Status review and taxonomic studies of Astragalus molybdenus, U.S.D.A. Forest Service, Region 1, Lewis and Clark National Forest

MONTANA
STATE

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Nl Isrta

STATE DOCUMENTS COLLECTIOn
OOT C1992

MONTANA STATE LIBRARY

1515 E. 6th AVE.
HELENA, MONTANA 59620

STATUS REVIEW AND TAXONOMIC STUDIES
OF Astragalus molybdenus

U.S.D.A. FOREST SERVICE - REGION 1
LEWIS AND CLARK NATIONAL FOREST

MONTANA

Prepared by:

Lisa Ann Schassberger and J. Stephen Shelly

Montana Natural Heritage Program

State Library Building

1515 E. 6th Avenue

Helena, MT 59620

Challenge Cost-share Project
Order No. 40-03K0-9-0194

This is an abridged report

For the full report please contact:

The Montana Natural Heritage Program

1515 E Sixth Ave

Helena, Montana 59620

406-444-3009

ACKNOWLEDGMENTS

These studies were funded under a challenge cost-share agreement
between the Montana Natural Heritage Program and the U.S. Forest
Service, Lewis & Clark National Forest. We thank Wayne Phillips
and Dr. Angela Evenden for their support and interest. We
gratefully acknowledge the technical support from Dr. Matt Lavin
and Sarah Mathews, Montana State University (chloroplast DNA
analysis), and Dr. Greg Brown, University of Wyoming (isozyme
electrophoresis) ; their work provided valuable information on
taxonomic relationships among the study populations. Hollis
Marriott, Wyoming Natural Diversity Data Base, provided
invaluable information on populations in Wyoming and Colorado,
and collected plant specimens from those states. Rupert Barneby,
New York Botanical Garden, examined collections from all three
states, and shared his valuable perceptions regarding the tv/o
species. Dr. Angela Evenden and John Pierce (U.S. Forest
Service, Missoula, Montana) assisted with the field surveys and
sample collections in Montana; their help and companionship was
invaluable to the success of this work.

TABLE OF CONTENTS

Page

I . INTRODUCTION 1

I I . METHODS 2

A. SURVEY 2

B. TAXONOMIC STUDIES 2

III. SPECIES INFORMATION 2

A. PRESENT LEGAL OR OTHER FORMAL STATUS 2

B. DESCRIPTION 3

C. GEOGRAPHICAL DISTRIBUTION 5

D. HABITAT 8

E. POPULATION DEMOGRAPHY AND BIOLOGY 11

F. TAXONOMIC STUDIES 12

G. POPULATION ECOLOGY 19

H. LAND OWNERSHIP 19

IV. ASSESSMENT AND MANAGEMENT RECOMMENDATIONS 19

A. THREATS TO CURRENTLY KNOWN POPULATIONS 19

B. MANAGEMENT PRACTICES AND RESPONSE 2 0

C. RECOMMENDATIONS FOR MAINTAINING VIABLE POPULATIONS 20

D. STATUS RECOMMENDATION AND FURTHER ASSESSMENT NEEDS 20

E . SUMMARY 21

V. LITERATURE CITED 2 3

VI. ELEMENT OCCURRENCE PRINT-OUTS AND MAPS 2 5

VI I . PHOTOGRAPHS 3 8

ii

I. INTRODUCTION

SCIENTIFIC NAME: Astragalus molybdenus Barneby.

COMMON NAME: Leadville milk-vetch.

FAMILY: Fabaceae (= Leguminosae ; Pea Family).

The first known collection of Astragalus molybdenus was made
in 1873, in the Park Range of Colorado (Barneby 1964).
Barneby (1949) initially named the species A. plumbeus .
However, since this name had already been applied to a
different species in Russia, he subsequently renamed it A.
molybdenus (Barneby 1950) . Within the genus, A. molybdenus
was placed in the Phacoid group, in section Minerales . The
Phacoid group is thought to be the most primitive one within
the genus. The chromosome number for A. molybdenus remains
unknown. Once this information is obtained, it may suggest
that its affinities lie elsewhere in the genus (Barneby
1964) .

For many years, A. molybdenus was known only from alpine
areas near Leadville and Aspen, Colorado. In 1982, an
Astragalus specimen was collected, in flower, on Mount
Wright, Teton County, Montana (Lackschewitz et aX 1984).
Although the specimen lacked ripe pods, Rupert Barneby (New
York Botanical Garden) identified it as Astragalus
molybdenus; he felt it was different from collections of A.
shultziorum. a very closely related species recently
described (Barneby 1981) from western Wyoming (Klaus
Lackschewitz, pers. comm.). This station on Mount Wright
represented a disjunction of approximately 960 km (600 mi)
northward from the A. molybdenus populations in Colorado.
Thus, the range was divided, with A. shultziorum occurring
between the Montana and Colorado locations of A. molybdenus .

Owing to the overall morphological similarities between A.
molybdenus and A. shultziorum, the specific status of the
latter has been questioned. Dorn (1988) treated A.
shultziorum as a synonym of A. molybdenus. Thus, in 1989,
the Montana Natural Heritage Program and the V'Jyoming Natural
Diversity Database initiated status survey projects that
included an assessment of the taxonomic relationship of
these species. The Lewis and Clark National Forest and the
Montana Natural Heritage Program established a challenge
cost-share agreement. The goals of this project were: 1.)
to study the distribution of A. molybdenus populations on
the Forest, 2.) to collect specimens that would allow more
detailed comparison of the Montana and Colorado populations
with those of A. shultziorum from Wyoming, and 3.) to
collect leaf samples for use in molecular systematic
studies. It was hoped that the taxonomic status of the

populations in all three states could then be more clearly
defined.

II. METHODS

This project consisted of two parts: 1) field surveys to
determine the distribution, abundance, and habitat of
Astragalus molybdenus in Montana, and to assess threats to
the populations; and 2) a taxonomic study to determine the
relationship between A. shultziorum populations in Wyoming,
and A. molybdenus populations in Colorado and Montana.

A. SURVEY

In Montana, the known site on Mt. Wright was relocated
and fully mapped. Additional searches were conducted
in potential habitat on peaks and ridges to the south
of Mt. Wright. These surveys were completed on 7-10
and 21-23 August 1989. The distribution information
obtained from these surveys is found in Section III.
C, pp. 5 and in the maps and occurrence records in
Section VI, pp. 25-37. Information obtained on
management needs and the biology of this species are
reported under the respective sections in the body of
this report.

B. TAXONOMIC STUDIES

A variety of approaches were used to assess the
taxonomic relationships among the Montana and Colorado
populations of A. molybdenus , and the Wyoming
populations of A. shultziorum. Plant leaf material was
collected from five Montana populations by the authors,
and from three sites in Colorado, and six sites in
Wyoming, by Hollis Marriott (Wyoming Natural Diversity
Data Base (WNDDB) . Leaf material was provided to Dr.
Matt Lavin, Montana State University, for chloroplast
DNA (cpDNA) analysis, and to Dr. Greg Brown, University
of Wyoming, for isozyme electrophoretic studies.
Additionally, full collections were sent to Rupert
Barneby of the New York Botanical Garden, an expert on
the genus Astragalus. Results of the taxonomic studies
are given in Section III. P., pp. 12-19.

III. SPECIES INFORMATION

A. PRESENT LEGAL OR OTHER FORMAL STATUS
1. FEDERAL STATUS

a. U.S. FISH AND WILDLIFE SERVICE: None.

b. U.S. FOREST SERVICE: Astragalus molybdenus
is currently included on the U.S. Forest
Service list of sensitive species for Region
1 (U.S. Department of Agriculture 1988).
Objectives and policy of the U.S. Forest
Service provide for the management and
protection of sensitive species under
sections 2670,22 and 2670.32 in the 1984
Forest Service Manual. Under these
guidelines, the Forest Service is to (a)
"maintain viable populations of all native
species of plants" (2670.22), and (b) "avoid
or minimize impacts to species whose
viability has been identified as a concern"
(2670.32.3) .

2. STATE: Astragalus molybdenus has been listed as
"rare" by the Montana Rare Plant Project (Lesica
et al . 1984). This category includes "those
species which are limited to a restricted
geographic range... in Montana." Globally,
Astragalus molybdenus is currently listed by the
Montana Natural Heritage Program (Shelly 1990) as
"very rare" (21-100 occurrences; global rank =
G3) . It is listed as "critically imperiled in
Montana because of extreme rarity" (state rank =
SI) . These ranks do not currently provide any
direct legal protection for A. molybdenus.

DESCRIPTION

1. GENERAL NONTECHNICAL DESCRIPTION: A member of the
Pea Family (Fabaceae) , Astragalus molybdenus is a
low-growing, loosely mattjfed plant, with prostrate
to upright stems. Leaves are borne alternately
along the stems, and each compound leaf consists
of 9-25 oval leaflets. Plants may bear 1-6 small
(0.5 inch) purple, or occasionally whitish, pea-
type flowers. Fused green sepals (outer floral
leaves) surround each flower, and are covered with
long, black hairs. The fruit is a small,
pendulous, curved pod (adapted from Reel et al .
1989) . See Section VII, pp. 38-46, for color
photos of plants and habitat.

2. TECHNICAL DESCRIPTION: Low, loosely tufted or
matted perennial, with a slender taproot and
loosely, sometimes extensively branching
subterranean stems persisting as rhizome-like
caudex-branches (sometimes adventitiously rooting
and thus vegetatively reproductive) , the stems
with fine, nearly straight, appressed and

ascending hairs up to 0.4-0.5 mm. long, greenish-
cinereous to silvery-gray, the leaflets sometimes
medially glabrescent above, the inflorescence
black-hairy; stems of the season largely
subterranean, the aerial tips prostrate or weakly
ascending, 0.5-6 (14) cm, long, the internodes all
short, or a few of them developed and up to 1.5
(4) cm. long, mostly shorter; stipules 2-5 mm.
long, submembranous , purplish, glabrous dorsally,
the lowest becoming pallid and scarious, all
amplexicaul and connate through + half their
length, the free blades deltoid or lanceolate,
obtuse or subacute; leaves 1.5-7 cm. long,
petioled, with (9) 17-25 ovate, ovate-oblong, or
elliptic, obtuse, mostly crowded, folded or
involute leaflets 2-10 mm. long; peduncles at
anthesis incurved-ascending, procumbent in fruit,
1-3 (6.5) cm. long; racemes loosely 3-6 flowered,
the flowers loosely ascending, the axis scarcely
elongating, 3-10 (15) mm. long in fruit; bracts
membranous, lanceolate, ovate-acuminate, 2.5-5 mm.
long; pedicels at anthesis 0.5-1.5 mm. long, in
fruit either straight or arched outward, 1-2 mm.
long; bracteoles 0-2, minute when present; calyx
5.2-7 mm. long, densely black-strigulose , the
oblique disc 0.5-0.8 mm. deep, the campanulate
tube 3-4.2 mm. long, 2.7-3.2 mm. in diameter, the
broadly subulate teeth 2-3 mm. long; petals pink-
purple, dull lilac, or whitish with banner veined
and distally suffused with lilac, the keel-tip
always maculate; banner recurved through + 45
degrees, ovate-cuneate, notched, 10.7-12.5 mm.
long, 5.2-7.2 mm. wide; wings 9.3-10.9 mm. long,
the claws 3.3-4.4 mm., th4 oblong-obovate , obtuse,
slightly incurved blades 6.6-8 mm. long, 2.5-2.7
mm, wide; keel 8.8-9.7 mm. long, the claws 3.8-4.7
mm., the broadly lunate blades 5.3-5.7 mm. long,
2.3-2.8 mm. wide, incurved through 90-100 degrees
to the bluntly triangular apex; anthers 0.45-0.6
mm. long; pod ascending (humistrate) , sessile or
nearly so, obliquely ovoid or ovoid-ellipsoid, a
trifle incurved, 7-11 mm. long, +3.5 mm. in
diameter, rounded at base, abruptly deltoid-beaked
and cuspidate at apex, subtriquetrously compressed
with acute ventral and rounded lateral angles,
flattened or somewhat depressed dorsally but
hardly sulcate, the prominent ventral suture
either straight or a trifle concave in profile,
the thin submembranous, densely black- or more
rarely partly white-strigulose valves not
inflexed; dehiscence not seen; seeds (not seen

quite ripe) + 4.2-4.5 mm. long (adapted from
Barneby 1964) .

3. LOCAL FIELD CHARACTERS: Astragalus molybdenus is
only positively identified in fruit. It is
distinguished from other co-occurring Astragalus
species by its small, distinctly three-angled
(making it appear slightly inflated) , curved
fruits, and leaflets, which have hairs only along
their margins and dorsal surfaces.

Vegetatively , Astragalus molybdenus is similar to,
and co-occurs (in Montana) with, A. bourgovii , A.
alpinus , and A. vexillif lexus . Fruits of A.
vexillif lexus are curved, and resemble those of A.
molybdenus , but are not three-angled (appearing
flat in side view) . The fruits of A. bourgovii
and A. alpinus are only gently curved, and not
distinctly three-angled.

Other useful (but not definitive) characteristics
in the vegetative state include the yellow-green
stems of A. molybdenus (A. vexillif lexus has
distinctly reddish stems) , and the presence of
minute hairs only along the margins and dorsal
side of the leaflets (A. bourgovii and A. alpinus
both have minute hairs that extend onto the
adaxial side of the leaflets) .

GEOGRAPHICAL DISTRIBUTION

1. RANGE: In Montana, A. molybdenus is currently
known from eight populations in the Sawtooth
Range, Teton County, near' the headwaters of the
North and South Forks of the Teton River. The
locations are included in Figure 1, p. 6. These
populations occur within 10 air miles of one
another (U.S.G.S. 7.5' topographic maps: Our Lake
and Mt. Wright) . The Montana populations are
disjunct from populations in Colorado by nearly
960 km (600 mi). Limestone substrates are common
in the Sawtooth Range, and extensive areas of
potential habitat exist for some miles to the
north and south of these populations. There was
not enough time to thoroughly survey all the
potential habitat for this species.

The distribution of population centers of
Astragalus molybdenus in Montana and Colorado, and
A. shultziorum in Wyoming, is shown in Figure 2, p
7.

MONTANA

Figure 1. Locations of the eight Astragalus molybdenus populations
in the Sawtooth Range, Teton County, Montana. Numbers
next to dots indicate the presence of multiple
populations in close proximity.

Montana

A, molybdenus

Wyomin
A. shuLtziorum

Colorado
A. molybdenus

Fieure 2.

- indicate locations of population centers of
Astragalus molydenus in Montana and Colorado

- indicate locations of population centers of
Astragalus shultziorum in Wyoming.

8

2. CURRENT SITES: In 1989, field surveys of a
portion of the Sawtooth Range in Montana revealed
seven new populations of A. molybdenus. This
brings the total number of currently documented
populations in Montana to eight, all occurring in
Teton County. All of the populations occur on
lands managed by the U.S. Forest Service, Lewis
and Clark National Forest. Four of the populations
occur on the border of the Bob Marshall Wilderness
(Our Lake (002), Rocky Mountain-West (004), Rocky
Mountain-Northeast (005) , and Route Creek Pass
(006)) .

The legal descriptions, elevations, USGS
topographic map names, and locations of sites in
Montana are provided in Section VI, pp. 25-33.
Also, the exact locations are indicated on the
maps provided in Section VI, pp. 34-37.

3. HISTORICAL SITES: None known.

4. UNVERIFIED/UNDOCUMENTED REPORTS: None known.
D. HABITAT

1. ASSOCIATED VEGETATION: In Montana, A. molybdenus
occurs primarily as a member of alpine forb
communities. Populations also occur in the
subalpine, but only on very exposed sites, where
the microclimate is probably more similar to
alpine habitats. Plants were most often observed
growing in dense mats of Dryas octopetala . but
were also seen spreading in open scree. Plant
species that co-occur with A. molybdenus at one or
more of the sites include:

Androsace chamaeiasme sweet-flowered androsace

Anemone cylindrica candle anemone

Antennaria aromatica aromatic pussy-toes

Aquileqia jonesii limestone columbine

Arctostaphylos uva-ursi. . . kinnikinnick

Astragalus alpinus alpine milk-vetch

Astragalus bourgovii Bourgeau ' s milk-vetch

• Astragalus vexillif lexus . . bent-flowered milk-vetch

Bupleurum americanum American thorough-wax

Campanula rotundif olia . . . . lady's thimble

Cerastium arvense field chickweed

Claytonia megarhiza alpine springbeauty

Douglasia montana Rocky Mountain douglasia

Dryas octopetala white dryas

Erigeron compositus cut-leaved daisy

Erigeron lackschewitzii . . . Front Mountain erigeron

Hedvsarum sulphurescens . . . sulphur hedysarum

Juniperus communis common juniper

Kobresia bellardii Bellard's alpinesedge

Oxvtropis podocarpa stalked-pod crazyweed

Oxytropis viscida sticky locoweed

Poa qravana Gray ' s bluegrass

Polemonium pulcherrimum. . . skunk-leaved polemonium

Potentilla fruticosa shrubby cinquefoil

Potentilla diversifolia . . . diverse-leaved cinquefoil

Salix nivalis snow willow

Saxifraqa bronchialis spotted saxifrage

Sibbaldia procumbens creeping sibbaldia

Smelowskia calycina alpine smelowskia

Ziqadenus eleqans glaucous zigadenus

Of these, Oxytropis podocarpa and Erigeron
lackschewitzii are included on the U.S. Forest
Service, Region 1, sensitive plant and watch
lists, respectively.

2. TOPOGRAPHY: In Montana, populations of A.
molvbdenus occur at or above the krummholz zone in
areas where snow deposition occurs. These sites
range from nearly level, to steep slopes (0-35%).
Most sites in Montana have a north or northwest
aspect; however, populations do occur on south- or
east-facing slopes. The sites range from 7,263 to
8,120 feet in elevation.

In Colorado, recently surveyed A. molybdenus
populations occur from 11,900 to 12,500 feet in
elevation; it has been collected as high as 13,000
feet. As in Montana, these locations are above
treeline, in alpine forb fcommunities (Tamara
Naumann, pers. comm.).

In Wyoming, A. shultziorum occurs at elevations
from 8,800 to 10,500 feet, with most habitat
occurring between 9,000 and 10,000 feet.
Astragalus shultziorum appears to be restricted to
subalpine sites, only occasionally reaching into
the lowermost alpine zone (Marriott 1990) .

3. SOIL RELATIONSHIPS: The Montana populations of A.
molybdenus appear to be restricted to largely
stabilized, limestone scree slopes. This scree is
derived from limestone parent material of
Mississippian or Devonian origin (Mudge et al .
1983) . However, populations occasionally occur
where scree is unstable, as at Our Lake (002).
Populations were more often found in alpine forb
communities, especially in Dryas octopetala mats.

10

These mats appeared to be the principal soil
stabilizer in these habitats.

In Wyoming, A, shultziorum is almost always found
in calcareous habitats. Populations occur in
soils derived from the Triassic Thaynes limestone
and the Paleozoic Wells and Amsden Formations in
the Salt River Range. In the upper Spring Creek
drainage, A. shultziorum is occasionally found on
a fine red soil that may not be calcareous. In
the Teton Range, it occurs on several Paleozoic
limestones and dolomites, including the Darby,
Bighorn, Gallatin and Gros Ventre Formations.
Astragalus shultziorum is commonly found on
somewhat vegetated rocky soils. In the Salt River
Range, it is often a co-dominant on vegetated
talus or scree at the bases of slopes below
calcareous cliffs. In the Teton Range,
populations are especially well-developed on fine
soils with calcareous pebbles, apparently derived
from the Death Canyon member of the Cambrian Gros
Ventre Formation. At these locations it almost
always grows in open habitat, usually in subalpine
forb communities (Marriott 1990) .

REGIONAL CLIMATE: The Sawtooth Range is commonly
referred to as the "Front Range" of north-central
Montana. It is generally dominated by dry,
continental weather conditions. Much of the
yearly precipitation falls as rain or wet snov/ in
May and June, with large convective storms
providing the mid- and late summer moisture.
Winters are cold, dry, and windy, with
precipitation occurring m6stly in the form of
snow. For the Sawtooth Range populations,' the
nearest long term climatological station is at
Gibson Dam (4,735 ft), located approximately 14
air miles south and approximately 3,300 feet lower
than the plant populations. The mean annual
temperature for the time period 1951-1980 was
41.7° F. The mean maximum temperature for July
was 77.9° F, while the mean minimum temperature
for January was 11.2° F. For every 1,000 feet in
elevation gain, there is an estimated 5° drop in
temperature. Thus, the averages given above are
likely to be 10-15° higher than the actual
temperatures that the plant populations
experience. Mean annual precipitation was 18.52
inches (U.S. Department of Commerce 1982).

11

Populations of A. shultziorum and A. molybdenus
from Wyoming and Colorado, respectively, also
incur a similar continental climate.

POPULATION DEMOGRAPHY AND BIOLOGY

1. PHENOLOGY: In Montana, A. molybdenus flowers and
fruits from late July through August, depending on
climatic conditions and slope aspect. In 1989
large numbers of stems in nearly all of the
Montana populations were vegetative. Flowering
and fruiting was restricted to very small portions
of the populations during that year; the exception
was Our Lake (002). In 1990, flowering and
fruiting at Our Lake (002) was again high,
although it appeared that plants which had
flowered the year before were not in flower this
year.

Also in 1989, fifty percent of the individuals in
surveyed populations of A. molybdenus in Colorado
were in flower. During that same year,
populations of A. shultziorum in Wyoming only had
good fruit production in occasional local areas
within sites (Marriott 1990) .

From these observations, it appears that flowering
may be dependent on an interaction of the species'
internal rhythms, and local temperature and
moisture regimes.

2. POPULATION SIZE AND CONDITION: Populations of A.
molybdenus are generally quite large (often
greater then 10,000 stemsf. However, due to this
species' ability to establish new ramets through
rhizome extension, it is difficult to determine
the number of genetic individuals in a population.
Low flowering and fruiting frequencies probably
limit population increases by way of seedling
establishment.

3. REPRODUCTIVE BIOLOGY

a. TYPE OF REPRODUCTION: This species is a

perennial. In 1989, Montana populations were
observed to consist of approximately 90 to 95
percent vegetative ramets. As stated above,
flowering and fruiting was restricted to
small portions of the populations.

The establishment of new colonies through
rhizome extension appears to be common to all

12

the populations studied (Montana, V^Jyoming,
and Colorado) . At all of the A. shultziorum
sites, flowering and fruiting plants occur
only in small localized areas within
populations. It is possible that
"populations" of plants at given sites are
really collections of clones representing a
single or a few genotypes that have colonized
the area through vegetative propagation
(Marriott 1990) .

b. POLLINATION BIOLOGY: Unknown.

c. SEED DISPERSAL AND BIOLOGY: Fruits contain
approximately 7-9 ovules. Mature fruits
appear to drop from the plant before the
sutures open. Although most fruits probably
remain in the vicinity of the parent plant,
the submembranous pods could be easily
transported by the high winds that
characterize alpine habitats.

F. TAXONOMIC STUDIES

Three methods were used to examine the taxonomic
relationships between A. molybdenus (Montana and
Colorado) and A. shultziorum (Wyoming) :
morphological comparisons, analysis of chloroplast
DNA (cpDNA) fragmentation data (conducted by Dr.
Matt Lavin, Montana State University) , and
electrophoretic analysis of enzyme variation
(conducted by Dr. Greg Brown, University of
Wyoming) . The results of each of these studies
are summarized below, followed by a brief
discussion of their implications.

a. MORPHOLOGICAL COMPARISONS: Specimens from
populations in all three states were
submitted to various herbaria, including
Montana State University (MONT) , New York
Botanical Garden (NY) , and the Rocky Mountain
Herbarium, University of Wyoming (RM) . Dr.
Matt Lavin, Montana State University,
summarized the morphological characteristics
of plants from a limited number of herbarium
sheets from each state; these are presented
in Table 1, p. 13. The populations from
Montana and Wyoming show similarities with
respect to number of leaflets per leaf,
number of flowers per raceme, the nature of
the pod beak, and number of ovules per fruit.
With respect to seed size and flower

13

TABLE 1. Morphological characteristics of A. molybdenus
(Montana, Colorado) and A. shultziorum (Wyoming).* Summary
provided by Dr. Matt Lavin, Montana State University. Similar
values or characteristics among states are highlighted in bold
print in shaded boxes.

Colorado

Montana

Wyoming

Number of
leaflets/leaf

17-25

11-13

9-15

Number of
flowers/ raceme

3-6

1-4

1-3

Nature of pod
beak

short, stout

long, thin

long, thin

Number of
ovules/ovary

6

7-9

8-9

Size of seeds
(mm)

4-4.5

3.5-4.0

2.5-2.6

Flov/er color

purplish

purplish

whitish

* For this analysis, three herbarium sheets containing about five
plants each were studied from the Montana and Colorado A.
molybdenus populations. Five herbarium sheets with about five
plants each were studied from the Wyoming A. shultziorum
populations .

14

coloration, the Colorado and Montana
populations are similar.

Additional morphological comparisons were
summarized by Marriott (1990). The overall
appearance of the Wyoming plants (A.
shultziorum) is more open and loose than the
Montana and Colorado plants (currently
recognized as A_^ molybdenus) , which are more
compact and low-growing in habit. In the
Wyoming plants, the flowers are consistently
cream-colored, with pale purple striations on
the banner, and a purple spot on the tip of
the keel. The Colorado plants have petals
that are creamy at the base and blue-purple
at the tips. In Montana, the flowers are
more extensively blue-purple. Fruit
morphology among the states includes the most
distinctive differences among the three
regional units. Fruits from Colorado are the
smallest, are shorter in relation to width,
and have short beaks that contract abruptly
from the main body of the legume. In
Montana, the fruits are larger, longer
relative to width, arcuate in shape, and
taper gradually into a longer beak. Fruits
from Wyoming appear to be intermediate in
morphology. They are intermediate in size,
but approach Montana material in relation of
length to v/idth. Beaks are similar to
Montana material, but the legumes are little
if at all arcuate.

Rupert Barneby, New ^ork Botanical Garden,
also examined specimens from all three
states. In a letter to J.S. Shelly (10
January 1990), he stated that "(t)o my eye
the material all looks increasingly alike,
and I would now think that only one specific
taxon is recognizable, possibly divided into
varieties . "

cpDNA ANALYSIS: Chloroplast DNA is a
circular strand of DNA contained in the
chloroplasts (photosynthetic organelles) of
plant cells. These circular molecules can be
isolated from the cells, and differences in
their genetic sequences can be studied by
fragmenting them with restriction enzymes;
these enzymes break the strands when they
"find" certain DNA base pair sequences. The
resulting fragments are then examined

15

electrophoretically (separated on
electrically charged gels) , and a "map" of
the sequence of the fragments and their size
is developed. These maps are then analyzed
by computer, and diagrams of phylogenetic
(evolutionary) relationships and the degree
of cpDNA variation can be generated. The
results of such studies for this Astragalus
complex are presented in Figures 3 and 4, pp.
16-17. Three populations in each state were
studied. The results indicate that the
majority of the cpDNA genetic variation is
partitioned between populations in different
states, and that there is relatively little
variation among populations within a single
state (Fig. 3). The amount of variation
among the states is very high (Lavin et aJL.
1990) , approaching levels observed between
full species. It was not clear from the
analyses of the data whether the cpDNA among
the three states is monophyletic (evolved
from a common ancestor) . The analysis in
Figure 4 included one additional computer
"step" (i.e., it was not the most
parsimonious analysis) , but it does suggest
that the populations in the three states do
share a common cpDNA ancestor. Most
significantly, the results did reveal that at
least the Montana (A^ molybdenus^ and Wyoming
(A^ shultziorum) populations are derived from
a common ancestor.

ELECTROPHORETIC ANALYSIS OF ENZYME VARIATION:
This technique also Involves a study of the
genetic variation within and among
populations, but the subjects of study are
enzymes. Enzymes are proteins whose amino
acid sequences are determined by the nuclear
DNA (chromosomes); hence, differences between
the enzymes, as detected by separating them
on electrically charged gels, directly
reflect genetic differences. In this study,
five populations from Montana, four from
Wyoming, and three from Colorado were
examined. The results were generally
inconclusive, but they do suggest that the
populations are not highly divergent from one
another in terms of chromosomal genetic
variation. The sample size (number of
individuals per population) was small,
however, and an expanded study would be
needed to obtain statistically significant

16

Figure 3. Chloroplast DNA genetic distances among populations of Astragalus
molybdenus (Montana and Colorado) and A. shultziorum (Wyoming) .

Teton Co. populations

Sheep Pass
Lincoln Co.

Switt Creek

A. shultziorum

Taylor Pass
Gunn ison Co

North London Mines

a Hoosier Ridge

Park Co.

MONTANA
Teton Co.

Rocky Mt.
.0003]

Mt. Wright
& Teton Pk.

Astragalus molybdenus

cpDNA restriction site analysis
Nei's (1979) genetic distance
Fitch-Margoliash Dendrogram

COLORADO

17

Figure 4. Computer analysis (cladograra) comparing chloroplast DNA restriction
site differences within and among species of Astragalus , including populations
of A. molybdenus ("COLORADO" and "MONTANA") and A. shultziorum ("WYOMING").

B B B A vexilliflexus

IS 2S se 102
24 43 1C3 I Q^^M''^- glMflOrUS

^-Bmw

34 fl2 108113

BBBB'^ spatulat,

us

A bourgovii

3« 98 105107
16 21 28 31 39 4« 48 84 88 81 83 84 | ^ J || [[ COLORADO (Park CO.)

among state population comparisons
reveal at least 23 restriction
site differences (mininum
genetic distance = .0065)

rCmEMWWMMWWMM

78

-COLORADO (Gunnison Co.)

2 3 7 18 24 4S 47 88 89 83 87 89 80 94 97 99

-«m«m^

\— MONTANA (Mt. Wright, Teton Pk.)

04

^MONTANA (Rocky Mt.)

43 83 88 87 88 82 S«

L-tMWHHH

9 10 12 13 22 20 28 27 37 44 71 88 89 93 98 110

|— WYOM/AVG (Teton Co.)

30 11 2 {—WYOMING (Sheep Pass)

^WYOMING (Swift Creek)

1 4 8 U 19 20 38 38 42 81 74 78 87

miMllMMHHA canadensis

monophyletic cpDNA of
A. molybdenus

126 steps

CI = 114/126 =0.904

23 32 33 3^ 81 83 80 72 88 90 91 101108109111114

^ ^^^-VHtUWMWMMMMMMMWWA.aboriginum

' ^^" 14 34 40 41 49 80 88 98 77 93 93 94 99 100

■ ■■■MllBBBDm^l-A alpinus

measures of genetic variation (Brown 1990) .
Three of the seven enzymes studied did reveal
patterns indicating that the Colorado and
Montana populations are more similar to one
another than either is to the Wyoming
populations. The results also suggest the
possibility of polyploidy (duplication of the
full sets of chromosomes, resulting in higher
chromosome numbers) , again especially in the
Colorado and Montana populations. Chromosome
counts would be very useful in further
clarifying the evolutionary relationships
within the A. molybdenus-shultziorum complex.

d. DISCUSSION: The results of each of these
studies indicate that there has been some
evolutionary divergence among the populations
of Astragalus in all three states. This
divergence is undoubtedly related to the
large geographic distances separating them.
The genetic studies do not align the
populations in a similar pattern; while the
cpDNA studies indicate a close relationship
between the Montana and Wyoming populations,
the enzyme studies suggest that the Colorado
and Montana populations are most similar
genetically. The cursory morphological
studies do not reveal any major differences
among the three states; however, the Montana
and Wyoming populations do share certain
features of fruit morphology. Thus, from a
taxonomic viewpoint, it may be appropriate to
recognize the populations from all three
states as members of' one widespread species;
these could perhaps be distinguished as
varieties, as suggested by Barneby. These
populations are slowly diverging owing to the
large present-day geographic gaps, and
subsequent lack of interbreeding, between
them. It is important to emphasize that the
populations in all three states are largely
clonal, and may represent only one or a few
genotypes in each state (Lavin et al. 1990,
Marriott 1990) . The extensive vegetative
reproduction, and relatively low observed
rates of sexual reproduction, probably
account for the low levels of genetic
variation between populations within each
state. These reproductive characteristics
would also promote genetic differentiation
between populations among the states (Lavin
et al. 1990) .

19

Final resolution of the taxonomy of this
complex is in progress, and will be published
in the scientific literature. The results
will be provided to the U.S. Forest Service
upon completion.

POPULATION ECOLOGY

1. BIOLOGICAL INTERACTIONS

COMPETITION: Astragalus molybdenus
apparently tolerates competition, as it was
often found in association with large Dryas
octopetala mats. In Montana, total ocular
vegetation cover (including A. molybdenus
plants) was often 100 percent. However, as
member of alpine communities, or open
subalpine communities, this species may not
be shade tolerant.

HERBIVORY: No evidence of herbivory was
observed in the field.

H. LAND OWNERSHIP

1. All of the known locations for A. molybdenus in

Montana are on the Lewis and Clark National Forest
in the Sawtooth Range. The exact locations are
provided in Section VI, pp. 25-37.

IV. ASSESSMENT AND MANAGEMENT RECOMMENDATIONS

A. THREATS TO CURRENTLY KNOWN POPULATIONS:

1. GRAZING: No threats. It is likely that these
habitats are grazed intermittently by wild goats
or sheep, but this probably does not threaten the
plant populations.

2. MINING: All of the locations for A. molybdenus
are at high elevations in the Sawtooth Range, on
the Lewis and Clark National Forest. Surveys for
this species should be initiated if oil drilling
or mining projects are proposed in high elevation
habitats with potential for supporting this
species .

3. TIMBER HARVESTING: No threats.

4. WEED CONTROL ACTIVITIES: Currently no threats.

20

MANAGEMENT PRACTICES AND RESPONSE: There are currently
no management practices that threaten the habitat of A.
molybdenus , nor any known means of enhancing
populations .

RECOMMENDATIONS FOR MAINTAINING VIABLE POPULATIONS: In
Montana, populations appear to be self-sustaining, and
most are in areas that receive little human impact.
Several areas, including Our Lake (002), are popular
destinations for hikers and campers. It may be
appropriate at some point to provide protection for the
populations, through special site designations and
public education.

1, CONSERVATION BIOLOGY: As discussed in the section
regarding the taxonomic studies, there has been
some morphological and genetic divergence among
the populations in Montana, Wyoming, and Colorado.
Thus, even if A. molybdenus and A. shultziorum are
ultimately combined into one varietally segregated
species, it will be very important to ensure the
long-term maintenance of populations in all three
states. In this way, the entire range of genetic
variation in the complex will be retained. This
will allow for a greater chance of successful
adaptation in the face of possible climatic
changes or other ecological shifts. In addition,
maintenance of as many populations as possible in
each state will retain the intrastate genetic
variation that is starting to appear as evidenced
by the cpDNA data. Lastly, the current
distribution of the A. molybdenus-shultziorum
complex is biogeographically unique, and
maintenance of population^ throughout its range
will allow for future scientific interpretation of
its fragmented occurrence pattern.

STATUS RECOMMENDATION AND FURTHER ASSESSMENT NEEDS: It
is recommended that this species be maintained on the
U.S. Forest Service, Region 1, sensitive plant species
list. Although most of the populations do occur in
remote areas that receive limited human impact, the
known sites are all within a 10 mile area. It is also
recommended that further surveys be conducted, to the
north and south of the known populations in Montana.
This would help to define the full range of this
species in the Sawtooth Range. Establishment of a
demographic monitoring study would reveal important
life history characteristics, such as fecundity and
life-span of individuals or clones.

21

SUMMARY

In 1989, the Lewis and Clark National Forest and the
Montana Natural Heritage Program entered a Challenge
Cost-share agreement. Under the agreement, the Montana
Natural Heritage Program conducted field surveys to
determine the distribution of Astragalus molybdenus
populations on Forest lands. In addition, plant
material was collected for morphologic and molecular
systematic studies to compare these populations to
Colorado populations, and to populations of Astragalus
shultziorum from western Wyoming.

Survey efforts revealed seven new populations of A.
molybdenus in the Sawtooth Range, Teton County,
Montana. All of these populations occur within 10
miles of the original collection site on Mt. Wright.
This brings the total number of known populations in
Montana to eight. All of the populations were quite
large, although it appears that populations expand by
cloning through rhizome extension, rather than by ^
establishment of new plants from seed. At least in
1989, sexual reproduction was limited to small portions
of most populations (the exception was at Our Lake
(002)). In 1990, flowering and fruiting again appeared
to be fairly extensive at Our Lake (002) .

Additional surveys could reveal more populations to the
north or south of the known populations, in areas where
calcareous soils occur in alpine or very open subalpine
(7,000 to 8,000 ft. in elevation) habitats.

The results of the taxonomic studies indicate that
there has been some evolutionary divergence among the
populations of Astragalus in all three states. The
genetic studies do not align the populations in a
similar pattern; while the cpDNA studies indicate a
close relationship between the Montana and Wyoming
populations, the enzyme studies suggest that the
Colorado and Montana populations are most similar
genetically. The cursory morphological studies do not
reveal any major differences among the three states;
however, the Montana and Wyoming populations do share
certain features of fruit morphology not found in
Colorado plants. Thus, from a taxonomic viewpoint, it
may be appropriate to recognize the populations from
all three states as members of one widespread species;
these could perhaps be distinguished as varieties, as
suggested by Barneby. It is important to emphasize
that the populations in all three states are largely
clonal, and may represent only one or a few genotypes
in each state (Lavin et al. 1990, Marriott 1990).

22

Final resolution of the taxonomy of this complex is in
progress, and will be published in the scientific
literature. The results will be provided to the U.S.
Forest Service upon completion.

23

V. LITERATURE CITED

Barneby, R.C. 1949. Pugillus Astragalorum XI: two new species.
Leafl. Western Bot. 5:193-197.

Barneby, R.C. 1950. A correction. Leafl. Western Bot. 6:70.

Barneby, R.C. 1964. Atlas of North American Astragalus.
Memoirs of the New York Botanical Garden 13:114-115.

Barneby, R.C. 1981. Dragma Hippomanicum VII: A new alpine

Astragalus (Leguminosae) from western Wyoming. Brittonia
33(2) :156-158.

Brown, G.K. 1990. Preliminary analysis of allozyme variation,
Astragalus molvbdenus and A. shultziorum. Unpublished
report to Wyoming Natural Diversity Data Base, Laramie.
University of Wyoming, Laramie. 10 pp., appendices.

Dorn, R.D. 1988. Vascular Plants of Wyoming. Mountain West
Publishing, Cheyenne, Wyoming. 340 pp.

Lackschewitz, K.H., P. Lesica, J.Pierce, J.K. Cory, and D.

Ramsden. 1984. Noteworthy collections - Montana. Madrono
31:254 .

Lavin, M., S. Mathews, C. Hughes, H. Marriott, and S. Shelly.
1990. Intraspecif ic chloroplast DNA diversity is high in
some wild species of Leguminosae. Amer. J. Bot. 77(6)
(supplement) : 144 (abstr. ) .

Lesica, P., G. Moore, K.M. Peterson, and'J.H. Rumely. 1984.
Vascular Plants of Limited Distribution in Montana.
Monograph No. 2, Montana Academy of Sciences, Supplement to
the Proceedings, Vol. 43. 61 pp.

Marriott, H. 1990. Survey and taxonomic study of Astragalus

shultziorum (Shultz's milkvetch) . Unpublished report to the
U.S Forest Service, Bridger-Teton and Targhee National
Forests, Wyoming. 14 pp., appendices.

Mudge, M.R., R.L. Earhart, J.W. Whipple, and J.E. Harrison.

1983. Geologic and Structure Maps of the Chouteau 1° x 2°
Quadrangle, Northwestern Montana. Montana Bureau of Mines
and Geology, Montana Atlas 3-A.

24

Reel, S., L.A. Schassberger , and W. Ruediger. 1989. Caring for
Our Natural Community: Region 1 - Threatened, Endangered
and Sensitive Species Program. USDA Forest Service,
Northern Region, Wildlife and Fisheries, Missoula, Montana.
309 pp., appendices.

Shelly, J.S. 1990. Plant species of special concern. Montana
Natural Heritage Program, Helena. 20 pp. (mimeo.).

U.S. Department of Agriculture, Forest Service. 1988. Sensitive

Plant Field Guide, Montana. U.S. Forest Service, Northern

Region: Range, Air, Watershed, and Ecology Unit. Missoula,
Montana.

U.S. Department of Commerce. 1982. Monthly Normals of

Temperature, Precipitation, and Heating and Cooling Degree
Days 1951-80. National Oceanic and Atmospheric
Administration, Climatography of the United States No. 81.
23 pp.

25

VI. ELEMENT OCCURRENCE PRINT-OUTS AND MAPS

26

ELEMENT OCCURRENCE RECORD
Astragalus molybdenus (Leadville milk-vetch)

Occurrence number: 001

Global rank;
State rank:

G3
SI

Survey site name:

EO rank:

EO rank comments:

Forest Service status: SENSITIVE LIST
USFWS Status: NONE

MOUNT WRIGHT

A

RELATIVELY LARGE POPULATIONS,

UNDISTURBED ALPINE AREAS.

County: TETON

USGS quadrangle: MOUNT WRIGHT

Township-range: 026N OlOW Section: 25, S2 ; Section: 36, NW4

Survey date: 1989-08-08
First observation: 1982
Last observation: 1989-08-29

Elevation: 8100

Slope/aspect: 0-35% / N, E, NE, LEVEL

Size (acres) : 25

Location :

SAWTOOTH RANGE, EAST AND NORTHEAST SLOPES OF MOUNT WRIGHT,
NORTH FORK TETON RIVER DRAINAGE.

Element occurrence data:

SIX SUBPOPULATIONS ; EXTENSIVE VEGETATIVE SPREADING, BUT VERY FEW
PLANTS FLOWERING AND FRUITING; POPULATION SIZE DIFFICULT TO ESTIMATE.

General site description:

ALPINE AND SUBALPINE AREAS, LIMESTONE SUBSTRATES; WITH DRYAS
OCTOPETALA, OXYTROPIS PODOCARPA, BUPLEURUM AMERICANUM, SMELOWSKIA
CALYCINA, SIBBALDIA PROCUMBENS .

Land owner/manager:

BOB MARSHALL WILDERNESS AREA

LEWIS & CLARK NATIONAL FOREST, ROCKY MOUNTAIN RANGER DISTRICT

Comments :

VOUCHERS - SHELLY, J.S. (1592), L. SCHASSBERGER, A. EVENDEN, AND J.
PIERCE, RM, 1989; SHELLY, J.S. (1593) AND A. EVENDEN, MONT, 1989.

Information source:

SHELLY, J.S. 1989. FIELD SURVEYS IN TETON COUNTY, 7-10, 21-23, AND
28-30 AUGUST.

Montana Natural Heritage Program

27
ELEMENT OCCURRENCE RECORD
Astragalus molvbdenus (Leadville milk-vetch)

Occurrence number: 002

Global rank: G3 Forest Service status: SENSITIVE LIST
State rank: SI USFWS Status: NONE

Survey site name: OUR LAKE

EO rank: A
EO rank comments:

County: TETON

uses quadrangle: OUR LAKE

Township-range: 024N 009W Section: 18, NE4SW4

Survey date: 1989-08-09 Elevation: 8120

First observation: 1989 Slope/aspect: 0-35% / NORTH, WEST,
LEVEL

Last observation: 1990-07-28 Size (acres) : 25

Location:

CA. 33 MILES WEST OF CHOTEAU . FROM THE WEST END OF F.S. ROAD n09,
TRAVEL 2 MILES SSW TO OUR LAKE; SITE IS IN BASIN ABOVE AND SOUTH OF
THE LAKE.

Element occurrence data:

HEAVILY IN FRUIT (1989). ONE LARGE POPULATION AND ONE SMALL
POPULATION; NUMEROUS SCATTERED INDIVIDUALS. MANY PLANTS IN FLOWER
(1990) .

General site description: '

IN TURFY, MOIST LIMESTONE SOIL, WITH DRYAS OCTOPETALA, CERASTIUM
ARVENSE, SMELOWSKIA CALYCINA, ERIGERON COMPOSITUS, AND POLEMONIUM
PULCHERRIMUM.

Land owner/manager:

LEWIS & CLARK NATIONAL FOREST, ROCKY MOUNTAIN RANGER DISTRICT

Comments :

VOUCHER - SCHASSBERGER, L.A. (343) AND J. PIERCE, NY, 1989.

Information source:

SCHASSBERGER, L.A. 1989. FIELD SURVEYS OF THE FRONT RANGE MOUNTAINS,
7-10 AND 21-23 AUGUST.

Montana Natural Heritage Program

28

ELEMENT OCCURRENCE RECORD
Astragalus molybdenus (Leadville milk-vetch)

Occurrence number: 003

Global rank: G3
State rank: SI

Forest Service status: SENSITIVE LIST
USFWS Status: NONE

Survey site name: TETON SKI AREA PEAK

EO rank: A
EO rank comments: REMOTE LOCATION.

County: TETON

USGS quadrangle: MOUNT WRIGHT

Township-range: 025N OlOW Section: 12, SE4 ; Section: 13, NW4

Survey date:

First observation:

Last observation:

1989-08-08 Elevation: 7960

1989 Slope/aspect: 0-35% / NW, SOUTH, EAST

1989-08-08 Size (acres) : 15

Location:

CA. 34 MILES WEST OF CHOTEAU, ON WEST SIDE OF PEAK ABOVE TETON PASS
SKI AREA, AND SOUTHWEST ALONG THE RIDGE OF MOUNT LOCKHART.

Element occurrence data:

TWO LARGE SUBPOPULATIONS .

General site description:

IN MOIST, TURFY LIMESTONE SOIL, WITH DRYAS OCTOPETALA, SMELOWSKIA
CALYCINA, OXYTROPIS VISCIDA, ANDROSACE CHAMAEJASME, SAXIFRAGA
BRONCHIALIS, HEDYSARUM SULPHURESCENS , ASTRAGALUS ALPINUS, AND ERIGERON
LACKSCHEWITZII. *

Land owner/manager:

LEWIS & CLARK NATIONAL FOREST, ROCKY MOUNTAIN RANGER DISTRICT

Comments :

VOUCHERS - SCHASSBERGER, L.A. (337) AND J. PIERCE, NY, 1989; (338),
MONT.

Information source:

SCHASSBERGER, L.A. 1989. FIELD SURVEYS OF THE FRONT RANGE MOUNTAINS,
7-10 AND 21-23 AUGUST.

Montana Natural Heritage Program

29

ELEMENT OCCURRENCE RECORD
Astragalus molybdenus (Leadville milk-vetch)

Occurrence niimber: 004

Global rank: G3 Forest Service status: SENSITIVE LIST
State rank: SI USFWS Status: NONE

Survey site name: ROCKY MOUNTAIN-WEST

EO rank: A
EO rank comments: LARGE COLONIES, IN UNDISTURBED ALPINE
AREAS .

County: TETON

USGS quadrangle: OUR LAKE

Township-range: 024N 009W Section: 19, S2; Section: 30, N2

Survey date: 1989-08-10 Elevation: 8000
First observation: 1989 Slope/aspect: 0-35% / N,NW,W

Last observation: 1989-08-10 Size (acres) : 20

Location :

SAWTOOTH RANGE, WEST AND NW SLOPES OF ROCKY MOUNTAIN PEAK, 0.3-0.75 AIR
MI. SOUTH TO SSE OF HEADQUARTERS CREEK PASS.

Element occurrence data:

FIVE SUBPOPULATIONS OBSERVED, SOME SPREADING EXTENSIVELY BY VEGETATIVE
REPRODUCTION; POPULATION SIZE DIFFICULT TO ESTIMATE.

General site description:

ALPINE HABITATS, 7640 - 9200', ALMOST ALWAYS IN DRYAS OCTOPETALA MATS
BUT OCCASIONALLY IN SCREE, ON LIMESTONE SOBSTRATE; WITH SMELOWSKIA
CALYCINA, ANTENNARIA AROMATICA, ANDROSACE LEHMANNIANA, SAXIFRAGA
BRONCHIALIS, ERIGERON LACKSCHEWITZII, SALIX NIVALIS, ZIGADENUS
ELEGANS.

Land owner/manager:

BOB MARSHALL WILDERNESS AREA

LEWIS & CLARK NATIONAL FOREST, ROCKY MOUNTAIN RANGER DISTRICT

Comments :

VOUCHERS-SHELLY, J.S. (1602) AND L.A. SCHASSBERGER, NY, MONT, 1989.

Information source:

SHELLY, J.S. 1989. FIELD SURVEYS IN TETON COUNTY, 7-10, 21-23, AND
28-30 AUGUST.

Montana Natural Heritage Program

30

ELEMENT OCCURRENCE RECORD
Astragalus molybdenus (Leadville milk-vetch)

Occurrence number: 005

Global rank: G3 Forest Service status: SENSITIVE LIST
State rank: SI USFWS Status: NONE

Survey site name: ROCKY MOUNTAIN-NORTHEAST

EO rank: A
EO rank comments: LARGE COLONIES, IN UNDISTURBED ALPINE
AND SUBALPINE AREAS.

County: TETON

USGS quadrangle: OUR LAKE

Township-range: 024N 009W Section: 20, SW4

Survey date: 1989-08-10 Elevation: 8040
First observation: 1989 Slope/aspect: 0-35% / N, NW

Last observation: 1989-08-30 Size (acres) : 20

Location :

SAWTOOTH RANGE, NORTH AND NE SLOPES OF ROCKY MOUNTAIN PEAK, 0.4-0.85 AIR
MILES EAST TO SE OF HEADQUARTERS CREEK PASS.

Element occurrence data:

THREE SUBPOPULATIONS OBSERVED, SOME SPREADING BY VEGETATIVE
REPRODUCTION; POPULATION SIZE DIFFICULT TO ESTIMATE.

General site description:

ALPINE AND SUBALPINE AREAS, 7440-8670', OFTEN IN DRYAS OCTOPETALA MATS
BUT OCCASIONALLY IN SCREE, ON LIMESTONE StBSTRATE.

Land owner/manager:

BOB MARSHALL WILDERNESS AREA

LEWIS & CLARK NATIONAL FOREST, ROCKY MOUNTAIN RANGER DISTRICT

Comments :

SIGHT RECORD, VOUCHER COLLECTED FROM WEST SIDE OF ROCKY MOUNTAIN
(004), SHELLY (1602) AND SCHASSBERGER; SEEDS FOR SYSTEMATIC STUDY
COLLECTED FROM NORTHERN SUBPOPULATION ; BORDERS WATERSHED 10030104.

Information source:

SHELLY, J.S. 1989. FIELD SURVEYS IN TETON COUNTY, 7-10, 21-23, AND
28-30 AUGUST.

Montana Natural Heritage Program

31

ELEMENT OCCURRENCE RECORD
Astragalus molybdenus (Leadville milk-vetch)

Occurrence number: 006

Global rank: G3 Forest Service status: SENSITIVE LIST
State rank: SI USFWS Status: NONE

Survey site name: ROUTE CREEK PASS

EO rank: B
EO rank comments: LARGE COLONIES, BUT SITE IS TRAVERSED BY
A HIKING TRAIL.

County: TETON

USGS quadrangle: OUR LAKE

Township-range: 025N OlOW Section: 36, SE4

Survey date: 1989-08-22 Elevation: 7263

First observation: 1989 Slope/aspect: 0-15% / E, NE, NW,
LEVEL

Last observation: 1989-08-23 Size (acres) : 2

Location:

SAWTOOTH RANGE, ROUTE CREEK PASS, ON DIVIDE BETWEEN MIDDLE

FORK NORTH FORK TETON RIVER AND ROUTE CREEK, LEWIS & CLARK N.F. TRAIL

#108.

Element occurrence data:

ONE POPULATION; EXTENSIVE VEGETATIVE SPREADING, BUT LITTLE FLOWERING
AND FRUITING; SITE IS TRAVERSED BY A MODERATELY-USED PACK TRAIL;
POPULATION SIZE DIFFICULT TO ESTIMATE.

/

General site description:

SUBALPINE AREA, ON GRAVELLY LIMESTONE SUBSTRATE; WITH DRYAS
OCTOPETALA, POTENTILLA FRUTICOSA, JUNIPERUS COMMUNIS, ZIGADENUS
ELEGANS, ANTENNARIA AROMATICA, ANDROSACE LEHMANNIANA, SMELOWSKIA
CALYCINA, HEDYSARUM SULPHURESCENS , CAMPANULA ROTUNDIFOLIA , DOUGLASIA
MONTANA, AQUILEGIA JONESII.

Land owner/manager:

BOB MARSHALL WILDERNESS AREA

LEWIS & CLARK NATIONAL FOREST, ROCKY MOUNTAIN RANGER DISTRICT

Comments :

VOUCHERS-SCHASSBERGER, L.A. (353) AND J.S. SHELLY, NY, MONT, 1989;
BORDERS WATERSHED 10030104.

Information source:

SHELLY, J.S. 1989. FIELD SURVEYS IN TETON COUNTY, 7-10, 21-23, AND
28-30 AUGUST.

Montana Natural Heritage Program

32

ELEMENT OCCURRENCE RECORD
Astragalus molybdenus (Leadville milk-vetch)

Occurrence nvimber: 007

Global rank: G3
State rank: SI

Survey site name;

EO rank;

EO rank comments;

Forest Service status: SENSITIVE LIST
USFWS Status: NONE

TETON PEAK

A

LARGE COLONIES, IN UNDISTURBED REMOTE

HABITAT.

County: TETON

USGS quadrangle: MOUNT WRIGHT

Township-range: 025N OlOW Section: 36, NE4

Survey date:

First observation:

Last observation:

1989-08-22 Elevation: 7600

1989 Slope/aspect: 3-35% / N, E, NE

1989-08-22 Size (acres) : 5

Location:

SAWTOOTH RANGE, 0.35-0.85 AIR MI. SE OF TETON PEAK, 0.75

AIR MI. NORTH TO NE OF ROUTE CREEK PASS, MIDDLE FORK NORTH FORK TETON

RIVER DRAINAGE.

Element occurrence data:

THREE COLONIES; EXTENSIVE VEGETATIVE SPREADING, BUT LITTLE FLOWERING
AND FRUITING; POPULATION SIZE DIFFICULT TO ESTIMATE.

General site description:

ALPINE AND SUBALPINE TURF, LIMESTONE GRAVtL AND SCREE; OFTEN IN DRYAS
OCTOPETALA MATS, WITH BUPLEURUM AMERICANUM, ASTRAGALUS BOURGOVII,
HEDYSARUM SULPHURESCENS , POTENTILLA FRUTICOSA, ANDROSACE LEHMANNIANA,
POLEMONIUM PULCHERRIMUM, PEDICULARIS CONTORTA, ZIGADENUS ELEGANS,
GENTIANA CALYCOSA, ACHILLEA MILLEFOLIUM, PENSTEMON PROCERUS,

Land owner/manager:

LEWIS & CLARK NATIONAL FOREST, ROCKY MOUNTAIN RANGER DISTRICT

Comments :

SIGHT RECORD, VOUCHER COLLECTED AT NEARBY ROUTE CREEK PASS SITE
(SCHASSBERGER (353) AND SHELLY) .

Information source:

SHELLY, J.S. 1989. FIELD SURVEYS IN TETON COUNTY, 7-10, 21-23, AND
28-30 AUGUST.

Montana Natural Heritage Program

33

ELEMENT OCCURRENCE RECORD
Astragalus molvbdenus (Leadville milk-vetch)

Occurrence nvimber: 008

Global rank: G3 Forest Service status: SENSITIVE LIST
State rank: SI USFWS Status: NONE

Survey site name: OLD BALDY

EO rank: A
EO rank comments: LARGE COLONIES IN UNDISTURBED ALPINE
AREA.

County: TETON

USGS quadrangle: OUR LAKE

Township-range: 024N OlOW Section: 01, E2

Survey date: 1989-08-23 Elevation: 7420
First observation: 1989 Slope/aspect: 8-35+% / N, NW

Last observation: 1989-08-23 Size (acres) : 10

Location :

SAWTOOTH RANGE, NORTH SLOPES OF OLD BALDY, CENTERED 0.65

AIR MI. NORTH OF SUMMIT SADDLE, MIDDLE FORK NORTH FORK TETON RIVER.

Element occurrence data:

THREE COLONIES; EXTENSIVE VEGETATIVE SPREADING, BUT LITTLE FLOWERING
AND FRUITING; POPULATION SIZE DIFFICULT TO ESTIMATE.

General site description:

ALPINE SCREE AND DRYAS OCTOPETALA MATS, LIMESTONE SUBSTRATE; WITH
CLAYTONIA MEGARHIZA, SMELOWSKIA CALYCINA, ' ANDROSACE LEHMANNIANA,
HEDYSARUM SULPHURESCENS , KOBRESIA BELLARDII, ANTENNARIA AROMATICA,
ARCTOSTAPHYLOS UVA-URSI, SAXIFRAGA BRONCHIALIS, DOUGLASIA MONTANA.

Land owner/manager:

LEWIS & CLARK NATIONAL FOREST, ROCKY MOUNTAIN RANGER DISTRICT

Comments :

VOUCHER-SHELLY, J.S. (1609) & L.A. SCHASSBERGER, NY, 1989.

Information source:

SHELLY, J.S. 1989. FIELD SURVEYS IN TETON COUNTY, 7-10, 21-23, AND
2 8-30 AUGUST.

Montana Natural Heritage Program

MONTANA

34

U.S.G.S. Mount Wright Quadrangle (7.5')
Astragalus molybdenus

MONTANA

35

U.S.G.S. Mount Wright Quadrangle (7.5')
As tragalus molybdenus

MONTANA

36

U.S.G.S. Our Lake Quadrangle (7.5')
Astragalus molybdenus

MONTANA

37

U.S.G.S. Mount Wright Quadrangle (7.5') - TOP
U.S.G.S. Our Lake Quadrangle (7.5') - BOTTOM

As tragalus molybdenus

38

VII. PHOTOGRAPHS

39

A. Astragalus molvbdenus - plant with flowers and early
fruits (Our Lake (002) site).

^•3»

40

B. Astragalus molybdenus - plant in fruit (Our Lake (002)
site) .

41

C. Astragalus molybdenus - habit,

42

D. Astragalus molybdenus - habitat (Teton Ski Area Peak
(003) site) .

43

E. Astragalus molybdenus - habitat; note areas of stabilized
scree.

44

F. Astragalus molybdenus - habitat; note areas of stabilized
scree.

45

G. Astragalus molybdenus - habitat (Teton Ski Area Peak
(003) site) .

MONTANA
STATE

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