North American Cijperacece. 281 



exterior ones, free tlieir whole length in the mature spikelet, and resem- 

 bling a 2-valved perianth. Stamens 3 (2 in the superior florets). Style 

 3-cleft one third of its length; the segments revolute. Nut ovate, acute, 

 half as long as the scale, compressed-triangular, flattened on the back, 

 smooth and shining. 



Hab. Wet places, particularly on the banks of rlv^ers. 

 Pennsylvania, North Carolina and Georgia, Muhlenberg! ; 

 Delaware, Dr. Baldichi ! ; Middle Florida, Dr. ChaiJman! ; 

 New Orleans, Dr. Ins-alts ! 



The following species of Cyperus, recorded by Pursh and other -writers 

 on North American Botany, are omitted, as they either do not belong to 

 our Flora, or cannot be identified by the imperfect descriptions of the 

 authors who have noticed them. 



1. C. AUTUMNALis, PursJi, fl. 1. p. 51. (excl. syn.) 



Along the margins of ponds and ditches. Virginia and Carolina. 

 —Pursh. 



This species was founded by Vahl on the Scirpus autumnalis, Rotlh. 

 and Linn., which is a species of TrichdostyLis {Scirpus L.) The Cyperus 

 complanatus, Willd. and Scirp. foliis pusillus autumnalis, &c. Clayt. 

 772, which Vahl refers to his C. autumnalis, likewise belong to a spe- 

 cies of Trichelostylis (T. complanata, N. ah E.) The C. juncoides of 

 Lamk., another of Vahl's synonyms, is an East Indian species. Pursh's 

 plant seems to be C. articulatus. 



2. C. TENUiFLORUS, Piirsli, fl. 1. p. 52. (not of Roitb., Vahl, Elliott, 

 and others.) 



In wet fields in Carolina and Georgia, Pursh. 



Pursh has probably confounded some other species with the C. tenui- 

 Jlorus of Rottboell. 



3. C.FiLiciNus. Spikeletslinear-lanceolate, somewhatremote, loosely 

 imbricated ; involucre 3-leaved, longer than the umbel, and, as also the 

 leaves, lax. Culm half a foot high, filiform, acutely angular, as long as 

 the leaves, lax. Leaflets of the involucre resembling the leaves; involu- 

 cels wanting. Ochrece truncate. Umbel somewhat compound, 3 — 4- 

 rayed ; rays an inch or more in length ; partial umbels 3-rayed ; the rays 

 very short. Spikelets 4 — 8, scarcely half an inch long, 12-flowerecf, 



