290 



CYPERACEAE. 



143. C. capitata. 



144. C. nardina. 



II. Staminate flowers few, at the summits or bases of the always sessile spikes, or sometimes 

 forming whole spikes, or variously intermixed with the pistillate ; stigmas always 2 ; achene lenti- 

 cular, compressed, ellipsoid or plano-convex. Nos. 143-205. VIGNEA. 



1. STAMIXATE FLOWERS AT THE SUMMITS OF THE SPIKES. Nos. 143-173. 

 (a) Spike solitary, terminal, mostly broivn, plants often dioecious. Nos. 143-146. DIOICAE. 



Perigynia nerveless, or faintly few-nerved. 



Perigynia with a short nearly entire beak. 



Perigynia beakless, the orifice 2-toothed. 

 Perigynia strongly several-nerved on the outer face. 



Beak of the perigynium very short. 145. C. Redowskyai 



Beak slender, rough, about half as long as the body of the perigynium. 146. C. exilis. 



(b) Spikes several or many, clustered, separated or sometimes panicled. Nos. 147-151. 

 * Spikes densely aggr. gated into a globose or ovoid head, often appearing like a solitary terminal spike 



Scales ovate or ovate-lanceolate, acute or acuminate, not awned. FOETIDAE. 



Perigynia strongly many-nerved. 147. C. chordorhiza 



Perigynia faintly several-nerved. 



Culms and leaves usually curved; scales shorter than the perigynia. 148. C. incurva. 

 Culms mostly straight, erect; scales equalling the perigynia. 149. C. slenophylla. 



Scales lanceolate, awned, or long-acuminate. ARENARIAE. 



Scales 2-4 times longer than the perigynia; western species. 150. C. Douglasii. 



Scales about equalling the perigynia; introduced sea-coast species. 151. C. arenaria. 



** Clusters of spikes looser, often compound or the spikes distinctly separated (more or less 

 aggregated in nos. 170-173). Nos. 152-173. 



t Spikes yellowish or brown at maturity, often in compound or panicled clusters. Nos. 152-163. 



Nos. 152-154. VULPIXAE. 



152. C. conjuncta. 



153. C. stipata. 



154. C. Crus-corvi. 



155. C. decomposita. 



Perigynia strongly several-nerved, especially on the outer face. 

 Beak of the perigynium shorter than the body. 

 Beak of the perigynium equalling or longer than the body. 



Spikes crowded in an oblong cluster; beak 1-2 lengths of the body. 

 Spikes in a large branching cluster; beak 3-4 lengths of the body. 

 Perigynia nerveless or faintly nerved. Nos. 155-163. MULTIFLORAE. 

 Spikes very numerous in a branched decompound cluster, small. 



Spikes several or many in an oblong or narrow, simple or somewhat compound cluster. 

 Leaves i" wide or less. 



Beak of the perigynium shorter than the body; western species. 156. C. marcida. 

 Beak as long as the body; northern marsh species. 157. C. teretiuscula. 



Leaves i"-3" wide. 



Scales acuminate, cuspidate or awned. 

 Perigynia i I A"-2^" long. 



Perigynia ovate or ovate-lanceolate, the beak about as long as the body. 



158. C. alopecoidra. 

 Perigynia broadly ovate or orbicular, the beak about one-third as long as the 



body. 159. C. gravida. 



Perigynia i l A" long or less. 



Leaves as long as the culm or longer. 160. C. z 'tilpinoidea. 



Leaves shorter than the culm. 



Perigynia ovate-elliptic, the base narrowed. 161. C. .vanthocarpa. 



Perigynia lanceolate, the base truncate. 162. C. setacea. 



Scales blunt, scarious-tipped. 163. C. Sarticellii. 



ft Spikes green or greenish when mature, aggregated or separated, in simple clusters. Nos. 164- 



173. MUHLENBERGIANAE. 



Perigynia ellipsoid, nearly terete; spikes i-5-flowered, widely separated, or the upper close together. 



164. C. tend la. 



Perigynia lanceolate, ovate or roundish, compressed or plano-convex; spikes several-many flowered. 

 Spikes separated or the upper close together; perigynia mostly radiating, or reflexed. 

 Leaves H"-i'/4" wide. 



Beak of J.he perigynium one-third to one-half.as long as the body; native woodland 



species. 

 Perigynia ovate-lanceolate, \"-\%" long. 



Perigynia stellately radiating. 165. C. rosea. 



Perigynia reflexed when mature. 166. C. retroflexa. 



Perigynia narrowly lanceolate, i Ji "-2" long. 167. C. Te.vensis. 



Beak of the perigynium more than half as long as the body; introduced field species. 



168. C. muricata. 



Leaves 2} -454 wide. !6a. c. sfiarganioides. 



Spikes all aggregated or the lower separated; perigynia spreading or ascending. 



Leaves thin, lax, jr-4" wide; perigynia about 2" long. 170. C. cephaloidea. 



Leaves stiffer, #"-2" wide. 



Perigynia i" long or less, nerveless or faintly few-nerved. 



Leaves i " -2' wide; perigynia ovate. 171. C. cephalophora. 



Leaves l A"-i" wide; perigynia orbicular-ovate; southern. 172. C. LeavenwoTthii. 

 Perigynia i % long, strongly nerved (except in var. Xalapensis}. 



173. C. Mnhlenbergii. 



