SEDGE FAMILY 



41 



6. FIMBRISTYLIS Vahl. l. F. interior. 



7. ERIOPHORUM L. Cotton-grass. 



Spikelets solitary; involucre wanting. 

 Plant stoloniferoiis. 



Glumes purplish-brown with narrow, pale margins. 



Glumes purjilish-brown with white, broad margins. 

 Plant tufted, not stoloniferous. 



Upper sheaths inflated; stem rough above. 



Upper sheaths not inflated; stem smooth. 

 Spikelets several, subtended by foliaceous bracts. 

 Leaf-blades triangular-channeled throughout. 

 Leaf-blades flat, at least below the middle. 



Midrib of the glumes not prominent at the tip of the glume. 



Midrib of the glumes prominent to the very tip. 



8. LEUCOCOMA Ehrh. Alpine Cotton-grass. i. L. alpina. 



9. SCIRPUS L. Bulrush, Club-rush, Tule. 

 Involucre of a single bract or wanting. 



Spikelets soUtary, rarely two together; plants tufted (except No. .5). 



Annuals; stamens 2; bristles none. 1. S. coloradensis. 



Perennials, with rootstocks. 



Involucre none. 2. S. pauciflorus. 



Involucre present, consisting of one erect bract. 



Bract scarcely exceeding the spikelet, often shorter; bog plants. 



Bristles 6, longer than the achenes. 3. S. caespitosus. 



Bristles none. 4. S. pumilus. 



Bract at least twice as long as the spikelet; aquatic plants. 



5. S. subterminalis. 

 Spikelets normally more than one, usually several, sometimes numerous. 

 Spikelets few, 1-12, appearing lateral, in a single capitate cluster. 



Annuals, with fibrous roots, tufted; achenes dark, transversely wrinkled. 

 Spikelets obtuse; achenes plano-conve.x. 6. S. Hallii. 



Spikelets acute; achenes 3-angular. 7. S. sazimontanus. 



Perennials, with rootstocks; achenes plano-convex, obovate. 

 Stem sharply 3-angled. 



Spikelets acute; bracts long; glumes awned. 8. S. americanvs. 



Spikelets obtuse: bracts short; glumes mucronate. 9. S. Olneyi. 

 Stem terete, striate. 10. S. nevadensis. 



Spikelets numerous in small clusters of 1-7, arranged in compound umbels; per- 

 ennials with stout rootstocks. 

 Style 2-cleft; achenes obovate and plano-conve.x, brown. 



Achenes 2 mm. long, nearly as long as the glumes; spikelets ovoid. 



11. S. validus. 

 Achenes 3 mm. long, distinctly shorter than the glumes; spikelet oblong- 

 cylindric. 12. S. occidenlalis . 



Style 3-cleft; achenes obcordate, 3-angled, yellowish. 13. S. heterochaetus. 



lnvoluci"e of two or more leaves with flat blades; perennials, with rootstocks. 



Spikelets 3-10, capitate, relatively large. 14. 5. paludosus. 



Spikelets numerous, in compound umbels or in umbellate heads, relatively small. 

 Bristles downwardly barbed, not much exceeding the fruit. 



Style-branches 2; achenes plano-convex; bristles mostly 4. 1.5. S. microcarpus. 

 Style-branches 3; achenes oblong, 3-angular; bristles 6. 



Plant dark green; glumes acute; achenes pale brown. 16. .S. atronrens. 

 Plantpale;glumesrough-awned:aclienesstraw-colored. 17. S. pallidus. 

 Bristles 6, smooth, much exceeding the glumes at maturity; achenes 3-angled, 

 whitish. 

 Spikelets all sessile; glumes brown. 18. S. cyperiniis. 



Spikelets mostly pediceled; glumes mostly greenish black. 19. S. alrocinctus. 



10. HEMICARPHA Nees & Arn. l. H. aristulata. 



11. KOBRESIA Willd. l. K. bipartiia. 



12. ELYNA Schrad. l. E. Bellardi. 



13. CAREX (Rupp.) L. Sedge.* 



Spike one, androgynous; perigynia glabrous, thin, not margined or triangular, beaked; 

 style withering, not continuous with the achene; stigmas tiiree. 

 Pistillate scales oensistent; perigynia not stipitate, not becoming reflexed. 

 Spike linear or linear-oblong; perigynia not inflated. 1. Nardinae. 



Spike orbicular to short-ovoid; perigymia inflated. 2. Infi^tae. 



Pistillate scales deciduous; perigynia stipitate, at least the lower reflexed at maturity. 



3. Athrochlaenae. 

 Spikes one to many; if one, plant not as above. 



Achenes lenticular and stigmas two; lateral spikes sessile; terminal spike partly 

 pistillate, or if staminate, the lateral spikes short, or heads dioecious. 

 Spike one. 



Spike orbicular to short-ovoid. 4. Capitat.^^e. 



Spike linear. 5. Dioicae. 



