50 CYPERACEAE (SEDGE FAMILY) 



CYPERACEAE (SEDGE FAMILY) 



Herbs, annual or perennial; rhizomes present; stems 3-angled 

 or terete, mostly solid. Leaves attenuate, mostly basal; sheaths 

 not split. Flowers in spikes or spikelets, small, perfect or monoe- 

 cious or dioecious, in the axils of scales; scales imbricate, 

 chaffy; spikes again variously grouped unless solitary. Peri- 

 anth none or of mere bristles or scales. Stamens usually 2-3, 

 hypogynous; anthers basifixed. Ovary i -celled; ovule i; style 

 2-3-cleft. Fruit an akene, lens-shaped or somewhat 3-angled, 

 membranous or crustaceous or bony. A difficult family. Keys 

 only to the genera. (F. & R. pp. 74-89.) 



A. Akenes not inclosed in a saclike structure; flowers perfect; spikelets all alike. 

 B. Spikelets more or less flat; scales in 2 opposite rows. 



C. Stem nearly naked; leaves mostly basal; perianth none. (Gk. kupeiros = 

 the ancient name for these plants.) Cyperus (CYPERUS) 



CC. Stem with 3 distinct rows of leaves; leaves mostly on the stem; perianth of 

 6-9 bristles. W. (Gk. duo = 2, leichen = a scale; the scales of the spikelets 

 are in 2 ranks.) Dulichium arundinaceum (DULICHIUM) 



BB. Spikelets terete; scales imbricated all round. 



D. Akenes not crowned with the bulbous base of the style. 

 E. Spikelets not a cottony mass. 



F. Perennial; perianth of 06 bristles. One of these is 5. occidentalis (Tule), 

 whose stems are used for the interior of cheap life preservers. (The Latin 

 name of the Bulrush.) Scirpus (BULRUSH) 



FF. Annual; perianth of a single hyaline scale between the rachilla and the 

 akene. (Gk. hemi half, karphos = chaff; because this genus has only 

 i inner scale while most related genera have 2 or more.) 



Hemicarpha (HEMICARPHA) 



EE. Spikelets each a white to brown cottony head of hairs 1-3 cm. wide. (Gk. 

 erion = wool or cotton, phoros = bearing; referring to the cottony spikes.) 



Eriophorum (COTTON GRASS) 



DD. Akenes crowned with the persistent bulbous base of the style. 

 G. Stem leafless; spikelets solitary, terminal ; perianth bristles usually present, 

 0-12. (Gk. elos = a marsh, chairo = to rejoice; because it grows in wet 

 places.) Eleocharis (SPIKE RUSH) 



GG. Stem leafy at least at base; spikelets more than i, in an involucrate umbel. 

 H. Akene 3-angled; perianth bristles none. U. (Gk. stenos = narrow, 

 phyllon = a leaf; on account of the very narrow leaves.) 



Stenophyllus capillaris (HAIR SEDGE) 



HH. Akene lens-shaped; perianth bristles Q-IS, downwardly barbed. W. 



(Gk. rhynchos = a snout, spora = a seed ; referring to the long-beaked 



akene.) Rhynchospora alba (WHITE BEAK-RUSH) 



AA. Akenes inclosed in a saclike structure; flowers monoecious; spikes mostly of 



2 kinds. (Gk. keirein = to cut; referring to the sharp leaf -edges.) 



Carez (SEDGE) 



