43G North American Cyperacea. 



CyPERUS RUFESCENS, To7T. ^ Hoolc. 



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 1 — 3 ; nut 

 ovate, triquetrous, acuminate at each end. 



Rhizoma short, tuberous. Culm about 18 inches high, less than a 

 line in thickness, the sides concave. Umbel small ; rays somewhat 

 erect, sometimes a little divided at the suinmit. Ochreee entire. Heads 

 about half an inch in diameter ; the spikelets much crow^ded. Spikelets 

 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 3-cleft. Nut sharply triangular, dull, not half the length 

 of the scale. 



Hab. Texas, T. Drummojid! (Coll. I. the specimens 

 not numbered.) 



Obs. Resembles C. vire7is, hut is much more slender; the 

 leaves are also narrower, and the culm is smooth. 



Cyperus cyrtolepis, Torr. ^ Hoolc. 



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, whh- 

 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. Umbel simple, rays 



