Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
62. Cyperaceae, the Sedge Family
5. Elocharis R. Br. -- Spikesedge, spikerush
5. Eleocharis obtusa (Willd.) Schult. -- Blunt spikesedge
Tufted, fibrous-rooted annual 0.5-3 dm tall; culms terete, 0.5-1.2 mm
thick; sheaths green, firm, oblique at the orifice. Spikelets ovoid to
lance-cylindric, 4-18 mm long, 2-4 mm thick; sterile basal scales 1 or
2; floriferous scales many, brown on the sides, with a green or pale
midvein, scarious on the margins, rounded at the tip, 1.7-2.5 mm long; perianth
variable, of up to 6(7) brown bristles, shorter than to exceeding the achene,
or the perianth lacking; styles bifid or trifid or both in the same spikelet.
Achenes light green to brown, shiny, biconvex, 0.8-1.3 mm long excluding
the tubercle, 0.7-1 mm wide; tubercle flat, triangular, sharp-edged,
0.1-0.3 mm high, tightly fitting to the broad, flat summit of the achene. Jun--Sep.
Exposed mud in marshes, ditches, streams and temporary ponds, often where disturbed
by cultivation; occasional; (Widespread over most of N.Amer. and Eurasia). E.
ovata (Roth) R. & S., E. engelmannii Steud.
Plants of this region belong to var. ovata (Roth) Drapalik and Mohlenbrock.
Previous Section -- Eleocharis macrostachya Britt.
Return to Family -- Cyperaceae - The
Next Section -- Eleocharis parvula (R. & S.) Link
ex Buff. & Fingerh. -- Dwarf spikesedge