Ql 

>. 

..c 

a. 

~ u 

·t ·-

1 

p 

F . r .. . . . . . . . I'""' . . . ~· 

-

~ 

I ~ 

"' a. 

a. 

:.c 

~ 

"' Ql 

u 

0 

~ 

u 

NO. OF UN ITS ABUNDA CE 

Rare 

In frequent 

Common 

4 Abundant 

Very abundant 

-o 

0 

a. 

.§ 

..c 

a: 

E33 

Ql 

> 

"' Ql 

aquatilis (water crowfoot) indicate that pioneer 

aquatics had colonized the shallow lake margins. A 

few pollen grains of Typha latifolia (broadleaf cattail) 

and Sparganium (burreed) type suggests that these 

plants may also have grown in shallow water or along 

the shore (figs. 15, 17, and 18). 

Macrofossils of Saxifraga caespitosa, S. rhomboidea, PotentiUa sp., Sibbaldia procumbens, and Betula 

glandulosa, and pollen of Bistorta and Polemonium 

suggest that subalpine or alpine meadows were 

present in the area (figs. 17 and 18). These plants at 

present are common in the alpine parts of the Two 
E34 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

ALPIN E 

~ 

2 

~ 

r3 

§, 

(I) 

~ 

E 

:::J 

.... (I) 0 

% <ll 

~ (.) 0 

.!)? .Q 

E 

0 u -c: 

.... E §, ~ 

.Q (I) 

~ 

SUBALPINE 

~ ~ (I) ~ ~ 'ti 

"' 0 .E ~ ·~ c:: tl'> ~ ~ (I) (I) 

l::J (I) E ~ u c:: ·~ ~ (I) 

.!)? :::? tl'> .Q .!)? tl'> c:: "' ~ .!)? (I) <ll :::J c:: ~ "' (I) ~ 

~ ·;;: 2 :::J <ll Q. ~ .s (.) SEDIMENT ·;;: (I) <ll 0 0 ZON E SU BZON E TYPE DEPTH(m) ~ (/) (() Cl i:i: Cl Cl 

8 --~-- ------~--~--~r---r---~--~--~---

Pice aPopulus 

Junip erusPinus Betula 

albicaulis 

Sandy 

si It 

Sandy 

si It 

xxxxxxx 

ash / 

9 

L.._._ ______ ...___ 1 0 

····· 

l''''l''''l''''l''''l''''l''''l''''llllljlllljl I ''I 

EXPLANATION 

• Seeds or seedli ke fruits 

0 Other macrofossils 

C Fragments 

F IGURE 18 (above and right). - Plant macrofossils from lower 2 metres of Lilypad pond core. 

Ocean Plateau, but only Saxifraga caespitosa is 

limited to the alpine tundra. 

Rare Picea and Pinus albicaulis needles and a 

Populus bract suggest that only a few trees may have 

grown in favorable nearby habitats (figs. 17 and 18). 

Pollen percentages of Picea, Abies, and nonarboreal 

types compare best with modern surface samples from 

low alpine and parkland sites (figs. 13 and 15). Pinus 

pollen values are about 20 percent lower in the Betuw 

subzone than in these surface samples. Low 

tree-pollen percentages might be expected at that 

time if the surface of the plateau was covered by 

tundra or mixed parkland and tundra instead of forest. 

Pollen ratios also support the conclusion that the site 

was near timberline during Betuw subzone time. 

Pinus albicaulis/Pinus contorta and Gramineae/Pinus 

ratios are high (1 - 11 and 0.025- 0.2) in modern 

surface samples collected at or above timberline (fig. 

14). Both ratios are high (5.5 -11 and 0.1 - 0.33) in the 

Betuw subzone (fig. 19). 

The proximity of trees to the coring site is difficult 

to determine. No nearby forested areas below this 

tundra or parkland were present, because the 

ancestral lake covered all lower ground in the vicinity. 

Conifer needles can blow for some miles when caught 

in the updraft of large forest fires. R. F. Bucknam 

and B. B. Kropf (written commun., 1969) reported 

conifer needles falling in Denver, Colo., during a 

forest fire on Mount Evans, which lies about 35 miles 

west and at least 6,000 feet higher. All the needles 

were carbonized, however, whereas most needles 

from the Betuw subzone in the core studied were not. 

Picea, Abies, Pinus albicaulis, and possibly Populus 

balsamifera (balsam poplar) were probably the only 

trees growing on the plateau parklands at this time. 

Pinus contorta type pollen percentages of less than 2 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E35 

DAM P ECOL . M ISCE LLANEOUS 

MONTAN E GROU ND A QU AT IC IN D ET. FOSS ILS 

'1l QJ QJ ~ 

~ Q. Q. E "' c::: ~ ~ -~ ~ '- "' ~ ~ 0 ro 

~ -~ ::J '1l x '1l Q. Q. "' c::: 

~ ~ ::J 0 Q. QJ 

~ c::: '0 QJ ;;: tt > ~ ~ ~ c::: > c::: '1l 0 L E ro c ~ Q. ~ 

~ ..Q ~ 0 2 "' <ll ~ QJ 0 ~ ~ u ::J ")( ~ f: c::: ~ Cll :; c > ro 

-~ ~ ~ "' '1l ii t::ll Cll ·;:;; s L a; ::J )( Q. 0 ~ .-;:::: 0 Q. u -o c::: f: c::: 0 ::J c::: Cll .9- )( ::J V). Q. c e 0 QJ t::ll ~ !:: f: Cll ~ -~ E -o '1l 

"' '- c::: .:.:. ro f:l ..c:: Cll 0 ::J 0 '- ci: '1l '1l 0 c L ro 

a co Cl Q.. c:c: c:c: c:c: < u ::l u u ....J ~ 

1 I I I I 1 'I'' 1'' ''1'' ''1''' 'I I''' I I' I 'I I I' I 1' I' I I I' I' I I I'' 1 II I I I I I ''I I I I I I I '''IIIII] I '''I I I ''1''''1 I 11 I I I I I 1 I 

1 111 11 1111 1 

NO. OF ABU DANCE ITS 

0 5 10 Numbers of fossils I Rare 

Infrequ ent 

percent (fig. 15) suggest that this tree was not present 

on theY ellowstone plateau, although it probably grew 

in lowlands around the margins of the plateau. 

Trees apparently did not require a long time to 

migrate onto the plateau after the melting of the 

icecap. The high ridges and plateaus in the southern 

and eastern parts of the park would have been above 

climatic treeline during this time and would have 

acted as barriers to migration. Migration probably 

took place along valleys, progressing gradually inward 

to the Southeast Arm of Yellowstone Lake as the 

valleys became free of ice. Scattered trees may have 

been present within a few miles of the coring area 

when it first became exposed. 

An alternate hypothesis for forest migration would 

be that trees survived locally on nunataks and 

migrated a shorter distance down to the coring area. 

2 

3 Comm on 

4 Abundant 

5 Very abundant 

However, no nunataks are known nearby that would 

have been below the climatic treeline. 

The pollen and macrofossils of this subzone suggest 

subalpine to alpine vegetation and a cold, wet climate. 

Present lack of climatic stations in the subalpine and 

alpine areas of Yellowstone National Park makes it 

difficult to quantify the late-glacial climate, but 

average July temperature below 50°F now 

characterizes the areas above treeline (Marr and 

others, 1968) or north of it (Wolfe and Leopold, 1967). 

If subalpine spruce-fir-whitebark pine parkland 

occurred near Yellowstone Lake, such conditions 

probably prevailed. 

POPULUS SUBZONE (875- 770 em) 

The Populus subzone of the Picea-Abies-Pinus 

albicaulis zone is defined by a peak in Populus pollen 

and by bracts of Populus balsamifera (figs. 15, 17, and 
E36 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

18). A peak in the curve for Ambrosia also occurs in 

this subzone (fig. 15). Alpine-plant macrofossils are no 

longer present, Picea and Pinus albicaulis needles are 

more common, and Juniperus communis needles 

appear (figs. 17 and 18). Pinus albicaulis/Pinus 

contorta and Gramineae/ Pinus ratios decrease 

throughout this zone and range from 1.1 to 7.5 and 

from 0.047 to 0.228, respectively (fig. 19). 

Several local habitats may be inferred from the 

fossils in this subzone. Betula glandulosa, Potentilla 

cf. gracilis, Rorippa islandica (marshcress) type, and 

Epilobium cf. lactiflorum (pale willow-herb) macrofossils (fig. 18) suggest a moist subalpine meadow 

nearby. A dry, open subalpine environment, such as 

might have been found near the shores of Yellowstone 

Lake, is inferred from macrofossils of Rumex 

salicifolius and Potentilla biennis type. The fossil 

aquatic flora includes Ranunculus aquatilis, Potamogeton alpinus, and Naias flexilis (naiad). Naias 

flexilis is not reported from the modern floras of 

Wyoming or Colorado. Single pollen grains of Oxyria 

U) 

LU 

100 

200 

300 

a: 400 1-

l.U 

2 

1-

z 

LU 

(..) 

~ 

I t 600 LU 

0 

800 

900 

960 

I 

GRAMINEAE/P/NUS POLLEN RATIO 

AGE, IN 

YEARS B.P. 

SUBZONE 

~) BOUNDARIES 

<....._.....Graminae/ Pinus "'> / 2,470 ( 

I 

ca. 5,000 

5,590 

9,240 

ca.10,160 

Pinus albicaulis/Pinus conto;tf,550 

ca. 11,630 

----- -~-====--

Picea-Abies-Pinus 

contorta subzone 

Pinus contorta 

subzone 

Pim:s contortaPinus albicaulis 

subzone 

Populus subzone 

----- ·-------------------·--17 

-------:-=~===-~=-- 27 

16 

2 3 4 5 6 8 9 10 11 12 13 14 

P. ALB/CAUL/SIP. CONTORTA POLLEN RATIO 

FIGURE 19.-Ratios for fossil pollen from Buckbean fen. 

(alpine sorrel) and Koenigia islandica at 850 em 

suggest that alpine plants may have persisted for a 

while on exposed sites. 

Picea engelrnannii, Pinus albicaulis, Populus 

balsamifera, and probably Abies lasiocarpa were 

present locally in a subalpine parkland environment. 

This interpretation is suggested by analogy with 

surface samples and from the composition of the pollen 

and plant-macrofossil spectra. A closed Picea-AbiesPinus albicaulis forest is ruled out by the high 

nonarboreal pollen curves and high Gramineae/Pinus 

ratios that typify surface samples from modern 

parkland or tundra (figs. 14, 15, and 19). 

Populus balsamifera probably was a pioneer species 

along the shores of Yellowstone Lake, perhaps as 

early as during the previous subzone. Populus 

trichocarpa (black cottonwood), a closely related 

species, is an early migrant onto deglaciated surfaces 

in southeast Alaska (Lawrence, 1958). Populus pollen 

maxima indicate that it was an early migrant in 

northwest Minnesota after deglaciation (McAndrews, 

1967), and macrofossils of three species, including P. 

balsamifera, were found in sediments of late glacial 

age in southern Manitoba (Ritchie and de Vries, 1964). 

To summarize the environments of the Picea-AbiesPinus albicaulis zone, the basal subzone represents an 

environment at or slightly above timberline with few, 

if any, trees present. During the time of the upper 

subzone, trees were present in a subalpine parklandtype vegetation. The climate for this zone was 

probably comparable to that of the high subalpine or 

low alpine associations today in Yellowstone Park. 

Treeline was approximately 2,000 feet lower than it is 

today. 

PINUS CONTORTA ZONE(770-0cm) 

This zone is defined by high percentages ( 65 - 88 

percent) of the total pine pollen and by Pinus contorta 

macrofossils (figs. 15 and 17). Artemisia declines from 

more than 20 to less than 10 percent in this zone, and 

values of Juniperus, Picea, Abies, Betula, and most 

nonarboreal pollen are low (fig. 15). 

The sediments in this zone are silty gyttja in the 

interval 770 - 500 em, transitional organic detritus in 

the interval500 - 410 em, and peat from 410 em to the 

surface (table 5). No dates are available from 

sediments at the base of this zone, but a date at the 

zone boundary at Cub Creek pond is 11,630 ± 180 years 

B.P. (sample I-2285; Waddington and Wright, 1970). 

The zone is divided into the following three 

subzones: the Pinus contorta-Pinus albicaulis subzone 

(770- 600 em), the Pinus contorta subzone (600- 420 

em), and the Picea-Abies-Pinus contorta subzone 

(420- 0 em) (fig. 15, table 3). 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E37 

PINUS CONTORTA-PINUSALBICAULIS SUBZONE 

(770-600 em) 

This subzone is defined by a resurgence of Pinus 

albicaulis/Pinus contorta ratios up to 8.3 (fig. 19), and 

the occurrence of needles of both pine species (fig. 17). 

Pinus pollen percentages average 65 - 70 percent, and 

Artemisia ranges from 15 to 20 percent (fig. 15). 

Arceuthobium (dwarf mistletoe) is persistently 

present, and a few grains of Pseudotsuga occur. 

Concentrations of Picea, Abies, Juniperus, Populus, 

Betula, Salix, Ambrosia, Compositae, and Gramineae, 

all significant in the lower subzones, are several times 

lower in this subzone (fig. 15). 

A radiocarbon date near the base of this subzone 

gives an age of 11,550 ± 350 years B.P. The age of the 

top of this subzone is interpolated to be 10,160 years 

B.P. (figs. 15 and 16, table 3), using the rate of 

sedimentation calculated from adjacent radiocarbon 

dates. 

The pollen spectra from this subzone compare 

approximately with modern surface samples from 

forest openings (fig. 13). Gramineae/Pinus ratios for 

this subzone are between 0.025 and 0.050; these ratios 

are lower than those of modern surface samples in 

forest openings and parklands but higher than ratios 

in closed forests (figs. 14 and 19). An open, mixed 

forest with Pinus contorta, Pinus albicaulis, and 

Pseudotsuga menziesii probably grew in the area 

during the interval represented by this subzone. 

(Pollen values of Pseudotsuga as low as 1 percent 

probably indicate its local presence, based on surface 

samples.) The most significant change in vegetation 

after deposition of the lower zone was the arrival of 

Pinus contorta and Pseudotsuga in the coring area 

(figs. 15 and 17). 

It is difficult to infer other habitats that might have 

been present during this period because few 

macrofossils other than pine needles are present. A 

few Carex fruits and a Typha fruit (fig. 17) suggest a 

possible pond-shore habitat. 

Persistence of A rceuthobium in the pollen profile, 

beginning at 730 em (fig. 15), gives evidence for a 

tentative mean annual temperature during that time. 

Its pollen appears at about the same level that Pinus 

contorta needles first appear (fig. 17). I could not 

determine the species using pollen morphology, but it 

is probably Arceuthobium americanum, a parasite 

that occurs exclusively on Pinus contorta in this 

region. It is the only species of Arceuthobium 

reported from the park by McDougall and Baggley 

(1956), but Hawksworth and Wiens (1972) reported A. 

douglasi, a parasite on Pseudotsuga, from the park as 

well. At present the upper limits of Arceuthobium 

americanum coincide with the 30°F mean annual 

isotherm in Colorado and Wyoming (Gill, 1957), 

suggesting that the temperature when Arceuthobium 

first appeared was about the same as it is now. 

The coexistence of Pinus contorta, Pinus albicaulis, 

and probably Pseudotsuga menziesii, and the low 

values of Pice a and Abies suggest a climate drier than 

the climate of the preceding zone and also the present 

climate. 

PINUS CONTORTA SUBZONE 

(600-420 em) 

This subzone is defined by 70 - 80 percent Pinus 

pollen, low ratios of Pinus albicaulis!Pinus contorta 

pollen, and needles of Pinus contorta (figs. 15, 17, and 

19). Pseudotsuga pollen is less common than in the 

preceding subzone, and Picea and Abies are low 

throughout. Artemisia pollen ranges from 10 to 15 

percent, and Arceuthobium and Alnus are present at 

low but persistent values (fig. 15). 

A sediment sample from interval500- 541 em in the 

Buckbean fen core gives a C 14 date of 9,240±300 years 

B.P. (W- 2284). Another sample from interval 

440-460 em is dated at 5,390±250 . years B.P. 

(W- 2281). Interpolation between older and younger 

dates suggests that this subzone began about 10,160 

years ago and ended about 5,000 years ago (fig. 15, 

table 3), but the 4,000-year span of the dates in the 

zone, over only a 70-cm interval, suggests a hiatus in 

the core. (See fig. 16.) 

The fossil assemblage suggests that a virtually pure 

Pinus contorta forest was the dominat vegetation 

association around the coring site during this period. 

Fossils from local vegetation types are poorly 

represented, especially from interval 600 -487 em in 

this subzone. 

From interval 487 - 420 em, macrofossils of Nuphar 

luteum ssp. polysepalum, Naias flexilis, Myriophyllum 

sp. (watermilfoil), Potamogeton gramineus, and 

CeratophyUum demersum (hornwort) and pollen of 

Nuphar and Myriophyllum suggest a small, 

warm-water pond habitat (fig. 17). The presence of 

this habitat requires that Yellowstone Lake had fallen 

to a level within 15 feet of its present level by about 

5,000 years ago. 

One fragment of an Alnus tenuifolia (thinleaf alder) 

fruit at 405 em (fig. 17) suggests that the Alnus pollen 

is also of that species. It is the only species of Alnus 

that now occurs in Wyoming (Porter, 1967), and it 

suggests that the habitat was the margin of a lake, 

pond, or fen. 

Macrofossils of Glyceria maxima ssp. grandis (large 

mannagrass), Rumex fueginus, Carex utriculata, and 
E38 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

Typha sp. also provide evidence for a wet-ground 

vegetation around the margins of the pond (fig. 17). 

PICEA-ABIES-PINUS CONTORTA SUBZONE 

(420-0 em) 

This subzone is defined by low but persistent values 

of Picea and Abies pollen, by their macrofossils, and 

by low pollen ratios of Pinus albicaulis/Pinus contorta 

(figs. 15 and 19). The Artemisia curve is at its lowest 

(4 -10 percent) in the entire core. Cyperaceae pollen 

percentages are high but irregular in the subzone, but 

macrofossils indicate that the pollen comes from local 

fen species of Carex (figs. 15 and 17). 

A sample from interval 240 - 260 em gave a C 14 date 

of 2,470±250 years B.P. (W- 2280). The subzone 

represents the period from about 5,000 years ago by 

interpolation to the present. An interpolated date of 

2,800 years B.P. marks a rise in Picea, Abies, and 

Cyperaceae pollen percentages (figs. 15 and 16, table 

3). 

Pollen and macrofossils of Pt"nus contorta, Picea, 

and Abies indicate that these trees were dominant in 

the forest association when this subzone was 

deposited (figs. 15 and 17). Pollen and a needle of 

Pseudotsuga menziesii and a needle of Pinus albicaulis 

type suggest that these trees may have been present 

early during this period, but they played a decreasing 

role in the forest association. 

Most Picea needles in this subzone are charcoal. 

Frequent fires nearby might explain the carbonization, though other conifer needles are not charcoal. No 

prominent charcoal layers were observed in this core, 

but charcoal is abundant in some horizons of other 

cores taken in the area. Fires would favor propagation 

of Pinus contorta (Tackle, 1961) and might tend to 

eliminate Picea and Abies from the forest. However, 

no injurious long-term effects of fire on Picea and 

Abies can be recognized in the pollen diagram (fig. 15). 

Changes in the local environment are well 

documented in this subzone by plant macrofossils (fig. 

17). From interval 420-375 em, macrofossils of 

aquatic and pond-margin plants are still present, 

suggesting that little change in environment had 

occurred from the top of the previous subzone. 

From interval 375 - 275 em, fen plants, such as 

Carex aquatilis, C. diandra, a trigonous Carex-probably C. utricullLta-Salix sp., Menyanthes trifoliata, 

and Epilobium gllLndulosum type, appear (fig. 17). 

Nuphar luteum ssp. polysepalum pollen and seeds, 

Potamogeton fruits, and Pediastrum still are present 

(figs. 15 and 17). These macrofossils suggest that a fen 

began to encroach into the pond. The pond was 

probably becoming very shallow and was surrounded 

by sedges, grasses, and other fen plants, perhaps 

growing on a floating mat. The aquatic macrofossils 

testify that a small pond was still present. 

From 275 em to the surface, macrofossils of truly 

aquatic plants, such as Nuphar, are absent (fig. 17). 

The Cyperaceae pollen curve is high except between 

100 and 40 em and represents chiefly fen species of 

Carex. The Cyperaceae curve ranges from iO to 40 

percent in the interval 260 -175 em (fig. 15). A small 

pollen peak at 260 em is associated with many achenes 

of a trigonous Carex, probably C. utricullLta or C. 

vesicaria (figs. 15 and 17). The abrupt disappearance 

of aquatic-plant macrofossils and the abundance of 

sedges imply that this interval represents the demise 

of the pond at this coring site. 

In the interval260 - 175 em, few Carex macrofossils 

are found, even though the Cyperaceae pollen curve 

reaches its maximum at 220 em (figs. 15 and 17). 

Sphagnum moss leaves are very abundant in this 

interval, and the local sedges may have been choked 

out by this bog moss. The high Cyperaceae pollen 

values suggest that Carex was still abundant in other 

parts of the bog, however. Sphagnum warnstorfianum 

seems to be the most common Sphagnum in the park 

today, and the fossil leaves are morphologically 

similar to leaves of this species. Sphagnum liberates 

acids in its metabolic processes (Parihar, 1965); hence, 

it creates a rather acidic environment. It apparently 

grew along the margin of the pond, at least 

sporadically, throughout the earlier history of this 

site, and it was able to colonize the bog surface when 

the lake became overgrown. The most abundant 

Sphagnum interval coincides with the inferred cooler, 

moister period about 2,800 to 1,000 years B.P. (see 

following paragraphs and table 3), but its sporadic 

occurrence in the core could be controlled by local 

plant succession. 

From interval 175- 100 em, Carex diandra, C. 

aquatilis, and the trigonous Carex are very abundant, 

and definite Carex utricullLta and C. vesicariiL (with 

perigynia) and C.limosa are sparsely present (fig. 17). 

Cyperaceae pollen values range from 10 to 17 percent 

(fig. 15). Sphagnum leaves disappear above 125 em, 

and Salix sp. leaves are present. These data suggest a 

change from an acid bog to a neutral or slightly 

alkaline fen. The community was similar if not 

identical to the Carex limosa-Carex diandra-PotentilllL 

palustris community that now grows at the coring 

site. 

In the interval 100 - 40 em, Cyperaceae pollen 

curves drop to less than 2 percent, and only fruits of 

the sedge Carex diandra are abundant (figs. 15 and 

17). Several causes of this locally important change 

are possible. Recurring fires on the fen surface might 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E39 

have such an effect, but charcoal horizons that would 

record fire history are not present. The sedges 

apparently were not again choked by Sphagnum moss 

inasmuch as no leaves were found. A rising water 

level in the fen might explain all the changes. As the 

water level began to rise, Carex might have initially 

been favored over Sphagnum. As water levels 

continued to rise, the Carex too might die out locally 

and survive only on the margins of the basin. There is 

some support for this latter hypothesis. A few pollen 

grains (but no seeds) of the water lily Nuphar occur in 

this interval, whereas none occur in the adjacent 

sediments above or below (fig. 15). There also is a 

recurrence of the colonial alga Pediastrum at 80 em 

(fig. 15). These plants are suggestive of higher water 

levels, but further evidence is needed to document 

this hydrologic change. 

From a depth of 40 em to the surface, Cyperaceae 

pollen percentages rise, and fruits of Carex diandra, 

the trigonous Carex, and PotentiUa palustris are very 

abundant, at least in some horizons (figs. 15 and 17). 

Fruits of Carex utricu!J:Lta, C. vesicaria, C. limosa, C. 

aquatilis, C. canescens, and Menyanthes trifoliata 

appear near the t~p. The present fen vegetation 

apparently became reestablished above the 40-cm 

level. Slight changes in climate in this subzone are 

apparently marked by subtle shifts in pollen 

percentages. The recurrence of small amounts of Picea 

and Abies pollen, substantiated by macrofossils, 

suggests a cooler, moister climate during the last 

5,000 years than in the 11,600- to 5,000-year interval. 

Two cooling pulses may be indicated by the spruce 

pollen curve here and at Cub Creek pond (Waddington 

and Wright, 1974): a mild one that apparently began 

about 5,000 years ago, and a stronger one that began 

about 2,800 years ago. Pollen and macrofossils of 

Pinus albicaulis, Pseudotsuga menziesii, and Pinus 

contorta that occur in the interval from 5,000 to 2,800 

years ago suggest that climate was not as moist during 

that period as it was from 2,800 to the present, when 

these species were absent. 

- The Cyperaceae pollen maximum in the PiceaAbies-Pinus contorta subzone is demonstrably local, 

and it would seem logical to regard it as a successional 

phenomenon without any climatic significance. 

However, the· Cyperaceae curve at Cub Creek pond 

(Waddington and Wright, 1970) is very similar in its 

form and its relationship with the increase in Picea 

and Abies. The apparently identical timing of local 

lake to fen succession at these two sites may be 

coincidental. But this succession may also have been 

triggered at all potential sites by cooler, moister 

conditions at the end of the Altithermal. Further 

pollen and plant macrofossil work in progress at sites 

near the 15-foot lagoon should help clarify this 

problem. 

DISCUSSION AND CONCLUSIONS 

Sediments in Buckbean fen record a vegetational 

succession beginning with the Betu!J:L subzone (of the 

Picea-Juniperus-Pinus albicaulis zone) about 12,000-

14,500 years ago (table 3). The initial vegetation following deglaciations was probably open 

and tundralike with few if any trees, but subalpine as 

well as alpine plants were present. The climate was 

cold and moist, but it was probably comparable to that 

of nearby modern high subalpine or low alpine areas. 

This cold period is correlated with the late stages of 

the Pinedale Glaciation. The base of this zone is dated 

at 13,500 ± 130 years B.P. in Swan Lake Flat (sample 

WIS- 432; Bender and others, 1971). A date of 

13,140±700 years B.P. (sample W- 2037; Sullivan and 

others, 1970) on plant material in silts about 7 miles 

northeast of Buckbean fen closely postdates retreat of 

middle Pinedale ice. Waddington and Wright (1974) 

recently obtained a date of 14,360 ± 500 years B.P. 

(sample W -2780) from the base of Cub Creek pond. 

The Populus subzone marks the invasion of 

subalpine forest into the coring area. Treeline 

presumably migrated above the coring area up the 

slopes of the Two Ocean Plateau as the climate 

ameliorated. The forests were more open, but 

otherwise similar to the Picea-Abies-Pinus albicaulis 

forests in the park today. The climate was still cool 

and moist, probably much like that in the present 

subalpine vegetation association. This period probably 

postdates the last stages of melting of the middle 

Pinedale icecap. 

The basal subzone of the Pinus contorta zone 

represents about the period 11,630-10,160 years B.P. 

The Pinus contorta-Pinus albicaulis forest inferred 

from this subzone was different from any modern 

vegetation association. The two species at present 

overlap in their elevational distribution, but they do 

not grow together in extensive mixed forests in the 

park. Their joint occurrence suggests a slight 

lowering of vegetation associations, and a climate 

slightly cooler than at present. Both trees occur on 

drier sites, suggesting less precipitation than at 

present. This inferred cool, dry period postdates 

retreat of middle Pinedale glaciers, but its 

relationship to late Pinedale glacial advance is still 

uncertain. 

A Pinus contorta forest much like the modern one 

was present during deposition of the middle subzone 

of the Pinus contorta zone, extending from about 
E40 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

10,160 to 5,000 years ago. Picea and Abies, which now 

grow in suitable habitats at lake level, were 

apparently present only at higher elevations on the 

slopes of the Two Ocean Plateau at that time. Perhaps 

the gravelly soils near Buckbean fen accentuated the 

dry conditions and locally exterminated Picea and 

Abies. The climate was the warmest and driest of any 

inferred from the core, and this interval is correlated 

with the Altithermal period. 

Radiocarbon dates of 9,240 and 5,390 years in the 

Pinus contorta subzone are separated by less than 1 

metre of sediment (fig. 15), suggesting that a hiatus is 

present between 500 and 460 em. The dates seem 

reliable, but no break in the pollen diagram occurs in 

this interval. Macrofossils and sediment lithology 

suggest a change from a large open-lake environment 

to a small pond environment between 500 and 460 em, 

but this change could be explained without postulating 

a hiatus. A period of erosion or nondeposition 

probably occurred in this interval, but more evidence 

is needed to substantiate it. A smiliar hiatus occurred 

in the Chuska Mountains, N. Mex., during the 

Altithermal interval (Bent and Wright, 1963). 

The distribution of Picea and Abies· apparently 

expanded from the slopes of the Two Ocean Plateau 

down to lake level and they grew in mixed forests with 

Pinus contorta during the upper subzone of the Pinus 

contorta zone about 5,000 years ago. Proportions of 

Picea in these forests probably increased about 2,800 

years ago during the climax of Neoglacial activity. 

Little change in the pollen spectra can be seen during 

the last 2,800 years. Picea does not now grow at the 

coring site (elev 7,750 ft), but it grows at the same 

elevation in many areas around the Southeast Arm of 

Yellowstone Lake (fig. 6). The pollen sequence 

supports Porter and Denton's (1967) suggestion that 

post-Altithermal cooling began about 5,000 years ago. 

The pollen sequence at Cub Creek pond 

(Waddington and Wright, 1970, 1974) correlates well 

with that from Buckbean fen. The basal date of 14,360 

B.P. at Cub Creek pond (H. E. Wright, written 

commun., 1973) is about 1,000 years older than other 

dates on deglaciation in Yellowstone National Park. 

No sedimentological evidence shows contamination 

with older carbon, and the date is tentatively 

correlated with the base of Buckbean fen. Pollen 

curves in the two diagrams are remarkably similar, 

and they suggest that climatic changes triggered 

nearly synchronous changes in vegetation over large 

areas on the Yellowstone Plateau. The primary 

. zonation in the diagrams is identical and a date of 

11,630 years B.P. on the boundary between the two 

zones at Cub Creek pond corresponds well with the 

Buckbean fen date of 11,550 years B.P. just above the 

boundary. 

Zone 1 at Cub Creek pond contains relatively high 

percentages of Picea, Juniperus, Abies, Be tum, 

Gramineae, and Artemisia pollen, and low values of 

Pinus. Most of the pine in this zone is Pinus albicaulis 

type. This assemblage suggests a pollen rain identical 

to that in my Picea-Juniperus-Pinus albicaulis zone. 

The Betula and Populus subzones cannot be 

recognized at Cub Creek pond (H. E. Wright, written 

commun., 1973). 

Zone 2 at Cub Creek pond has very high Pinus 

(mainly P. contorta) pollen percentages, and low 

values of most other taxa as in my Pinus contorta 

zone. Other pollen diagrams from Yellowstone 

National Park which I have prepared (unpub. data) 

support the zonation of Buckbean fen. 

Tentative correlation of pollen sequences of Buckbean fen with those from more distant areas is 

summarized in table 6. Different vegetation, both past 

and present, in the other areas complicates correlation 

of vegetation changes, although direction of shifts may 

be related. The chart does show that the general 

climatic trend in all areas is from cold to cool to warm 

and back to cool again. 

Further work is needed to resolve several problems 

that arose during this study. I have proposed that 

sediments representing part of Altithermal time are 

missing in Buckbean fen. Pollen and plant macrofossil 

work in progress from nearby lagoons, and 

appropriate C 14 dates, may clarify the validity and 

nature of this period of erosion or nondeposition. 

Cores should be taken from other areas in the park to 

evaluate the areal extent of this hiatus. 

More precise dating of high stands of Yellowstone 

Lake may also be possible with further paleobotanical 

work and C 14 dating of cores related to each lake level, 

if sediments deposited during these stands are 

preserved in abandoned lagoons along the lake. 

Lagoons at the different levels all became open for 

lacustrine sedimentation when the lake was 110 feet 

above its present level, but lagoon isolation 

progressed from highest to lowest elevations as lake 

level fell. The horizon of isolation might be recognized 

in core sediments from lagoons formed by the lake at 

each of its major levels by a change in macrofossils of 

aquatic plants from deep- to shallow-water forms. By 

such a study the horizons could be dated by radiocarbon and the sequence worked out. 

Many plant species from arctic tundra grow on 

peaks in the Rocky Mountains far south of their 

continuous arctic distribution. Modern alpine tundra 

in the park appears to have fewer species and 
VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E41 

TABLE 6.-Tentative correlation of poUen sequences 

I Under "Inferred climate" columns, comparative climatic terms should be read from bottom upward. X= radiocarbon date; query(?)= interpretation not given 

in sources cited; solid lines (-) = separatoon of zones; dashed lines(--)= sub zones; wavy line C.rV') = hiatus(?) I 

Approx. Osgood Swamp, Swan Lake, Buckbean fen, Kirchner Marsh, Rogers Lake, 

age Sierra Nevada, Calif. southeast Idaho Yellowstone National Park southern Minnesota 

(Wright and others, 1963; southern New England 1 

<c'• (Adam, 1967) (Bright, 1966) (this paper) Watts and Winter, 1966) (adapted from Davos, 1967) 

years 

B.P. 

X 10 3 ) Inferred Inferred Inferred Inferred Zone Inferred Inferred Zone Inferred Inferred Zone Inferred Inferred Zone vegetation climate Zone vegetation climate vegetation climate vegetation climate vegetation climate 

Cooler. S-1 Sagebrush Warmer. C-3 Oak· 

steppe. chestnut. 

X X 

Sagebrush Spruce-fir· 

S-2 steppe Cooler. x<'> lodgepole Cooler, C-2 Oak· 

(treeline pine moister. hickory. 

lowered). forest. 

C-c Oak Cooler, 

4 forest. moister. 

C-1 Oak· Warmest 

X ----------- hemlock. and 

X driest(?) 

Climatic 

optimum. S-3 Sagebrush Maximum 

chenopod warmth 

steppe. and 

dryness. 

C-b Prairie. Maximum 

Lodgepole Maximum warmth. 

./V\.1' pine warmth. X 

forest. Pine· 

Maple, B birch Warmer, 

C-a basswood, Warmer, forest. drier. 

oak, elm, drier. 

forest. 

S-4 Sagebrush Increasing 

3 Mixed Cool. steppe. warmth X Conifer- Rapid A-4 Spruce Warming. 

10 X coniferous and B hardwood warming forest. 

forest. dryness. ----------- X forest. trend. 

X Lodgepole A-1, Open 

S-5 Sagebrush Warming. pine- Cool, 2, spruce Cool. 

steppe white bark drier. A-b Spruce Cool. and 3 woodland, 

with pine forest. 

Douglas- forest. 

fir. 

II S-6 Pine Cool. 

woodland. 

X 

S-7 Spruce-pine Cold, Spruce-fir· 

12 Sagebrush Cold. woodland. wet. whitebark Cool, T Tundra. Cold. 

with X pine moist. X scattered (') parkland. 

pine· ----------- A-a Spruce Cool. 

juniper(?). Parkland· forest. 

13 tundra Cold, X transition. moist. 

K Spruce Cold. 

parkland. 

1 Rogers Lake has 47 radiocarbon dates, on entire sediment column. Indovidual dates not shown. 2 Pinus contorta. 3 Picea-Juniperus-Pinus albicaulis. 

community types than tundra of the Beartooth 

Plateau, Mont., to the north or that of the Wind River 

Range, Wyo., and the Front Range, Colo., to the 

south. The few late-glacial fossils of arctic-alpine 

plants from Lilypad pond indicate that these plants 

grew about 2,000 feet lower than they grow today. 

These fossils support the theory that during glacial 

periods, when treelines were lower, areas like the 

park may have been routes of southward migration for 

arctic species. When treelines rose in postglacial time, 

alpine species became isolated on high peaks and were 

eliminated in areas of lower elevation. Additional 

detailed pollen and plant-macrofossil studies are 

needed to determine areal and elevational distribution 

and composition of late-glacial tundra vegetation. 

REFERENCES CITED 

Adam, D.P., 1967, Late Pleistocene and Recent _palynology in the 

central Sierra Nevada, California, in Quaternary paleoecology-Internat. Assoc. Quaternary Research, 7th Cong., 

1965, Proc., v. 7: New Haven, Conn., Yale Univ. Press, p. 275-301. 

American Commission on Stratigraphic Nomenclature, 1961, Code 

of stratigraphic nomenclature: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 5, p. 645 - 665. 
E42 GEOLOGY OF YELLOWSTONE NATIONAL PARK 

Antevs, Ernst, 1955, Geologic-climatic dating in the West: Am. 

Antiquity, v. 20, no. 4, p. 317-335. 

Baker, F. S., 1944, Mountain climates of the western United 

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VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN E43 

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Geol. Soc. America Bull., v. 74, no. 11 p. 1371-1396. 

A Page 

Abies...... .E17,25, 26,31,38 

lasiocarpa ............ ........ 7, 12, 25, 26,36 

Abies forest, Pinus contorta-Picea- . . . 17 

Abies lasiocarpa- Pinus albicaulis parkland, 

Pice"' engelmannii- . . . . . . . . 25 

AbieP parkland, Picea.................. 17 

AbieP-Pinus albicaulis forests, Picea- . . 4,12 17, 18, 39 

Abies-Pinus albicaulis- parklands, Picea- . . . 17, 18 

Abies-Pinus albicaulis-Pinus contorta 

forest, Picea- . . . . . . . . . . 17 

Abies-Pinus contorta subzone, Picea-...... 38 

Absaroka Range. . . . . . . . . . . . . . . . . . . . . . . . 5, 10, 12 

Abstract . . . . . . . . . . . . . . . 1 

Acer. 7, 27 

negundo. 27 

Aceraceae . . . . 7 

Achillea lanulosa 8, 10 

Aconitum columbianum 9, 12 

acutus, Scirpus......................... 9, 17 

adenocaulon, EpiWbium.... . . . . . .8, 28; pl. 8 

Age, Altithermal ..................... 5, 25, 39, 40 

Bull Lake Glaciation. . . . . . . . . . . . . . . . . 5 

Gannett Peak Stade. . . . . . . . . . . . . . . . . 5, 25, 38 

Hypsithermal interval. . . . . . . . . . . . . . . 6 

Neoglaciation . . . . . . . . 5 

Pinedale Glaciation . . . . . . . . . . . . . . . . . 4, 5 

late stade . . . . . . . . . . . . . . . . . . . . . . 25, 37, 39 

middle stade ................ 25, 31, 35, 39 

Post-Altithermal . . . . . . . . . . . . . . . . . . . 40 

Temple Lake Stade . 5, 25, 38 

Agropyron. . . . . . 9, 10 

· albicaulis, Pinus . ...... 7, 12, 17, 25, 26, 34, 36, 37, 38; 

pis. 1. 5 

Adler, thinleaf . . . 7, 37 

western........................... 28 

Algae................................. 30 

Alnus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26, 37 

tenuifolia. . . . . . . . . . . . . . . . . . . . .. 7. 28, 37; pl. 6 

Alpine association . . . . . . . . . . . . . . . . . . . . 12, 41 

Alpine sorrel . . . . . . . . . . . . . . . . . . 9, 36 

A I pine tundra . . . . . . . . . . . . . . . . . . . . . . . . . 40 

alpinus, Potamogeton .. . 10, 14, 17, 25, 30, 32, 36; pl. 7 

Altithermal period ........... 5, 25, 39, 40 

Amaranthaceae . . . . . . . . . . . . . . . . . . . . . . . . 7 

Ambrosia . . . . . . . . . . . .... 8, 26, 28, 36; pl. 2 

americanum, Arceuthobium.............. 8, 28,37 

amphibia, Persicaria . . . . . . . . . . . . . . . . . . . . 9, 14, 17 

amphibium, Polygonum . . . . . . . . . . . . . . . . . 9 

Analysis method, cores . . . . . . . . . . . . . . . . . . 20 

pollen............................. 16 

Anemone, globose . . . . . . . . . . . . . . . . . . . . . . 9, 15 

Anemone multifida . . . . . . . . . . . . . . . . . . . . . 15 

globosa............................ 9 

angustifolia, Typha . . . . . . . . . . . . . . . . . . . . . 10, 30 

angustifolium, Sparganium . . . . . . . . . . . . . . 10, 30 

Antennaria . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 10 

aquatilis, Carex . . . . .. 9, 14, 17, 29, 38; pl. 9 

Ranunculus .................. 9, 20, 32, 36; pl. 8 

Arabis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 12 

glabra............................. 8, 10 

Arceuthobium ...................... . 8, 26, 37; pl. 2 

americanum . . . . . . . . . . . . . . . . . . . . . . . 8, 28,37 

campylopodum..................... 8, 28 

douglasii . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 28, 37 

Arctic-alpine plants, Lilypad pond . . . . . . . . 41 

Arctic burreed . . . . . . . . . . . . . . . . . . . . . . . 10 

Arctic willow . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

INDEX 

[Page numbers of major references are in italic] 

Page 

arctica, Salix. . . . . . . . . . . . . . . . . . . . . . . . . . . E9, 12 

Arctostaphylos uva-ursi................ 8, 10, 12 

argenteus, Lupinus . . . . . . . . . . . . . . . 8, 10, 12 

Artemisia. . ................... 8, 26, 31, 32 

tridentata......... . ...... 8,10, 16, 17,19 

Artemisia pollen percentages 19 

Artemisw steppe association ............ 10, 13, 17 

pollen . . . . . . . . . . . . . . . . . . . . . . . . . . 16 

Artemisia tridentata steppe, Gramineae-.. 17 

Ash. . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Aspen, quaking ......... . 

Aster ............. . 

A triplex sp. 

Aulacomnium palustre 

Aulacomniaceae .... 

Avens,large-leaf .. 

B 

9, 10, 12 

8,15 

8,10 

7,15 

7 

9,15 

Balsam poplar . . . . . . . . . . . . . . . . . 9, 34 

balsamifera, Populus .. ...... 9, 25, 29, 34, 35, 36; pl. 6 

Basal zone . 30 

Bearberry . . . . . . . . 8 

Beartooth Plateau, Mont. . . . . . . . . . . . . . . . . 12, 29, 41 

Bechler River Ranger Station . . 2 

Bedstraw, small . . . . . . . 9, 14 

Betula. . . . . . . . . . . . . . . . . . . . . . . . 8, 26, 27 

glandulosa ....... ..... 8, 25, 28, 31, 33, 36; pl. 6 

occidentalis . . . . . . . . . . . . . . . . . . . . . . . . 8, 28 

Betula subzone . . . . . . . . . . . . . . . . . . . . . . . . 31, 39 

Betulaceae. . . . . . . . . . . . . . . . . . . . . . . . 7, 8, 27 

biennis, Potentilln . 9, 29, 36; pl. 8 

Big sagebrush . . . . . . . . . . . . 8, 10 

Birch...... 8, 28 

bog... 8, 31 

river. 8 

Bistort . . . . . . . . . . . . . . . . . . . . . . . 9, 12 

VIVIparous . . . . . . . . . . . . . . . . . . . . . . . . . 9, 12 

Bistorta ......................... ~. 19, 27, 33; pl. 3 

bistortaides . . . . . . . . . . . . . . . . . . . . . . . . 9, 12, 28 

vivipara . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 12, 28 

bistortaides, Bistorta . . . . . . . . . . . . . . . . . . . 9, 12, 28 

Polygonum . . . . . . . . . . . . . . . . . . . . . . . . 9 

Black cottonwood....................... 9, 36 

Bladderwort, common. . . . . . . . . . . . . . . . . . . 8, 14 

small.............................. 8,14 

blandowii, Helodium . . . . . . . . . . . . . . . . . . . . 7, 15 

Blue spruce . . . . . . . . . . . . . . . . . . . . . . . . . . 16 

Blue willow............................. 9,14 

Bluebell . . . . . . . . . . . . . . . . . . . 8, 12 

Blueberry. myrtle .. .. .. .. .. .. .. .. .. .. .. 8, 12 

Bluegrass. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Blue joint grass . . . . . . . . . . . . . . . . . . . . . . . . . 9, 15 

Bog birch.............................. 8, 31 

Boraginaceae . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

borealis, Glyceria. . . . . . . . . . . . . . . . . . . . . . . 9, 30 

Broadleaf cattail. . . . . . . . . . . . . . . . . . . . . . . . 10, 33 

Brome, smooth . . . . . . . . . . . . . . . . . . . . . . . . . 9 

Bromegrass.. . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 10 

Bromus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 17 

inermis. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 10 

~-· 1~ffi 

Bryophyta . . . . . . . . . . . . . . . . 27 

Bryophyte spore. . . . . . . . . . . . . . . . . . . . . . . . pl. 1 

Bryozoa. . . . . . . . . . . . . . . . . . 30 

Buckbean fen .... 3, 8, 14, 15, 20, 24, 27, 28,31, 39, 40 

basal zone 31 

dates. · 7 

Buffaloberry . . . . . 8, 12 

Bull Lake Glaciation .. 

Burreed. 

Arctic ..... . 

Bushy knot weed ....................... . 

c 

Page 

E5 

10,33 

10 

9 

caespitosa, Deschampsia . . . . . . . . . . . . . . . . 9, 15 

Saxifraga. . . . . . . . . ... 9, 12, 29, 33; pl. 10 

Calamagrostis canadensis. . . . . . . . . . . . . . . . 9, 15, 30 

inexpansa . . . . . . . . . . . . . . . . . . . . . . . . . 9, 15, 30 

Calamagrostis-Salix-Sedum rhodanthum 

community 15, 17 

californica, Descurainia .............. . 8, 28, 31; pl. 8 

Callitrichaceae . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Callitriche . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 17 

Campanula rotundifolia. . . . . . . . . . . . . . . . . . 8, 10 

Campanulaceae. . . . . . . . . . . . . . . . . . . . . . . . . 8 

campylopodum, Arceuthobium . . . . . . . . . . . 8, 28 

canadensis, Calamagrostis . . . . . . . . . . . . . . . 9, 15, 30 

Shepherdia . . . . . . . . . . . . . . . . . . . . . . . . 8, 12, 17 

canescens, Carex . . . . . 9, 15, 29, 39; pl. 9 

Caprifoliaceae . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 27 

Carex ................................. 17, 29, 37 

aquati/;is.. .9,14,17, 29, 38; pl. 9 

canescens . . . . . . . 9, 15, 29, 39; pl. 9 

diandra . . . 9, 14, 25, 30, 38; pl. 9 

geyeri. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 12 

hoodii . . . . . . . . . . . . . . . . . . . . . . . . 9, 10 

limosa. . ........ 9, 14, 25, 30, 38; pl. 7 

petasta............................ 10 

phaeocephala . . . . . . . . . . . . . . . . . . . . . . 9, 15 

rostrata........................... 9 

trigonous . . . . . . . . . . . . . . . . . . . . . . . . . . 38 

utriculata ....... 9,14,15,17, 25, 30, 37, 38; pl. 7 

vesicaria . . . ..... 9, 17, 25, 30, 38; pl. 7 

Carexdiandra-Potentillnpalustris fen . . . . 14,17 

Carex fen 17 

Carex- Gramineae meadow............... 17 

Carex utriculata fen . . . . . . . . . . . . . . . . . . . . 14, 17 

Caryophyllaceae. . . . . . . . . . . . . . . . . . . . . . . . 8, 27 

Cattail, broadleaf. . . . . . . . . . . . . . . . . . . . . . . 10, 33 

narrowleafed . . . . . . . . . . . . . . . . . . . . . . . 10 

Ceanothus velutinus . . . . . . . . . . . . . . . . . . . . 9, 17, 27 

Ceratopyllaceae . . . . . . . . . . . . . . . . . . . . . . . . 8 

CeratophyUum demersum . . . . . . . . . . . . . . . 8, 37 

Cercocarpus . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 26 

Chara................................. 7 

Characeae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Charophytes . . . . . . . . . . . . . . . . . . . . . . . . . . . 30,31 

Cheno-Ams . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 16, 32 

Chenopodiaceae . . . . . . . . . . . . . . . . . . . . . . . . 8 

Chenopodiaceae -Amaranthaceae . . . . . . . . . 8, 16, 26 

Chiming bells . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Chrysothamnus . . . . . . . . . . . . . . . . . . . . . . . . 8, 10, 17 

Cinquefoil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

marsh............................. 9,14 

Norway........................... 9 

shrubby . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 15 

soft............................... 9 

Climacium dendraides . . . . . .. . . .. .. . . . . . . 7, 15 

Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

cooler moister . . . . . . . . . . . . . . . . . . . . . . 39 

warmest........................... 40 

Colorado blue spruce . . . . . . . . . . . . . . . . . . . . 7 

columbianum, Aconitum. . . . . . . . . . . . . . . . . 9, 12 

Common bladderwort . . . . . . . . . . . . . . . . . . . 8, 14 

Common harebell . . . . . . . . . . . . . . . . . . . . . . . 8 

Common juniper . . . . . . . . . . . . . . . . . . . . . . . 7 

E45 
E46 

Page 

Common phlox . . . . . . . . . . . . . . . . . E9, 10 

communis, Juniperus . 7, 12, 17, 25, 26, 31, 36; pl. 5 

Compositae.. . ......... 8, 20, 26, 28, 31; pl. 2 

Conifer needles . . . . . . pl. 5 

contorta, Pinus ... 7, 12, 16, 17, 26, 27, 37, 38; pis. 1, 5 

Cores . . 2, 13 

analysis method . . . . . . . . . . . . . . . . . . . 20 

Cottongrass. . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 15 

Cottonwood, black. . . . . . . . . . . . . . . . . . . . . 9, 36 

Crassulaceae . . . . . . . . . . . . . . . . . . . 8, 28 

Crowfoot, water.. . . . . . . . . . . . . . . 9, 33 

Cruciferae.. . . . . . . . . . . . . 8, 27, 28 

Cub Creek core. . . . . . . . . . . . . . . . 15 

Cub Creek pond. . ......... 23, 91, 39,40 

basal zone . . . . . . . . . . . . . . . 31 

Cupressaceae . . . . . . . . . . . . . . . . . . 7 

Cyperaceae . . . ......... 9, 12, 17, 27, 29, 38 

D 

demersum, CeratophyUum. . . . . . . 8, 37 

dendroides, Climacium . . . . . . . . . . 7, 15 

densa, SelagtneUa . . . 7, 12, 19, 24, 27; pl. 1 

Deschampsia caespitosa . . . . . . . . . . . . . . . . . 9, 15 

Descurainiacalifornica .8, 28, 31; pl. 8 

Diamond leaf saxifrage . . . . . . . . . . . . . . . . . . 9, 12 

diandra, Carex . . . . . 9, 14, 25, 30, 38; pl. 9 

Diatoms... . . . . . . . . . . . . . . . . 30, 31 

Dock.. . . . . . . . . . . . . . . . . 9 

golden . . . . . . . . . . . . 9 

willow............................. 9 

Douglas-fir . . . . . . . . . . . . . . . . . 7, 10 

Douglas-fir dwarf mistletoe . . . . . . . . . . . 8 

douglasii, Arceuthobium................. 8, 28, 37 

Drepanocladus . . . . . . . . . . . . . . . . . 7 

sp.... 14, 15 

Dwarf mistletoe . . . . . . . . . . . . . . . 37 

Eleagnaceae .......... . 

Eleocharis macrostachya 

Elephantella ......... . 

Elymus .. 

empetriformis, PhyUodoce 

Engelmann spruce .. 

engelmannii, Picea 

Ephedra torreyana 

viridis .. 

E 

8 

.9, 17, 30; pl. 9 

9, 15 

9, 10, 17 

8, 17 

7,12 

. 7' 12, 16, 25, 26, 36; pl. 5 

7, 26 

Ephedraceae . . ......... . 

7, 26; pl. 1 

7 

. 8, 28; pl. 8 

.8, 28, 38; pl. 8 

Epilobium adenocaulon .. 

glandulosum . 

lactiflorum . 

Equisetaceae ... 

Equisetum. 

Ericaceae .. 

Eriogonum 

Eriophorum . . 

subalpinum .... 

. .8, 28, 36; pl. 8 

7 

7, 27 

8 

.9, 27 

9 

10, 12 

sp... . ............ . 14 

excalbescens, MyriophyUum spicatum 8, 28 

F 

Fagaceae........ . . . . . . . . . . . . 8 

Fen....... . . . . . . . . . . . . . . . . . 38 

Buckbean . 3, 7, 8, 14, 15, 20, 24, 27, 28, 91, 39, 40 

Carex... . . . . . . . . . . . . . . . . . . . . . . 17 

diandra-PotentiUapalustris. 14, 17 

utriculata 14, 17 

Fen types . . . 14 

Fern.. . . . . . . . . . . . . . . 7 

filiformis, Potamogeton .......... 10, 25, 30, 32; pl. 7 

Fir, Douglas . . . . . . . . . . . . . . 7, 10 

subalpine . . . . . . . . . . . . . . . . . 7, 12 

Fires, history . . . . . . . . . . . . . . . 12 

Pinus contorta . . . . . . . . . . . . . . . . . . . . 38 

flexilis, Naias .10, 25, 30, 36, 37; pl. 9 

Ptnus ............................ 7, 10, 17, 26 

INDEX 

Page 

floribunda, PentaphyUoides... . E9, 15, 17 

Forest, fires . . . . . . . . . . . . . . . 34 

open, mixed. 37 

Picea-Abies-Pinus albicaulis . .... 4, 12, 17, 18, 39 

Picea-Abies-Pinus albicaulis-· Pinus contorta . . . . 17 

Pinus albicaulis-Pinus contorta . . . . . . . 25 

Pinus contorta .......... 4, 12, 17, 18, 25, 37,39 

closed . . . . . . . . . . . . . . . . . 25 

open . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Pinus contorta- Picea-Abies . . 17 

Pinus contorta-Ptnus albicaulis . . . . . . . . 39 

Populus tremuWUJ.es-Pseudotsuga . . . . 17 

Pseudotsuga 18 

Fragaria. . . . . . . . . . . . . . . 9 

Franseria. . . . . . . . . . . . . . . . . . 8, 28 

Fraxinus . . 8, 27 

Front Range, Colo. . . . . . . . . . . . . . . . . . . . . 41 

fruticosa, PotentiUa . . . . . . . . . . . . . . . . . . 9 

fueginus, Rumex .................... 9, 29, 37; pl. 6 

maritimus . . . . . . . . . . . . . . . . 9 

Further work . . . . . . 40 

G 

Galium trifidum . . . . . ............ . 

Gannett Peak end moraines ....... . 

Gannett Peak Stade . . . . ......... . 

Gentian, Rocky Mountain fringed . . . . . . . . 

Gentiana thermalis ..... 

9, 14, 15 

5, 25,38 

5, 25,38 

8,15 

8 

Gentianaceae . . . . . . . . . . . . . . . . . . . . . . 8 

Gentianopsis thermalis 8, 15 

Geum macrophyUum . . . . . . . . . . . . . 9, 15 

geyeri, Carex . . . . . . . . . . . . . . . . 9, 12 

glabra, Arabis.............. 8, 10 

Glacial history. . . . . . . . . . . . . . . . . . . . . . . . . 5 

Glacier Peak . . . . . . . . . . . . . . . 31 

glandulosa, Betula ........ . 8, 25, 28, 31, 33, 36; pl. 6 

glandulosum, Epilobium. . . 8, 28, 38; pl. 8 

Ledum . . . . . . . . . . . . . . . . 8, 17 

globosa, Anemone multifida. . . . . . . . 9 

Globose anemone . . . . . . . . . . . . . . . . 9, 15 

Glyceria borealis . . . . . 9, 30 

grandis......... 10 

maxima grandis . . .. 10, 30, 37; pl. 9 

Golden dock 9 

gracilis, PotentiUa. . . . . 9, 20, 31, 36; pl. 8 

Gramineae.. . .9, 12, 17, 20, 27, 90,31 

Gramineae-Artemisia tridentata steppe. . . 17 

Gramineae meadow, Carex- . . . . . . . . . . . . 17 

Gramineae/Pinus ratio.... . ...... 20, 34, 36, 37 

gramineus, Potamogeton.... . .10, 25, 30, 37; pl. 7 

grandis, Glyceria . 10 

Glyceria maxima. . . . . . . . ... 10, 30, 37; pi 9 

Grass, blue- 10 

bluejoint-........ 9, 15 

Brome-. . . . . . . . . . . . . . . . . . . 9, 10 

large manna- . . . . . . . . . . . . . . . . . . . . . . . 10, 37 

needle-............................ 10 

northern manna- 9 

northern reed- .... . 

smooth brome ..................... . 

squirrel-tail. 

tufted hair- .. 

wheat- ..... . 

wild-rye .. . 

Grass family .. 

Greasewood 

Green jointfir 

Greenmilfoil ....................... . 

groenlandica, Pedicularis ............... . 

Grouse Creek . . ............... . 

H 

Hairgrass, tufted ...................... . 

Haloragaceae . . . . ........ . 

Harebell, common . . . . . . . . . . . . . . . . . . . . . 

Helodium blando-wii .................... . 

Hemlock, mountain .................... . 

9,15 

9 

10 

9, 15 

9,10 

9 

12 

8, 10, 16 

7 

8 

9,15 

5 

9, 15 

8, 28 

8,10 

7, 15 

7 

Hemlock-Continued 

western ........................ . 

heterophyUa, Tsuga... . ........... . 

Honeysuckle family . . .......... . 

hoodii, Carex . ......................... . 

Hornwort .............. . 

Horsetail ............................ . 

Hydrodictyaceae ...................... . 

Hydrophyllaceae ...................... . 

Hypnaceae............ . ............. . 

Hypsithermal interval. ................. . 

hystrix, Sitanion .............. . 

I, J 

Page 

E7 

7, 27 

8 

9,10 

8, 37 

7 

7 

8 

7 

6 

10 

illinoensis, Potamogeton................ 10, 30 

tnermis, Bromus........................ 9, 10 

inexpansa, Calamagrostis. . . . . . . . . . . 9, 15, 30 

integrifolium, Sedum rosea . . . . . . . . . . . 8 

Isoetaceae . . . . . . . . . . . . . . . . . . . . . . . 7 

Isoetes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 17 

islandica, Koenigia. . . . . . . . . ..... 9, 36; pl. 3 

Rorippa ...................... 8, 28, 36; pl. 10 

Jacobs ladder . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 12 

Jointfir, green . . . . . . . . . . . . . . . . . . 7 

Juglandaceae . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Juglans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 27 

Juncaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 12 

Juniper, common . . . . . . . . . . . . . . . . . . . . . . . 7 

Rocky Mountain . . . . . . . . . . . . . . 7, 10 

Ju"!iperus ......................... 7, 26, 31; pl. 1 

communis .......... 7, 12, 17, 25, 26, 31, 36; pl. 5 

virginiana scopulorum . . . . . . . . . ... 7, 10, 17, 26 

Juniperus-Pinus albicaulis zone, Picea-.. 30, 99 

Kalmia polifolia . . 

Kame deposits 

Kings Crown ... 

K,L 

8,17 

7 

8 

Kinnikinnik . . . 8, 10 

Knotweed, bushy . . . . . . . . . . . . . . . . . . . . . . . 9 

Koenigia . . . . . . . . . . . . . . . . . . . . 27, 28 

islandica. . . . . .................... 9, 36; pl. 3 

lactiflorum, Epilobium . . . . . . . ...... 8, 28, 36; pl. 8 

Ladysthumb . 9 

Lamar Ranger Station. . . . . . . . . . . . . . . . . . . 2 

lanceolatum, Sedum . . . . . . . . . . . . 8 

lanulosa, Achillea . . . . . . . . . . . . . . 8, 10 

Large-leaf avens. . . . . . . . . . . . . 9, 15 

mannagrass. . . . . . . . . . . . . . . . . . . . 10, 37 

Larix lyaUii . . . . . . . . . . . . . . . . . . . . . . . . . . 24 

occidentalis . . . . . . . . . . . . . . . . . . . . . . . . 24 

lasiocarpa, Abies. . . . .......... 7, 12, 25, 26, 36 

latifolia, Typha ................. . 10, 27, 30, 33; pl. 2 

Ledum glandulosum . . . . . . . . . . . . . . . . . . 8, 17 

Leguminosae. 8, 27 

Lentibulariaceae . . . . . . . . . . . . . . . . . . . . . . . 8 

Leskeaceae . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Liguliflorae, subfamily..... . ...... 8, 26, 28, 31 

ligulifolia, Salix............... 9, 14, 15 

Lily, yellow pond . . . . . . . . . . . . . 8 

Lilypad pond .................. 3, 15, 20, 28, 31,41 

basal zone . . . . . . . . . . . . . . . 31 

dates......... . . . . . . . . . . . . . . . . 7 

Limber pine. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 10 

limosa, Carex. . ........... 9, 14, 25, 30, 38; pl. 7 

Lodgepole pine . . . . . . . . . . . . . . . . . . . . . . . 7, 12 

Lodgepole pine dwarf mistletoe . . . . . . . . . . 8, 37 

longifolium, Sitanion . . . . . . . . . . . . . . . . . . . . 10 

Loranthaceae . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 28 

Lupine, silvery . . . . . . . . . . . . . . . . . . . . . . . . . 8, 10 

Lupinus argenteus . . . . . . . . . . . . . . . . 8, 10, 12 

luteum polysepalum, Nuphar ........ 8, 14, 25, 28, 37, 

Luzula parviflora .............. . 

spicata 

lyaUt"i, Larix 

38; pl. 7 

10, 12, 15 

10, 15 

24 
M Page 

Macrofossils, identification. . . . . . . . . . . . . . . E20 

macrophyUum, Geum . . . . . . . . . . . . . . . . 9, 15 

macrostachya, Eleocharis. . . . . . . 9, 17, 30; pl. 9 

maculata, Persicara . . . . . . . . . . . . . . . . . 9 

Mahogany, mountain.......... 9 

Mammoth . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

climate........................ 2 

Mannagrass, large . . . . . . . . . . . . . . . . . . . . . . 10, 37 

northern . . . . . . . . . . . . . . . . . . 9 

Maple.. . . . . . . . . . . . . . . . . . . 7 

maritimus fueginus, Rumex . . 9 

Marsh cinquefoil. . . . . 9, 14 

Marshcress . 8, 36 

Matted saxifrage . . . 9, 12 

maxima grandis, Glyceria ........... . 10, 30, 37; pl. 9 

Meadow, Carex-Gramineae.............. 17 

Meadow rue . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

Melosira. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Menyanthaceae . . . . . . . . . . . . . . . . . . . . . . . 8, 28 

Menyanthes . . . . . . . . . . . . . . . . . . . . . . . . . . . 27; pl. 3 

trifoliata .............. 8, 14, 15, 25, 28, 38; pl. 6 

menzieii, Pseudntsuga ...... 7, 10, 24, 25, 37, 38; pl. 5 

Mertensia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 12 

mertensiana, Tsuga . . . ................ 7, 27; pl. 1 

Middle Pinedale glaciers . . . . . . . . . 39 

Mimulus . . . . . . . . . . . . . . . 9; pl. 2 

minimum, Sparganium............ 10,30 

minor, Utricularia . . . . . . . . . . . . . . . . . 8, 14 

Mistletoe, Douglas-fir dwarf . . . . . . . . 8 

dwarf........................... 97 

lodgepole pine dwarf . . . . . . . . . . . . . . . . 8, 37 

western dwarf . . . . . . . . . . . . . . . . 8 

Monkey flower . . . . . . . . . . . . . . . . . . 9 

Monkshood . . 9, 12 

Mosses. . . . . . . . . . . . 7, 17 

Mount Evans fire . . . . . . . . . . . . . . 34 

Mountain hemlock . . . . . . . . . . . . . 7 

Mountain mahogany 9 

Mountainheath 8 

multiflora, Phlox . . . . . . . . . . . . . . 9, 10 

multi.fida globosa, Anemone.............. 9 

MyriophyUum .......... ........ 8, 17, 27,37; pl. 2 

spicatum exalbescens . . . . . . . . . . . . . 8, 28 

verticiUatum... 8, 28 

sp..................... 25,37 

myrtiUus, Vaccinium....... 8, 12 

Myrtle blueberry . . . . . . . . . . . . . . . 8, 12 

N 

Naiad . . . . . . . . . . . . . . . 10, 36 

Naiadaceae . . . . . . .. . . . . . . . . . . . . . . . . . 10, 90 

Naiasjlexilis. . ........... 10, 25, 30, 36, 37; pl. 9 

Narrowleafed cattail·. . . . . . . . . . . . . . . . . . . . 10 

Needle, conifer . . . . . . . . . . . . . . . . . . . . . . . . . pl. 5 

Needle' distribution . . . . . . . . . . . . . . . . . . . . 34 

Needlegrass . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

negundn, Acer . . . . . . . . . . . . . . . . . 27 

Neoglaciation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

~~... ··············· 9 Northern mannagrass . . . 9 

Northern pondweed . . . 10, 14 

Northern reed grass. . . . . . . . . . . . 9, 15 

norvegica, PontentiUa. 9, 29 

Norway cinquefoil . . . 9 

Nuphar . . . . . 17, 27, 37; pl. 2 

luteum polysepalum . ........... 8, 14, 25, 28, 37 

Nuphm:-Potamogeton type ....... . 

Nymphaeaceae .................. . 

O,P 

Oak 

occidentalis, Betula . 

Oleaceae ..... . 

38; pl. 7 

14 

8,28 

8 

8, 28 

8 

Onagraceae . . . . . . 8, 27, 28 

Oxyria ................ ........ 9, 27, 28, 36; pl. 4 

INDEX 

Page 

Pale willow-herb . . . . . . . . . . . . . . . . . . . . . . . E8, 36 

palustre,Aulacomnium.................. 7,15 

palustris, PotentiUa . . 9, 14, 25, 27, 29, 30; pis. 4, 8 

Parklands . . . . . . . . . . . . . . . . . . . . . . . . 18, 37 

Picea-Abies.... . . . . . . . . . . . . . . . 17 

Pinus albicaulis . . . . . . . . . . . . . . . . 17, 18 

Picea engelmannii-Abies lasiocarpaPinus albicaulis . 25 

Pinus albicaulis-Picea . . . . . 17 

parviflora, Luzula . . . . . . . . . . . . . . . . . . . 10, 12, 15 

paucifolius, Rumex . . . . . . . . . . . . . . . . . . . . . 9 

pectinatus, Potamogeton . . . . . . . . . . . . . . . . 10, 30 

Pediastrum. . . . . . . . . . . ..... 7, 27, 31, 38, 39; pl. 4 

Pediastrum colonies . . . . . . . . . . . . 30 

Pedicularis . . . . . . . . 9, 27 

groenlandica . . . . . . . . . . . . 9, 15 

PentaphyUoidesfloribunda... 9, 15, 17 

Persicara maculata . . . . . . . . . . . . . . . . . . . 9 

Persicariaamphibta..... 9, 14, 17 

persicaria, Polygonum . . . 9, 27, 28 

Phacelia . . . . . . . . 8, 10 

phaeocephala,Carex . . . . . . . . . . . . . . . . . . . 9, 15 

Phlox, common . . . . . . . . . . . . . . . . . . . . . . . . . 9, 10 

Phlox multiflora ................ :....... 9, 10 

PhyUodoce empetriformis................ 8, 17 

Picea .................... . 17, 25, 26, 31, 34, 38; pl. 1 

engelmannii ........... 7, 12, 16, 25, 26, 36; pl. 5 

pungens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 16 

Picea-Abies forest, Pinus contorta- . . . . . . . 17 

Picea-Abies ."parkland . . . . . . . . . . . . . . . . . . . 17 

Picea-Abies,P,nus albicaulis forests .. 4, 12, 17, 39 

pollen.... 18 

Picea-Abies- Pinus albicaulis parklands . . . 17, 18 

Picea-Abies -Pinus albicaulis-Pinus contorta 

forest .................... . 

Picea-Abies~Pinus contorta subzone ...... . 

Picea engelmannii-Abies lasiocarpa-Pinus 

17 

25,98 

albicaulis parkland . . . . . . . . 25 

Picea-Juniperus-Pinus albicaulis zone ..... 25, 90, 39 

Picea parkland, Pinus albicaulis- . . . . . . . . . 17 

Piceol Ptnus ratio 1 • • • • • • • • • • • • • • 20 

Pinaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 24 

Pine, limber . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 10 

lodgepole . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 12 

ponderosa . . . . . . . . . . . . . . . . . . . . . . . . . 7, 10 

whitebark . . . . . . . . . 7, 12 

Pinedale Glaciation ........... 4, 5, 25, 31, 35, 37,39 

Ptnus albicaulis ......... 7, 12, 17, 25, 26, 34, 36, 37, 

38; pis. 1,5 

Pinus albicaulis forest, Pinus contorta- . 39 

Pinus albicaulis forests. Picea-Abies- 4,12, 17, 18, 39 

Pinus albicaulis parklands, Picea-Abies- . . . 17, 18 

Picea engelmannii- Abies lasiocarpa- 25 

Pinus albicaulis-Picea parkland . . . . . . . . . . . 17 

Pinus albicaulis-Pinus contorta forest . . . . . . 25 

Picea-Abies- ...................... · · 17 

Pinus albicaulis!Pinus contorta ratio .. 20, 31, 34, 36, 

37,38 

Pinus albicaulis zone, Picea-Juniperus- . . 30, 99 

Pinuscontorta ... . 7,12,16,17,26, 27, 37,38; pls.1,5 

Pinus contorta forests ............. 4, 12, 17, 25, 39 

po~n .............. ·············· ~ 

Picea-Abies-Pinus albicaulis 17 

Pinus contorta-Picea-Abies forest" .. ·····. 17 

Pinus contorta-Pinus albicatLlis forest . . . . 39 

Pinus contorta-Pinus albicaulis subzone . . . 97 

Pinus contorta subzone . . . . . . . . . . . . . . . 97 

hiatus............. 40 

Picea-Abies- . . . . . 38 

Ptnus contorta zone 96, 39 

Pinusflexilis . . . . . . 7, 10, 17, 26 

ponderosa . . . . . . . . . . . . . . . . . . . . . . . . . 7, 10 

Pinus pollen curve . . . . . . . . . . . . . . . . . . . . . 22 

Plantago . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 27 

Plantain............................... 9 

Plataginaceae . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

Poa................................... 10 

Polemoniaceae . . . . . . . . . . . . . . . . . . . . . . 9, 28 

Polemonium . . . . . . . . . . .... 9, 12, 27, 28, 33; pl. 3 

polijolia, Kalmia . . 8, 17 

E47 

Page 

Pollen, analysis method . . . . . . . . . . . . . . . . . E16 

Artemisia steppe . . . . . . . . . . . . . . . . . . . 16 

Picea-Abies-Pinus albicaulis forests . . . 18 

Picea-Abies-Pinus albicaulis parklands 18 

Pinus contorta forests . . . . . . . . . . . . . . . 18 

Pseudotsuga forest . . . . . . . . . . . . . . . . . 18 

Pollen curves . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

Pollen inderitification. . . . . . . . . . . . . . . . . . . . 20 

Pollen rain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Pollen ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Pollen samples, other . . . . . . . . . . . . . . . . . . . 15 

Polygonaceae . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 28 

Polygonum . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

amphibium . . . . . . . . . . . . . . . . . . . . . . . . 9 

bistortoides . . . . . . . . . . . . . . . . . . . . . . . . 9 

persicaria. . . . . . . . . . . . . . . . . . . . . . . . . . 9, 27, 28 

ramosissimum...................... 9, 27,28 

viviparum . . . . . . . . . . . . . . . . . . . . . . . . . 9 

Polypodiaceae . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 27 

polysepalum, Nuphar luteum . . . . . . 8, 14, 25, 28, 37, 

38; pl. 7 

Pond, warm water . . . . . . . . . . . . . . . . . . . . . . 37 

Ponderosa pine . . . . . . . . . . . . . . . . . . . . . . . . . 7, 10 

ponderosa, Pinus . . . . . . . . . . . . . . . . . . . . . . . 7, 10 

Pondweed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

northern . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 14 

sago . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Poplar, balsam . . . . . . . . . . . . . . . . . . . 9, 34 

Populus . . . . . . ............ 9, 26, 34; pl. 4 

balsamifera . ........... 9, 25, 29, 34, 35, 36; pl. 6 

tremuloides. . . . . . . . . . . . . . . . . . . . . . . 9, 10, 12 

trichocarpa . . . . . . . . . . . . . . . . . . . . . . . . 9, 29. 36 

Populus subzone ....................... _. 25, 95, 39 

Populus tremuloides· Pseudotsuga forest . . 17 

Post-Altithermal cooling. . . . . . . . . . . . . . . . . 40 

Potamogeton ........................... 17, 27,38 

alpinus ........... 10, 14, 17, 25, 30, 32, 36; pl. 7 

filijormis ................... 10, 25, 30, 32; pl. 7 

gramineus ................. . 10, 25, 30, 37; pl. 7 

iUinoensis. . . . . . . . . . . . . . . . . . . . . . . . . . 10, 30 

pectinatus . . . . . . . . . . . . . . . . . . . . . . . . . 10, 30 

vaginatus. . . . . . . . . . . . . . . . . . . . 10, 30 

~········ ····················· u 

PotentiUa biennis. . ............ 9, 29, 36; pl. 8 

fruticosa. . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

gracilis . ..................... 9, 20, 31, 36; pl. 8 

norvegica. . . . . . . . . . . . . . . . . . . . . . . . . . 9, 29 

palustris .......... 9, 14, 25, 27, 29, 30; pis. 4, 8 

~········· .................. U,M 

PotentiUa palustris fen, Carex diandra- 14, 17 

procumbens, Sibbaldia . . . . . . . . . . . . . . 9, 29, M 

Pseudotsuga . ...................... 25, 26, 37; pl. I 

menziesii . ............. 7, 10, 24, 25, 37, 38; pl. 5 

Pseudotsuga association . . . . . . . . . . . . . . . . . 10 

Pseudotsuga forest, Populus tremuloides- . 17 

pun gens, Picea . . . . . . . . . . . . . . . . . . . . . 7, 16 

Pussytoes . . . . . . . . . . . . . . . . . . . . . . . 8, 10 

Q,R 

Quaking aspen . . . . . . . . . . .......... . 9, 10, 12 

20 

8, 26 

7 

Quaternary palynology ........... . 

Quercus ...... . 

Quillwort ....... . 

Rabbitbrush . . . . . . . . . . . . . . . . . . . . 8 

Ragweed...... . . . . . . . . . . . . . . . . 8 

ramosissimum, Polygonum . . . . . . . . . . . . . . 9, 27, 28 

Ranunculaceae . . . . . . . . . . . . . . . . . 9, 29 

Ranunculus . . . . . . . . . . . . . . 9, 27 

aquatilis. . .... 9, 20, 32, 36; pl. 8 

Ratio, Gramineae/Pinus ...... . 20, 34, 36, 37 

Picea.j Pinus . . 20 

Ptnus albicaulis!Ptnus contorta . . 20, 31, 34, 36, 

Redcedar .. 

Reedgrass, northern 

References cited .. 

Rhamnaceae .... . 

Rhizopods ............ . 

rhodanthum, Sedum . 

37,38 

7 

9,15 

41 

9 

30 

. . . . . . . . . . . . . 8, 15, 28 
E48 

Page 

rhomboidea, Saxifraga ......... E9, 12, 29, 33; pl. 10 

River birch · 8 

Rock selaginella . . . . . . 7 

Rockcress . . . . . . . . . . 8, 10 

Rocky Mountain fringed gentian . . . . . 8, 15 

Rocky Mountain juniper 7, 10 

Rorippa. . . . . . . . . . . . . 28 

isln.ndica .. 8, 28, 36; pl. 10 

Rosaceae . . . . . 9, 27,29 

rosea integrijolium, Sedum . . 8 

Rosecrown. . . . . . . . . . . . . . . 8, 15 

rostrata, Carex . . . . . . . . . . . . . . . . 9 

rotundifolia, Campanuln. . 8, 10 

Rubiaceae . . . . . . . . . . . . . . . . 9 

Rue, meadow . . . . . . . . . . . . . . . . . . . 9 

Rumex..... . ................. 9, 27, 31; pl. 4 

fueginus. . .. 9, 29, 37; pl. 6 

maritimus fueginus . . . . . . . . . . . . . . . . . 9 

paucijolius . . . . . . . . . . . . . . . . . . . . . . . . . 9 

salicijoli:us ..................... 29, 31, 36; pl. 6 

triangulivalvis . . . . . . 9 

Rush family . . . . . . . . . . 10, 12 

s 

Sagebrush . . . . . 8, 10 

big........ ················ 8,10 

Sago pondweed. . . . . . . . . . . . 10 

Salicaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 29 

salicijolt"us, Rumex . ................. 29, 31, 36; pl. 6 

triangulivalvis, Rumex . . . . . . . . . . . . . . 9 

Salix. . . . ............... 9, 26, 29, 31; pl. 4 

arctica . 9, 12 

ligulifolia . . . . . . . . . . . . . . . . . . 9, 14, 15 

subcoerulea . . . . . . . . . . ........... 9, 14, 15, 29 

sp.. . . . . . . . .. . . . . .. .. .. .. .. . . . . . . 17,38 

Sali:JJ.Sedum rhodanthum community, 

Caln.magrostis.. 15, 17 

Saltbush. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 10 

Sand bur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Sarcobatus ...................... 16, 17, 26, 31; pl. 2 

vermiculn.tus....................... 8, 10, 17 

Saxifraga caespitosa ............. 9, 12, 29, 33; pl. 10 

rhomboidea ................. 9, 12, 29, 33; pl. 10 

rivuln.ris . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

Saxifragaceae ......................... . 

Saxifrage, diamondleaf ................. . 

matted ........................... . 

Scirpus ............................... . 

acutus ............................ . 

scopulorum, Juniperus virginiana ....... 7, 

Scorpion-weed ........................ . 

Scrophulariaceae ...................... . 

Sedge ................................ . 

Sedum ln.nceoln.tum .................... . 

rhodanthum ...................... . 

rosea ............................. . 

integrijolium . ................. . 

Sedum rhodanthum community, 

9,29 

9,12 

9,14 

29 

9,17 

10,17,26 

8,10 

9,27 

10, 12,14 

8 

8, 15,28 

28 

8 

Calamagrostis-Salix- 15, 17 

Selaginella, rock . . . . . . . . . . . . . . . . . . . . . . . . 7 

Seln.ginelln.densa .. ............ 7,12,19,24, 27; pl. I 

seln.ginoides . . . . . . . . . . . . . . . . . . . . . . . . 7, 24 

Selaginellaceae . . . . . . . . . . . . . . . . . . . . . . . . . 7, .24 

seln.ginoides, Seln.ginelln.................. 7, 24 

Shepherdiacanadensis . . . . . . . . . . . . 8, 12,17 

Shrubby cinquefoil. . . . . . . . . . . . . 9, 15 

Sibbaldia procumbens . . . . . . . . . . . . . . 9, 29, 33 

Silvery lupine . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 10 

INDEX 

Page 

Sitanion hystrix . . . . . . . . . . . . . . E10 

longifolium . . . . . . . . . . . . . . . . . 10 

Small bedstraw... . . . . . . . . . . . . . . . 9, 14 

Small bladderwort . . . . . . . . . . . . . . . . . . . . . . 8, 14 

Small clubmoss......................... 12 

Smartweed, water.. 9, 14 

Smooth brome . . . . . . . . . . . . . . . . . . . . . . 9 

Soft cinquefoil. . . . . . . . . . . . . . . . . . . . . . . . . 9 

Sorrel, alpine . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 36 

South Arm of Yellowstone Lake . . . . . . 5 

Sparganiaceae . . . . . . . . . . . . . . . . . . . . . . 10 

Sparganium ..................... . 10, 17, 27, 30,33 

angustijolium 10, 30 

minimum.. . . . . . . . . . . . . . . . 10,30 

Sphagnaceae . 7 

Sphagnum............................. 7, 30,38 

warnstorfianum . . . . . . . . . . . . . . . . . . . . 7, 38 

Sphagnum moss . . . . . . . . . . 7 

spicata, Luzuln. . . . . . . . . . . . . . . . . . . . 10, 15 

spicatum excalbescens, MyriophyUum . . . . . 8, 28 

Spike woodrush . . . . . . . . . . . . . . . . . . . . . . . . 10, 15 

Spikerush . . . . . . . . . . . . . . . . 9 

Spruce, Colorado blue............ 7 

Engelmann . . . . . . . . . . . . . . . . . . . . . . . 7, 12 

Squirrel-tail . . . 10 

Steppe, Artemistil . . ................. 10, 13, 16, 17 

Gramineae-Artemisia tridentata...... 17 

Artemisia 10, 16, 17 

Sticky-laurel . . . . . . . . . . . . . . 9 

Stipa......... . . . . . . . . . . . . 10 

Strawberry.. . . . . . . . . . . 9 

Stonecrop . . . . . 8 

Subalpine environment. . . 36 

Subalpine fir . 7, 12 

subalpinum, Eriogonum 10, 12 

subcoerulea, Salix ..................... 9, 14, 15, 29 

Subfamily Liguliflorae . 

Subfamily Tubuliflorae. 

Subzone, Betuln. .... 

. .. 8, 26, 28, 31 

. ...... 8, 26, 28, 31 

Picea-Abies-Pinus contorta ........ . 

25, 91, 39 

25,98 

Pinus contorta ..................... 25, 97, 40 

Pinus contorta-Pinus albicault"s . ..... . 

Populus . . . . . . . ............ . 

Swamp-laurel . . . . . ................ . 

T 

25,97 

25, 95, 39 

8 

Tansymustard . . . . . . . . . . . 8 

Temple Lake Stade . . . . . . . . . . 5, 25, 38 

tenui/olia, Alnus . .................... 7, 28, 37; pl. 6 

Thalictrum 9, 27 

thermalis, Gentiana..... 8, 15 

Gentianopsis . . . . . . . 8 

Thinleaf alder . . . . . . . . . . 7, 37 

torreyana, Ephedra . . . . . . . . . . . . . . . . . . . . . 7, 26 

Tower mustard . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Trail Creek pond . . . . . . . . . . . . . . . 6 

tremulnides, Populus.. . . . 9, 10, 12 

triangulivalvis, Rumex salicijolius 9 

trichocarpa, Populus ...................... 9, 29, 36 

tridentata, Artemisia .............. . 8, 10, 16, 17, 19 

trifidum, Galium. . . . . . . . . . . . . . . . . . . . . . . . 9, 14, 15 

trijlqiata, Menyanthes ...... 8, 14, 15, 25, 28, 38; pl. 6 

Tsuga................................. 27 

heterophylln. . . . . . . . . . . . . . . . . . . . . . . 7, 27 

mertensiana . . . . . . . . . . ..... 7, 27; pl. I 

Tubuliflorae, subfamily ................ 8, 26, 28,31 

Page 

Tufted hairgrass . . . . . . . . . . . . . . . . . . . . E9, 15 

Tundra communities . . . . . . . . . . . . . . . . . . . . 40 

Two Ocean Plateau ........ 4, 5, 12, 13, 29, 34, 39, 40 

Typha................................. 37; pl.IO 

angustijolia........................ 10,30 

ln.tifolia .................... 10,27,30,33;pl.2 

sp..... . . . . . . . . . . . . . . . . . . . . . . 38 

Typhaceae . . . . . . . . . . . . . . . . . . . . . . . . 10, 90 

u 

Umbelliferae . . . . . . . . . . . . . . . . . . 9, 27 

Umbrellaplant . . . . . . . . . . . . . . . . . . . . . . . . . 9, 10 

Urtica................................. 9, 27 

Urticaceae...... . . . . . . . . . . . . . . . . . . . . . . 9 

Utriculn.ria minor . . . . . . . . . . . . . . . . . . . . . . . 8, 14 

vulgaris . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 14 

utriculn.ta, Carex ..... 9,14, 15,17, 25, 30, 37, 38; pl. 7 

uva-ursi, Arctostaphylos . . . . ....... 8, 10, 12 

v 

Vaccinium . . . . . pl. 10 

myrtiUus . . . . . . . . . . . . . . . . . . . . . . 8, 12 

~-····· .......................... u.n 

vaginatus, Potamogeton................. 10, 30 

velutinus, Ceanothus.................... 9, 17,27 

vermiculn.tus, Sarcobatus............. 8, 10, 17 

verticiUatum, MyriophyUum . . . . . . . . . . . . . 8, 28 

vesicaria, Carex ............. 9, 17, 25, 30, 38; pl. 7 

virginiana scopulorum, Juniperus ....... 7, 10, 17, 26 

viridis, Ephedra. . ................... 7, 26; pl. I 

vivipara, Bistorta. . . . . . . . . . . . . . . . . . . 9, 12, 28 

Viviparous bistort . . . . . . . . . . . . . . 9, 12 

viviparum, Polygonum . . . . . . . . . . . . . . . . . . 9 

vulgaris, Utriculn.ria . . . . 8, 14 

w 

Walnut..... . . . . . . . . . .......... . 

Water crowfoot ....................... . 

Water smartweed . . . . ............... . 

Water starwort ....................... . 

W atermilfoil .......................... . 

Western alder ......................... . 

Western dwarf mistletoe ....... . 

Western hemlock . . .......... . 

Wheatgrass . . . . . ............ . 

Whitebark pine. 

Wild-rye 

Willow ..... . 

blue. 

Willow dock. 

Willow herb, pale ...... . 

Wind River Range, Wyo .......... . 

Woodrush .................... . 

spike ........ . 

Y,Z 

8 

9, 33 

9, 14 

8 

8, 37 

28 

8 

7 

9,10 

7, 12 

9, 10 

9 

9 

9,31 

8 

41 

10, 12 

10,15 

Yarrow.............. 8, 10 

Yellow pond lily . . . . . . . . . . . . . . . . . . . . . . . . 8, 14 

Yellowstone Lake basin, history . . . . . . . . . . 2 

Yellowstone Lake Ranger Station, climate . 2 

Zone, basal . . . . . . . 30 

defined............ 23 

Picea-Juniperus-Pinus albicaulis ...... 25, 90, 39 

Pinus contorta ..................... 25, 96, 39 

See also Subzone. 
PLATES 1-10 

Contact photographs of the plates in this report are available, at cost, from the U.S. Geological 

Survey Photographic Library, Box 25046 Federal Center, Denver, Colorado 80225. 
PLATE 1 

Fossil spores and pollen from Buckbean fen core. x 535. 

FIGURE 1. Bryophyte spore; 890-cm depth. 

la. Midfocus. 

lb. High focus. 

2. Ephedra viridis type pollen; 340-cm depth. 

2a. High focus. 

2b. Midfocus. 

3. Picea pollen; 850-cm depth. 

4. Pinus contorta type pollen; 160-cm depth. 

5. Pinus albicaulis type pollen; 920-cm depth. 

5a. High focus. 

5b. Slightly lower focus. 

6. Pseudotsuga pollen; 700-cm depth. 

7. SelagineUa densa spore; 920-cm depth. 

8. Juniperus pollen; 890-cm depth. 

9. Tsuga mertensiana; 240-cm depth. 

9a. Midfocus. 

9b High focus. 
GEOL ICAL SURVEY PROFESSIONAL PAPER 729-E PLATE I 

l a 1 b 

2b 

BRYOPHYTE, EPHEDRA, PICEA, PINUS, PSEUDOTSUGA , SELAGINELLA , JUNIPERUS, AND TSUGA 
PLATE 2 

Fossil pollen from Buckbean fen core. x 1,054. 

FIGURE 1. Nuphar; 340-cm depth. 

2. Typha latifolia tetrad; 943-cm depth. 

3. Sarcobatus; 700-cm depth. 

3a. High focus. 

3b. Slightly lower focus. 

4. Compositae, subfamily Liguliflorae; 920-cm depth. 

4a. High focus. 

4b. Midfocus. 

5. Ambrosia; 850-cm depth. 

6. MyriophyUum; 440-cm depth. 

6a, High focus, to 6c, midfocus. 

7. Arceuthobium; 700-cm depth. 

7a. High Focus. 

7b. Midfocus. 

8. cf. Mimulus; 160-cm depth. 

Ba. High focus. 

8b. Midfocus. 
GEOLOGICAL SURVEY 

3b 

5 

la 

PROFESSIONAL PAPER 729~E PLATE 2 

3a 

4a 4b 

6a 6b 6c 

lb 8a Bb 

NUPHAR, TYPHA, SARCOBATUS, COMPOSITAE, AMBROSIA, MYRIOPHYLLUM, 

ARCEUTHOBIUM, AND MIMULUS 
PLATE 3 

Fossil pollen from Buckbean fen core. x 1,054. 

FIGURE 1. Menyanthes; 60-cm depth. 

la, High focus, told, low focus. 

2. Polemonium; 842-cm depth. 

2a, High focus, to 2c, midfocus. 

3. Bistorta; 900-cm depth. 

3a, High focus, to 3c, midfocus. 

4. Koenigia islandica; 850-cm depth. 

4a, High focus, to 4d, midfocus. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 729-E PLATE 3 

la lb lc ld 

4a 4b 4c 4d 

MENYANTHES, POLEMONIUM, BISTORTA , AND KOENIG/A 
PLATE 4 

Fossil pollen and alga from Buckbean fen core. x 1,054. 

FIGURE 1. Oxyria type pollen; 850-cm depth. 

1a. High focus, tole, midfocus. 

2. Rumex pollen; 920-cm depth. 

2a. High focus, to 2c, midfocus. 

3. Potentilla palustris pollen; 0-cm depth. 

3a. Equatorial view. 

3b. Polar view. 

4. Populus pollen; 842-cm depth. 

4a. High focus. 

4b. Slightly lower focus. 

5. Salix pollen; 900-cm depth. 

5a, High focus, to 5c, midfocus. 

6. Pediastrum, a green alga; 920-cm depth. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 729-E PLATE 4 

la lb lc ld 

le 2a 2b 

3a 3b 4a 4b 

5a 5b 5c 

6 

OXYRIA, RUMEX, POTENTILLA, POPULUS, SALIX. AND PEDIASTRUM 
PLATE 5 

Fossil and modern conifer needles. x 11. 

FIGURE 1-3. Juniperus communis. 

1. Fossil needle tip; Buckbean fen core, 820- to 825-cm depth. 

2. Fossil needle (near base); Buckbean fen core; 825- to 830-cm depth. 

3. Modern needle; RGB- 199. 

4, 5. Picea engelmannii. 

4a, Fossil needle, and 4b, cross section; Lilypad pond core, 930- to 935-cm 

depth. 

5a, and 5b, Modern needle, and 5c, cross section; COLO 180762. 

6, 7. Pinus albicaulis. 

6a, Fossil needle, and 6b, cross section; Buckbean fen core, 360- to 365-cm 

depth. 

7a, Modern needle, and 7b, cross section; R. G. Baker collection. 

8, 9. Pinus contorta. 

Ba, Fossil needle, and 8b, cross section; Buckbean fen core, 360- to 365-cm 

depth. 

9a, Modern needle, and 9b, cross section; R. G. Baker collection. 

10, 11. Pseudotsuga menziesii. 

lOa, Fossil needle, and lOb, cross section; Buckbean fen core, 350- to 355-cm 

depth. 

lla, Modern needle, and llb, cross section; R. G. Baker collection. 
GEOLOGI AL SUR VEY PROFESSIONAL PAPER 729-E PLATE 5 

5b 

5o ·, 

2 

3 

4b 

5c 

8o 

6o 7o 9o 

lOa llo 

6b 7b 

8b 

9b lOb llb 

J UNIPERUS, P!CEA, PINUS, AND PSEUDOTSUGA 
PLATE 6 

Fossil and modern fruits, scales, seeds, perianth, and bracts. x 11. 

FIGURE 1, 2. Alnus tenuifolia fruits. 

1. Fossil fragment; Buckbean fen core, 400- to 405-cm depth. 

2. Modern; COLO 2181. 

3, 4. Betula glandulosa catkin scales. 

3. Fossil; Lilypad pond core, 885- to 890-cm depth. 

4. Modern; COLO 2250. 

5, 6. Menyanthes trifoliata seeds. 

5. Fossil; Buckbean fen core, 55- to 60-cm depth. 

6a, 6b. Modern; RGB-197. 

7, 8. Rumex fueginus perianth. 

7. Fossil; Buckbean fen core, 445- to 450-cm depth. 

8. Modern; COLO 56854. 

9- 11. Rumex salicifolius fruits. 

9. Fossil; Lilypad pond core, 880- to 885-cm depth. 

10, 11. Modern; COLO 181168. 

12, 13. Populus balsamifera bracts. 

12. Fossil fragments; Buckbean fen core, 805- to 810-cm depth. 

13. Modern; COLO 107394. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 729-E PLATE 6 

4 

6a 

5 

6b 

9 10 11 

ALNUS, BETULA, MENY .ANTHES, RUMEX, AND POPULUS 
PLATE 7 

Fossil and modern fruits, perigynia, and fruit-stones. x 11. 

FIGURE 1. Nuphar luteum ssp. polysepalum. Fossil fruit; Buckbean fen core, 360- to 365-cm 

depth. 

2-4. Carex limosa fruits. 

2. Fossil; Buckbean fen core, 0- to 5-cm depth. 

3, 4. Modern; RGB -152. 

5 - 7. Carex vesicaria perigynia. 

5. Fossil; Buckbean fen core, 0- to 5-cm depth. 

6, 7. Modern; RGB- 87. 

8-10. Carex ultriculata perigynia. 

8. Fossil; Buckbean fen core, 5- to 10-cm depth. 

9, 10. Modern; RGB- 277. 

11, 12. Potamogeton alpinus fruit with covering. 

11. Fossil; Buckbean fen core, 820- to 825-cm depth. 

12. Modern; COLO 131646. 

13, 14. Potamogeton filiformis fruit-stones. 

13. Fossil; Lilypad pond core, 980- to 985-cm depth. 

14. Modern; COLO 199776. 

15- 17. Potamogeton gamineus fruit-stones. 

15. Fossil; Buckbean fen core, 450- to 455-cm depth. 

16, 17. Modern; COLO 72388. 
GEOLOGICAL SU RV EY PROFESS! ON A L PAPER 729-E PLATE 7 

2 3 

5 

13 

15 16 17 

NUPHAR , CAREX, AND POTAMOGETON 
PLATE 8 

Fossil and modern seeds and fruits. x 17. 

FIGURE 1-3. Descurainia californica seeds. 

la, lb. Fossil; Lilypad pond core, 910- to 915-cm depth. 

2, 3. Modern; COLO 13079. 

4- 7. Epilobium glandulosum-type seeds. 

4. Fossil; Buckbean fen core, 145- to 150-cm depth. 

5-7. Modern-Epilobium adenocaulon (included within this morphological 

type); COLO 181161. 

8-10. Epilobium lactiflorum seeds. 

8. Fossil; Lilypad pond core, 805- to 810-cm depth. 

9, 10. Modern; COLO 134413. 

11, 12. Ranunculus aquatilis fruits. 

11. Fossil; Lilypad pond core, 870- to 875-cm depth. 

12. Modern; RGB -151. 

13-15. Potentilla biennis fruits. 

13. Fossil; Lilypad pond core, 885- to 890-cm depth. 

14, 15. Modern; COLO 209920. 

16-19. Potentilla gracilis type fruits. 

16, 17. Fossil; Lilypad pond core, 955- to 960-cm depth. 

18, 19. Modern; RGB-124a. 

20-22. Potentilla palustris fruits. 

20. Fossil; Buckbean fen core, 5- to 10-cm depth. 

21, 22. Modern; RGB-148. 
GEOLOG ICAL SURVEY 

lo 

1 b 

16 

PROFESSIONAL PAPER 729-E PLATE 8 

5 

2 

4 

3 

13 

21 

20 

19 

22 

DESCURAINIA, EPILOBIUM, RANUNCULUS, AND POTENTILLA 

9 

8 

10 

14 

15 
PLATE 9 

Fossil perigynia, fruits, and seeds from Buckbean fen core and modern 

perigynia, fruits, and seeds. x 16. 

FIGURE 1, 2. Carex aquatilis perigynia and fruits. 

1. Fossil; 165- to 170-cm depth. 

2. Modern; COLO 53127. 

3-5. Carex canescens perigynia and fruits. 

3. Fossil; 0- to 5-cm depth. 

4, 5. Modern; R. G. Baker collection. 

6- 8. Carex diandra perigynia and fruits. 

6. Fossil; 0- to 5-cm depth. 

7, 8. Modern; RGB-147. 

9-11. Eleocharis macrostachya fruits. 

9. Fossil, corroded; 475- to 480-cm depth. 

10, 11. Modern; COLO 95235. 

12-14. Glyceria maxima ssp. grandis seeds. 

12. Fossil; 435- to 440-cm depth. 

13, 14. Modern; COLO 20242. 

15, 16. Naias jlexilis seeds. 

15. Fossil; 475- to 480-cm depth. 

16. Modern; COLO 106552. 
PROFESSIONAL PAPER 729-E PLAT!-. 9 

GEOLOGICA L S RVEY 

4 

2 

6 

11 

13 

12 

15 16 

14 

CAREX, ELEOCHARIS, GLYCER!A, AND NA JAS 
PLATE 10 

Fossil and modern fruits and seeds. x ca. 27 

FIGURE 1. cf. Vaccinium. Fossil seed; Lilypad pond core, 990- to 995-cm depth. 

2-6. Sa;x;ifraga rhomboidea seeds. 

2a, 2b. Fossil; Lilypad pond core, 930- to 935-cm depth. 

3-6. Modern; COLO 38885. 

7-11. Sa;x;ifraga caespitosa seeds. 

7. Fossil; Lilypad pond core; 930- to 935-cm depth. 

8-11. Modern; COLO 180253. 

12- 14. Rorippa islandica-type seeds. 

12. Fossil; Buckbean fen core, 410- to 415-cm depth. 

13, 14. Modern; COLO 197251. 

15 - 17. Typha fruits. 

15. Fossil; Buckbean fen core, 665- to 670-cm depth. 

16. Modern fruit with covering membrane; COLO 41239. 

17. Modern fruit with membrane removed; COLO 41239. 
PROFESSIONAL PAPER 729-£ PLATE 10 

GEOLOGI AL SURVEY 

2a 3 5 

6 

2b 

8 10 13 

7 

12 

14 

9 11 

15 17 

cf. VACCINIUM, SAX/FRAGA , RORIPPA, AND TYPHA 

u U.S. GOVERNMENT PRINTING OFFICE' 1976- 677-340/92 
Baker-LATE QUATERNARY VEGETATION HISTORY OF THE YELLOWSTONE LAKE BASIN, WYO.-Geological Survey Professional Paper 729-E