I^</rth Ameiican Cyperacea. 249 
B. Without a Perigynium. 
t Spikeleti many-flowered^ 
2. CYPERUS, Linn. 
Spikelets with the scales distichously imbrlcatsd. Fachis 
generally margined with the adnate persistent interior scales. 
Stamens 2 — 3, deciduous. Style 2 — 3-cleft, deciduous. 
Nut compressed or triangular. — Culms mostly triangular (rarely 
terete), 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 ; Ram. 
^ Schult. gen. 183; R. Brovm, prodr. 1. p. 212 ; Lestib. ess. 
p. 30. no. 23 ; A^. ab Esenb. in Linmea, 9. p. 283 ; Nvtt. 
gen. 1. p. 34- 
Pycreus, P. de Beauv. in Lestib. ess. p. 28. no. 17; N.ab 
Esenb. in Linnceo, I. c. 
Papyrus, A. du Petit-Thouars ; Kinith, syn. 1. p. 148; 
Lestib. ess. p. 31. 7io. 25 ; N. ab Esenb. in Wight'' s contrib. p. 
69, If in Lhincea, 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 Cyperus 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, Lestib.) separated from the rachiis, 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 V Acad. Imp. de St. Petersb. VI.seY. 1. 1. p. 202. t. 3. ff. 
