Vascular plants of west-central Montana-identification guidebook

FLORA

In this area of west-central Montana, 1,607

taxonomic entities (taxa) have been collected.  These

include 1,501 species and 106 well-defined varieties,

representing 485 genera and 106 families.  Intro-

duced species total 250.  These are most numerous

in the populated valleys.  In contrast, in the timber-

line and alpine zones only one introduced species

was found—common dandelion (Taraxacum

officinale) (Lackschewitz 1970).  Although this list

is the result of considerable investigation, users

may well find additional species in the study area;

and in that case, the author would appreciate being

informed of such discoveries.

Of the 12 species strictly endemic to Montana, five

occur in our study area (Lesica and others 1984).

These are:

Arabis fecunda

Endemic in

Rollins

western Montana

Draba daviesii

Restricted to the

(C.L. Hitchc.) Rollins

Bitterroot Mountains

Lesquerella humilis

Restricted to the

Rollins

Bitterroot Mountains

Saxifraga tempestiva

Endemic in

Elvander & Denton

western Montana

Trisetum orthochaetum

Endemic in Missoula

soil horizon development occurs locally, generally

at lower elevations.  Continuous sods have devel-

oped only in small areas of the timberline and

alpine zones.  More often, Carex nigricans and other

species form a sod locally in moist subalpine basins.

In rocky, nonforested areas at high elevation, most

vegetation appears in cracks and crevices and in

fellfield-like situations.  Soils developed from the

Idaho batholith granites are strongly acidic.

The Lolo Creek, O’Brien Creek, Blue Mountain

area west of Missoula (fig. 1) is characterized by

mountains of modest height, with few summits

reaching 2,130 m (7,000 ft) in elevation.  The Lolo

Creek valley provides a major low-elevation route

up to the Bitterroot/Clearwater River divide at

1,585-m (5,200-ft) Lolo Pass.  Highway U.S. 12

follows the general route of explorers Lewis and

Clark up Lolo Creek to the pass.  Immediately west

of the pass lies the moist inland-maritime forest of

the Clearwater River drainage, in northern Idaho,

where Pacific coast conifers are abundant. These

include western redcedar (Thuja plicata), grand fir,

Pacific yew (Taxus brevifolia), western white pine

(Pinus monticola), and mountain hemlock (Tsuga

mertensiana).  Little of this maritime vegetation

extends eastward into the Lolo Creek drainage or

elsewhere into west-central Montana (Arno 1979).

From the Lolo Creek valley north to the Clark

Fork River, most of the country is underlain by

layers of the Precambrian Belt sedimentary rocks.

These rocks surface also on Mormon Peak and the

northeastern tip of the Bitterroot Range.  In the

vicinity of Lolo Hot Springs a distinctive granitic

intrusion is known as the Lolo batholith.

Although it has a relatively mild, Pacific-

influenced climate, this region’s forests are

generally drier than those of either northwestern

Montana or adjacent northern Idaho (Arno 1979).

Thus, west-central Montana has only small

amounts of Pacific Coast forest species such as

western redcedar, western white pine, Pacific yew,

Clintonia uniflora, Adenocaulon bicolor, and

Tiarella trifoliata, and these species are largely

restricted to moist canyon-bottom sites or seepage

areas.  Some of these small populations may be

remnants of extensive distributions that occurred

during a wetter climatic period.  Grand fir is locally

common, but is much less abundant than it is

farther west.  West-central Montana is, however,

characterized by an abundance of intermountain

forest species, which become rare farther east.

These include western larch (Larix occidentalis),

alpine larch (Larix lyallii), Pacific ponderosa pine

(var. ponderosa), Xerophyllum tenax, Menziesia

ferruginea, and Luzula hitchcockii.

Prior to 1900, fires were very frequent at lower

and middle elevations (Arno 1980), with the result

5

Hitchc.

County

In addition to the endemics mentioned, 22 species

occur in Montana only in our study area of Ravalli

County and southwestern Missoula County:

Agrostis borealis

Allium acuminatum

A. parvum

A. simillimum

Athysanus pusillus

Castilleja covilleana

Chrysosplenium tetrandrum

Erigeron evermannii

Eriogonum pyrolifolium v. coryphaeum

E. umbellatum v. stellatum

Eupatorium occidentale

Idahoa scapigera

Lewisia columbiana

Linanthastrum nuttallii

Lomatium bicolor

Mertensia bella

Penstemon payettensis

Saxifraga tolmiei

Sedum debile

Synthyris missourica

Trifolium eriocephalum

T. gymnocarpon

The main distributions of these species lie to the

west of Montana.  In fact, the vegetation of the

Bitterroot Mountains is similar to that of the

Cascade Mountains of Washington and Oregon

in several respects: an abundance of plants of the

heath family (Ericaceae), the dominance of Carex

nigricans in moist sites at high elevations, and the

appearance at and above timberline of two tall

herbaceous plants, Angelica roseana and Polygonum

phytolaccaefolium.

Seven species common and widespread in

Montana mountain ranges, including the Sapphire

Range, could not be found in the Bitterroot

Mountains.  These are: Agropyron latiglume, Poa

alpina, Anemone multifida, Oxytropis (all species),

Bupleurum americanum, Androsace septentrionalis,

and Viola canadensis.

EARLY BOTANICAL EXPLORATION

Meriwether Lewis and William Clark were the

first European explorers and botanical collectors

in west-central Montana.  They traversed the

Bitterroot River and Lolo Creek valleys twice; first

on their journey west in early September 1805, then

on the return trip in June and July 1806.  According

to Cutright (1969), Cypripedium montanum, the

white lady’s slipper orchid, was first collected and

described by Lewis at or near Lolo Hot Springs on

June 30, 1806.  Four species were collected July 1,

1806, at “Traveller’s Rest” at the mouth of Lolo

Creek.  These collections were later described and

named by German botanist Frederick Pursh:

Lewisia rediviva (bitterroot, the Montana State

flower), Sedum stenopetalum (stonecrop), Ortho-

carpus tenuifolius (owl-clover), and Trifolium

microcephalum (small-head clover).  (Thompson

[1985] provides a more detailed account of Lewis

and Clark and other botanical collectors in Montana

prior to 1865.)

Nathaniel Wyeth was the next plant collector to

travel through west-central Montana.  Born in 1802

in Cambridge, MA, Wyeth became a friend of

Thomas Nuttall, the famous Harvard University

botanist. When Wyeth prepared an overland

expedition to the Oregon country, Nuttall asked him

to bring back a few plants.  Traveling south from

the Flathead Valley, Wyeth entered the Bitterroot

Valley near the present city of Missoula in the

spring of 1833 and departed it from the south across

Gibbons Pass.  Although he collected a great

number of plants, most of them were lost or spoiled

by accidents.  Still, Wyeth delivered 113 species to

Nuttall, who described the genus Wyethia in his

honor.

In 1843, Karl Andreas Geyer collected here.

Geyer was born in 1809 in Dresden, Germany—a

gardener’s son who became a gardener himself.

He developed a keen interest in botany and corre-

sponded for years with Sir William Jackson Hooker,

a leading English botanist who profoundly influ-

enced him.  On his second expedition to the

American West, Geyer traveled through the

Beaverhead Valley and across Gibbons Pass to the

Bitterroot Valley.  He stayed at Father Pierre

DeSmet’s newly established St. Mary’s Mission at

today’s town of Stevensville.  Geyer was hospitably

received and used the Mission as a base camp for

exploring and collecting.  He remained until mid-

winter 1843-44, when he left for Spokane.  In his

reports, he praised the beauty of the Bitterroot

Valley and the surrounding mountains and forests.

He wrote eloquent accounts of the area’s gigantic

old ponderosa pines and of the majestic Thuja trees

(western redcedar) in the mountain canyons to the

west.  He also described the Indian (Salish) inhab-

itants and their methods of collecting camas

(Camassia quamash) bulbs and bitterroots.  About

a dozen species were named after Geyer, including

the following plants common in our area: Carex

geyeri, Allium geyeri, Physaria geyeri, and Salix

geyeriana.  He also named several frequently

occurring species, including Melica bulbosa, Viola

orbiculata, Ranunculus alismaefolius, and Micro-

seris nutans.

Sereno Watson first named and described about

three dozen of our common plant species, including

6

Aquilegia flavescens, Lomatium cous, Lonicera

utahensis, and Saxifraga occidentalis.  Watson also

established three new genera—Hesperochiron, Les-

querella, and Orogenia; however, this was only a

minor part of the scientific contributions of this self-

taught botanist.  Watson came first to the West with

the King expedition in 1867.  He then served as a

general handyman and horse wrangler.  In 1880 he

traveled from Dillon through the Bitterroot Valley

to Missoula and then westward over Lolo Pass.  On

this trip he was collecting for the Gray Herbarium,

now located at Harvard University.

From 1880 to 1923, Marcus E. Jones lived in Salt

Lake City and collected mainly in the Great Basin;

but his wide-ranging collecting expeditions led him

at least once into the Bitterroot Valley.  This is

documented by his 1910 collection of Trifolium

gymnocarpon, hollyleaf clover, from the valley of

the West Fork of the Bitterroot River.  Marcus

Jones became a leading botanist, discovering and

naming several plants native to western Montana.

During the 19th century, botanists and plant

collectors in our region were explorers, mostly

from the cultural centers of the eastern United

States.  In the late 1800’s, the founding of the

State university at Missoula (now the University of

Montana) and the agricultural college at Bozeman

(now Montana State University) ushered in the era

of resident botanists.  The history of floristic explor-

ation in the western United States has always been

closely connected to the personalities teaching

botany and the curators of the herbaria.  Morton

G. Elrod, who joined the University of Montana in

1897, was a biology professor and an active botan-

ical collector in western Montana.  By 1909 he had

obtained about 7,000 botanical specimens, which

he entrusted to his colleague J. E. Kirkwood.

Kirkwood became an immensely active botanist

and forest ecologist.  He formally established the

University of Montana herbarium and collected

extensively even in the rugged mountains, traveling

by horseback and afoot.  For instance, he was the

first botanist on Lolo Peak and Trapper Peak.

In 1932, C. Leo Hitchcock took over as curator of

the University of Montana herbarium.  A nationally

known botanist and leading author of today’s

standard Pacific Northwest floras (Hitchcock and

others 1955-69; Hitchcock and Cronquist 1973), he

devoted much of his time to exploration and collec-

ting throughout western Montana, from bottom

lands to mountain summits.  By 1937, when

Hitchcock left for a similar position at the

University of Washington in Seattle, he had helped

broaden and modernize the mission of the herbar-

ium, striving to build a complete representation of

the native flora to serve both science and the public.

REFERENCES

Alt, David D.; Hyndman, Donald W. 1986. Roadside

geology of Montana. Missoula, MT: Mountain

Press. 427 p.

Arno, S. F. 1979. Forest regions of Montana. Res.

Pap. INT-218. Ogden, UT: U.S. Department of

Agriculture, Forest Service, Intermountain Forest

and Range Experiment Station. 39 p.

Arno, S. F. 1980. Forest fire history in the Northern

Rockies. Journal of Forestry. 78: 460-465.

Arno, S. F.; Habeck, J. R. 1972. Ecology of alpine

larch (Larch lyallii Parl.) in the Pacific Northwest.

Ecological Monographs. 42: 417-450.

Arno, S. F.; Hammerly, R. P. 1984. Timberline—

mountain and arctic forest frontiers. Seattle, WA:

The Mountaineers. 304 p.

Cutright, P. R. 1969. Lewis and Clark: pioneering

naturalists. Chicago, IL:  University of Illinois

Press. 279 p.

Davis, R. J. 1952. Flora of Idaho. Provo, UT:

Brigham Young University Press. 835 p.

Dorn, R. D. 1984. Vascular plants of Montana.

Cheyenne, WY: Mountain West Publishing. 276 p.

Finklin, Arnold I. 1983. Weather and climate of the

Selway-Bitterroot Wilderness. Moscow, ID:

University Press of Idaho. 144 p.

Gleason, H. A.; Cronquist, A. 1963. Manual of vas-

cular plants of northeastern United States and

adjacent Canada. Princeton, NJ: Van Nostrand.

810 p.

Gruell, G. E.; Schmidt, W. C.; Arno, S. F.; Reich,

W. J. 1982. Seventy years of vegetative change

in a managed ponderosa pine forest in western

Montana—implications for resource management.

Gen. Tech. Rep. INT-130. Ogden, UT: U.S.

Depart-ment of Agriculture, Forest Service,

Intermountain Forest and Range Experiment

Station. 42 p.

Harrington, H. D. 1954. Manual of the plants of

Colorado. Authorized by the Colorado State Board

of Agriculture and prepared with the cooperation

of Colorado A&M College. Denver, CO: Sage

Books. 666 p.

Hermann, Frederick J. 1970. Manual of the Carices

of the Rocky Mountains and Colorado Basin.

Agric. Handb. 374. Washington, DC: U.S.

Department of Agriculture, Forest Service. 397 p.

Hitchcock, C. Leo; Cronquist, Arthur; Ownbey,

Marion; Thompson, J. W. 1955-69. Vascular

plants of the Pacific Northwest. Seattle, WA:

University of Washington Press. 5 vols.

Hitchcock, C. L.; Cronquist, A. 1973. Flora of the

Pacific Northwest, Seattle, WA: University of

7

Washington Press. 730 p.

Kuijt, Job. 1982. A flora of Waterton Lakes National

Park. Edmonton, AB: University of Alberta Press.

684 p.

Lackschewitz, Klaus H. 1970. Alpine and timberline

flora in the Bitterroot Mountains, Montana. In:

Proceedings of the Montana Academy of Sciences.

30: 1-30.

Lackschewitz, Klaus. 1986. Plants of west-central

Montana—identification and ecology: annotated

checklist. Gen. Tech. Rep. INT-217. Ogden, UT:

U.S. Department of Agriculture, Forest Service,

Intermountain Research Station. 128 p.

Lesica, Peter; Moore, G.; Peterson, K. M.; Rumely,

J. M. 1984. Vascular plants of limited distribution

in Montana. Monogr. No. 2, Montana Academy of

Sciences, Supplement to the Proceedings. Vol. 43.

61 p.

Moss, E. H. 1959. Flora of Alberta. Toronto, ON:

University of Toronto Press. 546 p.

Mueggler, W. F.; Stewart, W. L. 1980. Grassland

and shrubland habitat types of western Montana.

Gen. Tech. Rep. INT-66. Ogden, UT: U.S. Depart-

ment of Agriculture, Forest Service, Intermoun-

tain Forest and Range Experiment Station. 154 p.

Pfister, R. D.; Kovalchik, B.; Arno, S.; Presby, R.

1977. Forest habitat types of Montana. Gen. Tech.

Rep. INT-34. Ogden, UT: U.S. Department of

Agriculture, Forest Service, Intermountain Forest

and Range Experiment Station. 174 p.

Ross, C. P.; Andrews, B. A.; Witkind, I. J. 1955.

Geologic map of Montana. Washington, DC: U.S.

Department of the Interior, Geological Survey.

Thompson, L. S. 1985. Montana’s explorers: the

pioneer naturalists 1805-1864. Helena, MT:

Montana Magazine, Inc. 109 p.

Weber, W. A. 1976. Rocky Mountain flora. Boulder,

CO: Colorado Associated University Press. 479 p.

HOW TO USE THIS MANUAL

To identify an unknown plant, first use the Key

to Plant Families (page 12).  Once the correct family

has been determined, use the key to the genera

which follows the description of the morphological

characters of the family.  After identifying the

genus, use the key to species within the genus.

The keys are dichotomous, consisting of a series

of paired alternatives, each preceded by the same

number.  The two statements are designed to be

mutually exclusive.  Examine the specimen and its

habitat and decide which alternative is true.  Be

sure to read both alternatives before making a

decision.  At the end of the chosen alternative there

is a number or a name.  A number directs you to

another couplet (pair of alternatives) in the key.

Repeat the above procedure, choosing the appro-

priate statement in each couplet until a name is

arrived at.  Verify the family, genus, and species

indicated in the keys by reading the descriptions of

that family, genus, and species following the keys.

To avoid excessive repetition, words used in species

descriptions are usually explained in the descrip-

tions of the family or genus.  Technical terms are

also explained in the Glossary (page 8).

To aid identification, some of the larger genera

have been divided into subgeneric groups based on

similarity of appearance or habitat (for example,

species with yellow flowers, species of meadows).

Within genera and the subgeneric groups, species

followed by their descriptions are presented in order

of their decreasing commonness in west-central

Montana.  The distribution listed at the end of each

description is for the species, not any particular

variety or subspecies.  Taxonomic nomenclature

used here generally follows that of Hitchcock and

Cronquist (1973).

Dichotomous keys have often been adapted from

those in Hitchcock and others (1955-69), Dorn

(1984), and Kuijt (1982).  Species descriptions were

developed by the author based on field experience

and Davis (1952), Dorn (1984), Harrington (1954),

Hermann (1970), Hitchcock and others (1955-69),

Moss (1959), and Weber (1976), and were edited to

follow the style and order of Hitchcock and others

(1955-69).

Species are grouped by division, and divisions are

organized phylogenetically, with the more primitive

plants first.  Thus the nonflowering plants (club-

mosses, horsetails, ferns, and conifers) are placed

first, followed by the flowering plants, which are

further divided into dicots (broad-leaved plants) and

monocots (grasses, sedges, lilies, etc.).  Within these

groups, species are arranged alphabetically by

family, genus, and species.  Scientific names follow

the nomenclature of  “Flora of the Pacific

Northwest” by Hitchcock and Cronquist (1973).  A

small number of species in the checklist are not

found in Hitchcock and Cronquist, and references

must be sought in the recent literature or in a flora

of the eastern United States, such as Gleason and

Cronquist (1963).  Scientific names that have

widespread use but are considered incorrect by

Hitchcock and Cronquist (synonyms) are placed in

brackets and follow the accepted name.  Each

scientific name (taxon) is followed by a common

name, most of which are also taken from “Flora of

the Pacific Northwest.”

Two additional species were found so recently that

they could not be incorporated in this manual.  They

are Atriplex heterosperma and Suaeda depressa,

both members of Chenopodiaceae.  Both are rare in

our area and were found on the east side of the

Bitterroot Valley.  They are indicators of alkaline

soil.

8

GLOSSARY

A-.  A prefix denoting a lack or without.

Achene.  A dry, 1-seeded fruit that does not open along

regular lines.

Acuminate.  With concave sides long tapering to

a point.

Acute.  With mostly straight sides tapering to a sharp

point.

Adventitious.  Arising not from the usual place.

Alpine.  Occurring above treeline in mountains.

Alternate.  Arranged with one structure (leaf, stem, etc.)

per node.

Amphibious.  With the potential to inhabit water or

land, but not removed from surface water.

Annual.  A plant, usually with slender taproot,

completing its life cycle in a single growing season.

Anther.  The pollen-bearing portion of the stamen,

remote from the point of attachment.

Anthesis.  That period when a flower is open for

pollination.

Apex.  The furthest or highest point, the tip.

Apical. At the top or tip.

Appressed.  Pressed close to another organ or surface.

Aquatic.  Growing (anchored or floating) in water.