Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
62. Cyperaceae, the Sedge Family
11. Scirpus L. -- Bulrush
11. Scirpus saximontanus Fern.
Small, tufted annual 1.5-4 dm tall; culms several to many, terete or
essentially so, grooved when dried. Leaves 1 per culm, mainly basal,
sheathing only or with a short blade mostly less than 1(-4) cm long; principal
involucral bract prominent, erect, resembling a continuation of the culm,
3-15 cm long; other involucral bracts none or weakly developed, shorter
than to surpassing the inflorescence, projecting laterally below the spikelets.
Inflorescence appearing lateral, comprised of 3-8 spikelets, all essentially
sessile or some in clusters of 2-3 at the tips of short pedicels to 1 cm long;
spikelets ovoid to oblong-cylindric, 4-13 mm long, 2.5-3 mm thick; scales
whitish to eventually dull yellowish-brown, with a prominent green midrib, scarious-margined,
rotund-ovate, strongly convex dorsally, 2.5-3 mm long, mucronate or the lower
scales with an awn to 1 mm long; perianth bristles absent or otherwise
variable; stamens 3, the straplike filaments often adherent to the achene;
styles trifid. Achenes light green to eventually dark brown, strongly
trigonous, obovoid, 1.4-1.8 mm long, conspicuously cross-ridged on the surface,
short-beaked. Aug--Sep. Muddy shores and flats where previously flooded; occasional
in SD and NE; (IA and SD, s to MO, TX and into n Mex.). S. supinus L.
var. saximontanus (Fern.) Koyama.
Reports of S. hallii A. Gray and S. smithii A. Gray in the
region are very likely based on the above. Both are similar to S. saximontanus
but have bifid styles and lenticular (plano-convex rather than strongly trigonous)
achenes. S. hallii has the achenes cross-ridged like those of S.
saximontanus, whereas the achenes of S. smithii are smooth.
Previous Section -- Scirpus pungens Vahl -- Three-square
Return to Family -- Cyperaceae - The
Next Section -- Scirpus tabernaemontani Gmel.
-- Softstem bulrush