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Montana Field Guide

Montana Field Guides

Tall Dropseed - Sporobolus compositus
Other Names:  Sporobolus asper

Species of Concern
Native Species

Global Rank: G5
State Rank: SH
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:

External Links

State Rank Reason (see State Rank above)
Known in Montana from 3 collections; a 1939 collection near Ekalaka, a 1957 collection from Fort Keogh Livestock and Range Laboratory and a 1980 collection from Bighorn County.
General Description
Perennial. Stems 30–80 cm. Leaves: blades 2–4 mm wide; throat with a tuft of hairs. Inflorescence a contracted panicle 5–15 cm long, mostly enclosed in leaf sheath. Spikelets 4–6 mm long. Lemmas 3–6 mm long (Lavin in Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Mature fruit in August.

Diagnostic Characteristics
Both S. cryptandrus and S. airoides have spikelets less than 3 mm long and more open inflorescences.

Species Range

Range Comments
Collected in Carter County; sporadic throughout most of North America (Lavin in Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 3

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



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

Open forests and grasslands on the plains.

  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Brey, C.W. 1998. Epidemiology of wheat curl mite (Aceria tosichella K.) and wheat streak mosaic virus on feral grass species and effect of glyphosate on wheat curl mite dispersal. Ph.D. Dissertation. Bozeman, MT: Montana State University. 136 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
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Citation for data on this website:
Tall Dropseed — Sporobolus compositus.  Montana Field Guide.  .  Retrieved on , from