GRASS FAMILY 103 



27. E. flavescens Scribn. it Smith. Stem 6-10 dm. high, ghibrous, or pubes- 

 cent jiLst below tlie notlcs; leaf-bhides 2-4 dm. long, 4-8 mm. wide, smooth 

 beneath, scabrous or strigulose above; spike 1-2 dm. long, yellowish; spikelets 

 3-6-flowered, 1-2 cm. long; lemma 1()-12 mm. long, mucronate or awn-pointed. 

 Sand: Wash. — Ida. — Ore. Son. Jl-Au. 



28. E. innovatus Beal. Stem smooth, or pubescent just below the nodes; 

 loaf-blades rather rigid, 5-18 cm. long, 2-8 mm. wide, scabrous on the margins 

 and nerves beneath; spike 4-10 cm. long; spikelets 3-6-flowered, 10-15 mm. 

 long; lemma densely pubescent, u.sually villous, 8-10 mm. long; awns 2-4 mm. 

 long. E. Brownii Scribn. <fe Smith. Hills: Sask. — S.D. — Wyo. — B.C. Sub- 

 mont. Je-Au. 



78. HYSTRIX Moench. 



Perennials, with rootstocks and terminal spikes. Spikelets in pairs or S's, 

 spreading, 2-several-flowered ; rachilla articulate below the lemmas. Empty 

 glumes in the lowest spikelets subulate, minute, elsewhere wanting. Lemma 

 lanceolate, rigid, convolute, rounded on the back, awned. Styles very short; 

 stigmas plumose. Grain oblong, adherent to the palet. 



1. H. Hystrix (L.) Millsp. Stem 6-12 dm. tall; leaf-blades 1-2.5 dm. long, 

 6-12 mm. wide, smooth beneath, scabrous above; spike 7-18 cm. long; spikelets 

 at length spreading. 8-12 mm. long, exclusive of the awns; lemma 8-12 mm. 

 long, acuminate; awn about 2.5 cm. long. Asprella Hystix Willd. Rocky woods: 

 N.B.—Ga.— Neb.— Sask. Plain. Je-Jl. 



Family 13. CYPERACSAE. Sedge F.\mily. 



Gras.s-like or rush-like plants, with mostly solid stsms. Leaves 3-ranked, 

 with closed sheaths and narrow blades. Flowers perfect or unisexual, in 

 spikelets; bractlets (glumes or scales) 2-ranked or spirally arranged. Peri- 

 anth composed of bristles, a sack-like organ (perigynium), or wanting. 

 Stamens usually 3, rarely I or 2, or more than 3; filaments slender; anthers 

 2-celled. Gynoecium of 2 or 3 united carpels, but ovary 1 -celled and I- 

 ovuled; .stigmas 2 or 3. Ovules anatropous, erect. Fruit an achene; endo- 

 sperm mealy. 



Flowers all perfect, or at least one ia each spikelet perfect. 

 Glumes of the spikelets 2-ranked. 



Perianth represented by bristles; inflorescence axillary. 1. DULICHIUM. 



Perianth wanting; spikelets in terminal, solitary or umbellate heads. 



2. Cyperus. 

 Glumes of the spikelets spirally imbricate. 



Base of the style persistent as a tubercle on the achene. 



Basal empty Klumes several. .3. RYNCHOSPOR.\.. 



Basal empty t;liimes waiithit^, or 1 or 2. 



Spikelet ss(iliiar.\ ;steiu leafless; bristles usually present. 4. Eleoch.\ris. 

 Spikelets several or numerous ; stem leafy; bristles none. 5. Stenophyllus. 

 Base of the stjie not persistent as a tubercle. 



Base of the style swollen ; bristles none. 6. Fimbristylis. 



Base of the style not swollen; bristles usually present. 

 Flowers without any inner scales. 



Bristles much elongating in frr.it, silky. 



Bristles 6, but each 4-6-cleft to near the base, therefore appearing 



numerous. 7. Eriophorum. 



Bristles <>, simple, crisp. 8. Leucocom.v. 



Bristles short, or little elongating, rarely wanting. 9. SciRPUS. 

 Flowers with a small inner scale between the flowei and the rachis. 



10. Hemic.\rpha, 

 Flowers monoecious or dioecious. 



Achenes not enclosed in a perigynium. 



Spikes several, clustered ; glumes subtending a single flower. 11. Kobresia. 

 Spikes soUtary ; glimies subtending 2 flowers. 12. Er.YNA. 



Achenes enclosed in a perigynium. 13. ('AREX. 



1. DULiCHIUM L. C. Rich. 



Tall perennials, with rootstocks and hollow jointed stems, leafy to the top. 

 Leaves 3-ranked. Spikelets in axillary, simple or compound spikes, flat, linear, 

 many-flowered; glumes 2-ranked, carinate, conduplicate, decurrent on the 



