260 North American Cyperacea. 



Annual. Culm 12 — 15 inches high, firm and erect, thickened and red- 

 dish towards the root, if aves commonly shorter than the culm, 3 — 4 lines 

 wide. Involucre 5 — 6-leaved, many times longer than the umbel. Rays 

 of the umbel 4 — 6, the naked part scarcely more than an inch in length, 

 mostly divided at the summit, and sometimes bearing short setaceous 

 involucels. Spikelets' much crowded on the rays, the lower ones com- 

 pound, about three-fourths of an inch long, at first compressed, but nearly 

 terete when mature. Scales of a rather firm texture, not scarious on the 

 margin, loosely imbricated, somewhat indistinctly striate. Rachis very 

 broad and thick, separating at the joints when mature. Interior scales 

 adnate, persistent, appearing like obtuse auricles, folding round the nut 

 and firmly embracing its base. Stamens 3. Style 3-cleft more than half- 

 way down. Nut whitish, somewhat acute, flattened on the back, ob- 

 tusely angled in front, puncticulate. 



Hab. Borders of salt marshes. Common in New Jersey, 

 particularly in the neighbourhood of Hoboken ; Salina, New 

 York, J. Carey!; Carolina, Michaux!; Wilmington, North Ca- 

 rolina, Mr. Curtis!; Georgia and Delaware, Dr.Baldivin; New 

 Orleans, Dr. Ingalls ! 



Obs. This plant probably grows in many parts of the 

 Atlantic States, being confounded either with C. strigosus or C. 

 erijthrorhizos. It is clearly the C. strigosus of Michaux, as I 

 have ascertained by examining his herbarium ; and he correctly . 

 describes the plant as having S7ibterete spikelets. To the C. 

 pennatMs of Lamarck (of which I possess a specimen from A. 

 de Jussieu,) it is very nearly allied, not only in general appear- 

 ance, but in the structure of the spikelets. That species, how- 

 ever, has a loose corymb, longer spikelets, slightly mucronate 

 glumes, and an oblong nut. 



13. Cyperus tetragonus, Elliott. 



Umbels many-rayed, without involucels ; spikes oblong, cy- 

 lindrical ; spikelets 3 — 5-flowered, somewhat quadrangular; 

 scales slightly mucronate ; nut oblong. 



C. tetragonus, Elliott, sk. 1. p. 71 ; Schult. mant. 2. p. 130. 



