Aquatic and Wetland Vascular Plants of the Northern Great Plains
62. Cyperaceae, the Sedge Family
3. Cyperus L. -- Galingale, umbrella sedge
7. Cyperus esculentus L. -- Yellow nut-sedge, chufa
Robust tuberiferous perennial 20-60 cm tall; culms arising singly, stout,
erect; hard nutlike tubers produced at the ends of underground scaly stolons
(these evident even if no tubers are collected). Leaves shorter than
to surpassing the culms, the blades 3-12 mm wide, the involucral bracts
similar to the leaves, often greatly exceeding the inflorescence. Spikelets
pinnately arranged on an elongate rachis to form several to many rather open,
cylindrical spikes, a few of the spikes sessile and others extended on rays
mostly 2-8(15) cm long; spikelets 4-12 mm long; scales overlapping
in the spikelets, (1.8)2-2.5 mm long, stramineous to pale brown, with 7-13 well-distributed,
often faint nerves; rachilla persistent, the scales and achenes dropping
off separately, eventually the entire rachilla falling as a whole; stamens
3; styles trifid. Achenes tan to pale brown, trigonous, ellipsoid
to obovoid, 1.2-1.5 mm long. Late Jul--Sep. Shores, stream banks and other wet
places; uncommon in the e parts of ND and SD, more common s; (Pantropical and
temperate, in N.Amer. from ME to ND, s to S.Amer., sparingly intro. to the w;
common as a lawn weed in se U.S.).