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Montana Field Guides

Low Milkweed - Asclepias pumila


Global Rank: G5
State Rank: S3S4
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value: 5

External Links






State Rank Reason (see State Rank above)
Asclepias pumila is found scattered through half of eastern Montana.
  • Details on Status Ranking and Review
    Low Milkweed (Asclepias pumila) Conservation Status Review
    Review Date = 11/14/2016
    View State Conservation Rank Criteria
    Range Extent

    ScoreF - 10,000 - 100,000 individuals

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    Number of Populations

    ScoreB - 6 - 20

    Number of Occurrences or Percent Area with Good Viability / Ecological Integrity

    ScoreU - Unknown

    Environmental Specificity

    ScoreC - Moderate. Generalist or community with some key requirements scarce

    Long-term Trend

    ScoreU - Unknown

    Trends

    ScoreU - Unknown

    Threats

    ScoreU - Unknown

    CommentThreats: Unknown/undetermined.

    Intrinsic Vulnerability

    ScoreC - Not intrinsically vulnerable

 
General Description
Plants: Rhizomatous. Stems simple or branched at the base, 5–20 cm. Herbage glabrous to puberulent (Lesica 2012).

Leaves: Leaves crowded, alternate and spiraling tightly around stem, or whorled near the stem's base (McGregor et al. 1986); blades erect or spreading, filiform, 1–5 cm long (Lesica 2012), 0.5-1(1.5) mm wide, leathery, apex acute; margins closely rolled under; base sessile and narrowly acute (McGregor et al. 1986).

Inflorescence: 1 to many umbels in axils of upper leaves (McGregor et al. 1986), each with 5 to 20 flowers; peduncles 5–10 mm in length (Lesica 2012); pedicels threadlike, puberulent, and 4-12 mm in length (McGregor et al. 1986).

(P. Lesica's contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)

Phenology
Flowers July-September (McGregor et al. 1986).

Species Range
Present
 


Range Comments
MT, ND south to NM, TX and IA (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Summary of Observations Submitted for Montana
Number of Observations: 20

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Gypseous or stony calcareous soils (McGregor et al. 1986) of grasslands and plains (Lesica 2012).

(P. Lesica's contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)

Reproductive Characteristics
Flowers: Flowers 5–8 mm high; sepals villous, ca 2 mm long (Lesica 2012), green or shaded with purple; petals white or tinged with pink or yellow-green, particularly on the outer surface, oval to elliptic (McGregor et al. 1986), glabrous, 3–4 mm long; gynostegium greenish-white, glabrous, 1–1.5 mm high (Lesica 2012), stipitate; column 0.6-1.1 mm high and 0.7-0.9 mm in width (McGregor et al. 1986); hoods 1–2 mm in length, oblong (Lesica 2012), upright, connected near base, widely rounded at apex, margins smooth (McGregor et al. 1986); horns exserted (Lesica 2012), arching above head of anther, 1.5-2 times the length of hood; corpusculum about 0.2 mm in length; pollinia about 0.8 mm in length (McGregor et al. 1986).

Fruit: Follicles erect to ascending, fusiform, smooth, puberulent, 4–8 cm long (Lesica 2012), 6-8 mm thick; pedicels straight to sharply bent; seeds 4-6 mm in length, ovate, with a tuft of soft white to tan hairs (coma) 12-26 mm in length (McGregor et al. 1986).

(P. Lesica's contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)

Management
This species is toxic to farm animals (McGregor et al. 1986).

References
  • Literature Cited AboveLegend:   View Online Publication
    • Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • McGregor, R.L., coordinator, and T.M. Barkley, R.E. Brooks, and E.K. Schofield, eds.: Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, KS: Univ. Press Kansas. 1392 pp.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Britton, N. L. and A. B. Brown. 1913. An Illustrated Flora of the Northern United States, Canada, and the British Possessions. 2nd Edition in 3 Volumes. New York, NY: Charles Scribner's Sons. B13BRI01PAUS.
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Citation for data on this website:
Low Milkweed — Asclepias pumila.  Montana Field Guide.  .  Retrieved on , from