North American Cyperacece. 249 



B. Without a Perigynium. 

 t SpiJcelets many-flowered. 



2. CYPERUS, Linn. 



Spikelets with the scales distichously imbricated. Rachis 

 generally margined with the adnate persistent interior scales. 

 Stamens 2 — 3, deciduous. Style 2 — 3-cleft, deciduous. 

 JVuT compressed or triangular. — Culms mostly triangular (rarely 

 tertte), simple, leafy at the base; corymb terminal, simple or 

 compound ; rays more or less elongated, ochreate at the base. 



Cyperus, Linn.; ''Juss. gen. p. 27; Lam. ill. t. 38; Roem, 

 '&f Schidt. gen. 183; R. Brovm, iirodr. 1. p. 212 ; Lestih. ess, 

 p. 30. no. 23 ; N. ah Esenb. in Linnaa, 9. p. 283 ; Nutt. 

 gen. 1. p. 34. 



Pycreus, P. de Beauv. in Lestib.ess. p. 28. 7io. 17; N.ab 

 Esenh. in Linnaa, I. c. 



Papyrus, A. du Petit-Thouars ; Kunth, syn. 1. p. 148; 

 Lestih. ess. p. 31. no. 25 ; N. ah Esenh. in Wight's contrih. p. 

 69, ^in Linncea, 9. p. 286. 



Torreya, Rajin. nov. gen. in jour, de phys. 89. p. 105. 



The genera Pycreus and Papyrus of several late writers on 

 Cyperaceae appear to differ too little from Cjperus to be sepa- 

 rated from that genus. The diagnostic character of the former 

 is the compressed nut and 2-cleft style, the genuine Cyperi 

 having a triangular nut and trifid style ; but the difference can 

 hardly be regarded as of generic importance. Papyrus has the 

 two interior scales (appendices, Meyer; perianthium bipale- 

 aceum, Lestih.) separated from the rachis, either throughout their 

 whole length or at their tips ; but this character exists in several 

 genuine species of Cyperus, especially in the mature spikelet; 

 and in many others, the interior scales are very conspicuous, 

 though inseparably united with the rachis. C. A. Meyer, (in the 

 Mem. de VAcad. Imp. de St. Petersb. VI. sir. t. 1. p. 202. t. 3. ff. 



