Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
62. Cyperaceae, the Sedge Family
7. Fimbristylis Vahl
2. Fimbristylis puberula (Michx.) Vahl
Perennial with slender, stiff culms 2-7 dm tall, solitary or in small
tufts, sometimes bulbous at the base, with short, slender to thick rhizomes.
Leaves shorter than the culm; blades flat to involute, 0.5-3 mm
wide; ligule a line of short hairs or incomplete to absent. Inflorescence
umbellate or some branches forked, subtended by 2 or 3 foliaceous bracts, the
longest of these shorter than to exceeding the inflorescence; pedicels
slender, ascending to spreading; spikelets few to many, ovoid to ovoid-cylindric,
5-10 mm long; scales pale to dark brown, broadly ovate, mostly 3-3.5
mm long, broadly rounded at the apex, often with a short awn or mucro, scarious
and sometimes short-ciliate on the margins, firm, shiny and often finely striate
on the back, the lower scales sometimes puberulent; stamens (2)3; styles
bifid, fringed with fine hairs below the branches. Achenes pale brown,
lenticular, 1.2-1.8 mm long, reticulate between fine longitudinal lines on the
convex faces, the straplike filaments often adherent to the achene base. Jun--Aug.
Wet meadows, shores and moist to dry prairies, often where sandy; occasional
in NE; (NJ to MI and NE, s to FL, TX and NM). F. castanea (Michx.) Vahl,
F. caroliniana (Lam.) Fern., F. drummondii Boeckl.
Most plants of the northern plains are var. interior (Britt.) Kral,
characterized as follows: Culms rarely bulbous at the base, with numerous
slender, twisted, orangish rhizomes produced from the rather soft, tufted
base. Longest involucral bract usually surpassing the inflorescence;
spikelet scales glabrous.
From e NE we have a few collections of var. puberula: Culms
bulbous at the base, arising from a thick rhizome and clothed by the firm,
fibrous sheaths of old leaves. Longest involucral bract usually much
shorter than the inflorescence; spikelet scales short-ciliate.
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R. & S.
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