North American Cyperacea. 267 



of the umbel slender, 1 — 2 inches long, somewhat erect. Involucre 

 2 — '3 times as long as the umbel. Ochreee with a short mucronate tip. 

 Spikelets 16 — 24 on each ray, scattered along its upper half. Scales 

 membranaceous, nerved, not mucronate. Stamens 3. Style 3-cleft 

 nearly to the base. Nut light brown, obtusely angular in front. 



Hab. Near New Orleans, Hooker! 



Obs. For specimens of this distinct species of Cyperus, I 

 am indebted to my most liberal friend Dr. Hooker, who received 

 them either from Mr. Drummond, or Mr. Teinturier. In its 

 slender and wiry cespitose culms, which are swollen at the base, 

 this species resembles C. mariscoides Sf C. Grayii, but in its 

 alternate spikelets it is more nearly related to C. repens of 

 Elliott. 



Involucre mostly 3-leaved. Spikelets three-fourths of an inch long, 

 linear, somewhat obtuse when mature, for the most part distichously 

 arranged on the common rachis ; the lowest ones frequently geminate or 

 fasciculate. Scales yellowish, nerved, at length distinct at the point. 

 Interior scalet lanceolate, adnate.thyaline, Stamens 3. Style sometimes 

 unequally 3-cleft. Nut acute. 



1 1 Spikelets aggregated in a capitate or subumbellate manner 

 on the summit of the rays. 



20. Cyperus filiculmis, VahL 



Culm triangular, tuberous at the base, assurgent ; leaves 

 linear; umbel simple, of 1 — 2 divaricate rays, or wanting; 

 ochreae pointless; heads globose, dense, composed of 15 or 20 

 spikelets; spikelets linear-lanceolate, rather convex, 6 — 10- 

 flowered ; rachis naked ; scales loose, ovate, obtuse or emar- 

 ginate, slightly mucronate, scarious on the margin ; nut obovate- 

 triquetrous, with a short acuminate point. 



