GRASS FAMILY 103 



27. E. flavescens Scribn. & Smith. Stem 6-10 dm. high, glabrous, or pubes- 

 cent just below the nodes; leaf-blades 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 10-12 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' 

 leaf-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, usually villous, 8-10 mm. long; awns 2-4 mm 



long. E. Brownii Scribn. & 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 3'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. CYPERACEAE. SEDGE FAMILY. 



Grass-like or rush-like plants, with mostly solid stems. 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 1 or 2, or more than 3; filaments slender; anthers 

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

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

 sperm mealy. 



Flowers all perfect, or at least one in 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 glumes several. 3. RYNCHOSPORA. 



Basal empty glumes wanting, or 1 or 2. 



Spikelets solitary ; stem leafless ; bristles usually present. 4. ELEOCHARIS. 

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

 Base of the style 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 fruit, silky. 



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



numerous. 7. ERIOPHORUM. 



Bristles 6, simple, crisp. 8. LEUCOCOMA. 



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

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



10. HEMICARPHA. 

 Flowers monoecious or dioecious. 



Achenes not enclosed in a perigynium. 



Spikes several, clustered ; glumes subtending a single flower. 1 1 . KOBRESIA. 

 Spikes solitary ; glumes subtending 2 flowers. 12. ELYNA. 



Achenes enclosed in a perigynium. 13. OAREX. 



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 



