CYPERACEAE. 



43 



spikelets solitary or clustered, 1 to many-flowered; scales two- 

 ranked or in a spiral, persistent or deciduous; perianth hypogy- 

 nous, of bristles, or interior scales wanting; stamens 1-3, rarely 

 more; ovary 1-celled, 1-ovuled; style 2- or 3-cleft; fruit a lenticular 

 or three-sided akene; endosperm mealy; embryo minute. 



Flowers monoecious or dioecious, usually borne in 



separate spikes. 

 Flowers of the spikelet all, or at least one of them 



perfect; spikelets all similar. 

 Spikelets compressed; scales 2-ranked. 

 Spikelets not compressed; scales in a spiral. 



Base of style swollen, persistent as a tubercle on 



the akene. 



Base of style not swollen, deciduous or per- 

 sistent as a subulate tip. 

 Bristles present; hyaline scales none. 

 Bristles none; perianth of a single minute 



posterior scale. 



65. CAREX, 43. 



66. CYPERUS, 49. 



67. ELEOCHARIS, 50. 



68. SCIRPUS, 51. 



69. HEMICARPHA, 52. 



65. CAREX. SEDGE. 



Grass-like sedges, perennial by rootstocks; stems mostly 

 triangular; leaves 3-ranked, the upper (bracts] elongated or very 

 short, and subtending the spikes of flowers, or wanting; flowers 

 solitary in the axils of bracts (scales), monoecious or dioecious; 

 spikes either wholly staminate, or pistillate, or sometimes 

 androgynous; perianth none; staminate flowers of 3 stamens; 

 pistillate flower of a single pistil with a style and 2-3 stigmas 

 borne in the axil of a second bract (the perigynium) which com- 

 pletely encloses the akene; akene 3-angled, lenticular or plano- 

 convex. 



SECTION 1. Spikes sessile, all alike, bearing the inconspicuous staminate 

 flowers either at the base, at the top, or rarely scattered; stigmas 2; akenes 

 lenticular. Subgenus VIGNEA. 



Spikes not densely aggregated, the individual ones easily dis- 

 tinguished. 

 Perigynia wing-margined. 



Perigynia 6-7 mm. long; spikes acute. 

 Perigynia 3-4 mm. long; spikes obtuse. 



Bract present; perigynia twice as long as broad. 

 Bract wanting; perigynia as broad as long. 

 Perigynia not wing-margined. 



Spikes 10-30-flowered; perigynia straight. 

 Spikes 4-8-flowered; perigynia curved. 

 Spikes densely aggregated, the individual ones, at least the 



uppermost, distinguishable with difficulty. 

 Perigynia margined. 



Dioecious or with the staminate and pistillate flowers 

 irregularly scattered. 



C. liddoni. 



C. bebbii. 

 C. festucacea. 



C. bolanderi. 

 C. laeviculmis. 



