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Northern Prairie Wildlife Research Center

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Aquatic and Wetland Vascular Plants of the Northern Great Plains

63. Poaceae, the Grass Family

28. Sphenopholis Scribn.

1. Sphenopholis obtusata (Michx.) Scribn. -- Prairie wedgegrass

Tufted or sometimes solitary perennial 2-8 dm tall; culms slender, 0.5-1 mm thick. Leaves ascending to spreading, flat, scabrous, 1-7 mm wide; sheaths glabrous, or the basal ones puberulent; ligule white-hyaline, lacerate, 1-4 mm long. Panicle dense, contracted and spikelike, often interrupted, (1.5)5-12 cm long. Spikelets 2-flowered, 2.5-3.5 mm long, disarticulating below the glumes; glumes 1.5-2.5 mm long, scabrous on the keel, the first glume linear, 1-nerved, the second glume much broader than the first, obovate, 3- to 5-nerved; lemmas acute, 2-3 mm long, scaberulous toward the apex on the keel, 1-nerved; palea exposed, linear, about as long as the lemma, scarious. Grain light brown, elongate, flattened, 1.5-2 mm long. Late Jun--Aug. Low prairie, wet meadows, shores, stream banks and moist woods; common in the e part, becoming uncommon w; (ME to B.C., s to FL, Mex. and CA; also the W.Indies).

Two varieties of S. obtusata occur in the region. Var. obtusata, has the panicle contracted and the second glume 2/3 to fully as wide as long. Var. major (Torr.) Erdman, also known by the name S. intermedia (Rydb.) Rydb., differs in having a more lax, loosely spreading panicle and the second glume 2/5 to 3/5 as wide as long. The former is more often encountered in wet places, whereas var. major is more typical of wooded habitats.


Erdman, K. S.  1965.  Taxonomy of the genus Sphenopholis (Gramineae).
     Iowa State Coll. J. Sci. 39:289-336.
GIF- Species Photo/Drawing

Sphenopholis obtusata (from Hitchcock 1950).
GIF- Distribution Map

Map key

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Return to Family -- Poaceae - The Grass Family
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