E-Flora BC: Electronic Atlas of the Flora of British Columbia

Sporobolus compositus (Poir.) Merr. var. compositus
rough dropseed (composite dropseed)
Poaceae (Grass family)

Introduction to Vascular Plants
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Distribution of Sporobolus compositus var. compositus
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Species Information

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Perennial, strongly tufted grass from fibrous roots; stems nearly or quite solid, longitudinally grooved, smooth, usually 60-100 cm tall.
Sheaths open, smooth or soft-hairy; blades usually in-rolled, tough, 1-4 mm wide, mostly soft-hairy above, especially near the ligules, the collars smooth or slightly hairy near the margins; ligules scarcely 0.5 mm long.
Inflorescence a narrow, spikelike panicle, up to 15 cm long, usually at least partially enclosed in the sheath, the branches erect; spikelets 1-flowered, strongly flattened; glumes blunt, the lower ones 2.5-3 mm long, the upper ones about 1 mm longer; lemmas blunt, smooth, 4-5 mm long, paleas nearly equal to the lemmas; lodicules fan-shaped, about 0.5 mm long; anthers 1.5-2.5 mm long.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Fruit/Seed characteristics:
Colour: Brown
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Mesic to dry grasslands and shrublands in the steppe zone; rare in SC and SE BC; E to PQ, NB and NS and S to ME, MA, PA, NC, GA, AL, MS, LA, TX, NM, AZ, ID and WA.

Source: The Illustrated Flora of British Columbia


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Sporobolus asper (P. Beauv.) Kunth
Sporobolus asper var. hookeri (Trin.) Vasey

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References