436 North American Cijijeracect, 
CypERus RUFESCENS, Torr. ^^ HooJc. 
Culm obtusely triangular, smooth, slender ; leaves very 
narrow ; umbel simple or somewhat compound, 4 — 5-rayed ; 
involucre about 3-leaved, the longer leaves twice the length of 
the umbel ; heads composed of 40 — 50 spikelets, subglobose, 
dense ; spikelets ovate, 12 — 16-flowered ; scales ovate-lanceo- 
late, closely imbricated, acute, straight ; stamens L — 3 ; nut 
ovate, triquetrous, acuminate at each end. 
Rhizoma short, tuberous. Culm about IS inches high, less than a 
line in thickness, the sides concave. Umbel small ; rays somewhat 
erect, sometimes a little divided at the summit. Ochrece entire. Heads 
about half an inch in diameter ; the spikelets much crowded. Sjnkelets 
much compressed, somewhat acute, 2 — 3 inches long. Scales carinate, 
with a nerve on each side near the keel, somewhat coriaceous, tinged of 
a bright brownish red colour. Stamens never more than 2, and often 
solitary. Style 'S-cle[t. iYwi sharply triangular, dull, not half the length 
of the scale. 
Hab. Texas, T. Di-ummond! (Coll. I. the specimens 
not numbered.) 
Obs. Resembles C. virens,h\xi is much more slender; the 
leaves are also narrower, and the culm is smooth. 
Cyperus cyrtglepis, Torr. Sf Hool: 
Culms cespitose, slender, wiry ; umbel 3 — 5-rayed ; rays 
very unequal, erect ; involucre 3 — 4-leaved, setaceous, much 
longer than the umbel ; heads dense, subglobose ; spikelets 
broadly ovate, much compressed, 9 — 12-flowered, the florets 
distant ; scales lanceolate, acute, recurved and spreading, with- 
out nerves ; interior scales ; stamen solitary ; nut oblong, 
acute at each end, smooth, dull. 
Culm a foot or more in height, strong and wiry, sulcate. Leaves very 
narrow, nearly as tall as the umbel, channelled. U7nbel simple, rays 
