CYPBRDS OYPERACE^ 687 



2 Dnllchlum Inflorescence axillary: perianth of 6-9 bristles: style 

 persistent. 



+■ *■ Spikelets many-flowered, not flattened, the scales imbricated 

 all around. 



*♦ Styles not enlarged fet base. 



3 Scirpns Spikelets solitary or clustered, or in a compound umbel, 



involucrate : perianth of few barbed persistent bristles or wanting. 



4 Erlophornm Spikelets solitary or few, involucrate : |ierianth of numer- 



ous long silky naked bristles : stamens 1-3. 



6 Hemicarpha Low annuals: spikelets solitary or few, in a sessile 

 apparently lateral cluster : perianth a minute hyaline bractlet between 

 each flower and the rachis: stamen only one. 



■*•■ ** Style enlarged at base. 



6 Eleocharis Spikelet solitary and terminal upon a leafless terete stem: 



perianth of 3-9 retrorsely barbed bristles, or wanting : stamens 3 : 

 base of the style persistent. 



7 Stenophyllns Low annuals, the stem leafy at base ; spikelets in an 



involucrate umbel : perianth none : stamens 1-3. 



* * Spikelets polygamous, few-flowered, ovoid, the scales imbricated 

 all around, only the terminal one fertile. 



8 Rtaynchospora Stems leafy: spikelets variously clustered : perianth 



of 9-12 retrorsely .barbed bristles: acbenes lenticular, beaked by the 

 persistent base of the style. .< 



* » * Flowers monoecious, in the same or distinct spikelets, or 

 dicecious: pistillate flowers enclosed in an inflated sac-like persistent 

 perigynium. 



9 Carex Spikelets solitary, spicate or panicled : perianth wholly want- 



ing, or of^a single short bristle at the base of the ovary. 



1 OYPEEUS L. Sp. 44. 



Perennial or annual herbs with mostly triangular nearly naked 

 simple stems, alternate nearly radical leaves and perfect flowers 

 in few- to many-flowered mostly flattened spikelets, the concave 

 more or less carinate scales in 2 raiiks. Perianth wholly wanting. 

 Stamens 1-3. Style not thickened at base, 2-3-cleft, deciduous. 

 Achenes lenticular or 3-angled, not beaked, smooth or nearly so. 



C. inflexns Muhl. Gram. 16. C. ariBtatus Bwckl. in part. Annual : 

 stems slender or almost filiform, diffusely branched from the base, ,1-fi i,nches 

 high: leaves a line wide or less, about equalling the stem: those of the involu- 

 luore 3-3, exceeding the inflorescence: umbel sessile, 1-3-rayed: spikelets 

 linear-oblong, 6-10-flowered, 3-3 lines long: scales bright brown, lanceolate, 

 rather- flim, strongly several-nerved, tapering into a long recurved awn, fall- 

 ing from the rachis at maturity: stamens 1: style 8-cleft: rachis naiTOwly 

 winged, the wings persistent: achenes 3-angled, dull brown, naiTOwly obovoid 

 or oblbng. obtuse, mucronulate. In wet sandy soil; California to British 

 Columbia and the Eastern States. 



C. acamittatns Torr. & Hook. Ann. Ly(i, N. Y, iii, 436. Annual: 

 stems very slender, tufted, 2-15 inches high:. leaves light green, usually less 

 than a line w^ide, often equalling the stem, those of the involucre much 

 elongated: umbel 1-4-rayed, simple,'ray8 short: spikelets flat, ovate oblong, 



