288 



GRAMINEAE. 



VOL. I. 



105. SITANION Raf. Journ. de Phys. 89: 103. 1819. 



Tufted grasses, with flat or involute leaf-blades, and a terminal dense spike with the 

 rachis articulated and readily breaking up. Spikelets numerous, in 2's or 3's at each node, 

 2-5-flowered; empty scales entire or divided, the divisions extending often to the base, the 

 scales or their divisions bearing long slender awns ; palet 2-keeled. Stamens 3. Styles' dis- 

 tinct, short. Stigmas plumose. Grain adherent to the palet. [Greek, a kind of food.] 



Species 12, or perhaps more, mainly natives of the western United States. Type species: 

 Sitanion elymoides Raf. 



i. Sitanion elymoides Raf. Long-bristled Wild 

 Rye. Fig. 699. 



Sitanion elymoides Raf. Journ. Phys. 89: 103. 1819. 



Ely mus Sitanion Schultes, Mant. 2: 426. 1824. 



Ely mus elymoides Swezey, Neb. Fl. PI. 15. 1891. 



S. brevifolium J. G. Smith, Bull. U. S. Dep. Agr. Agrost. 



18 : 17. 1899. 

 S. longifolium J. G. Smith, Bull. U. S. Dep. Agr. Agrost. 



18: 18. 1899. 



Culms i-2 tall, erect. Sheaths smooth or rough, 

 sometimes hirsute, usually overlapping, the upper one \ 

 often inflated and enclosing the base of the spike; 

 blades 2'-?' long, $"-2" wide, often stiff and erect, 

 usually rough, sometimes hirsute, flat or involute; 

 spike 2'-6' in length ; spikelets i-5-flowered ; empty 

 scales entire, awl-shaped ; flowering scales 4"-s" long, 

 5-nerved, scabrous, bearing a long slender divergent 

 awn ii'-3' in length, the apex of the scale sometimes 

 2-toothed. 



In dry soil, Wyoming to western Missouri, Texas, Ari- 

 zona and Nevada. July-Aug. 



106. ELYMUS L. Sp. PI. 83. 1753. 



Tall grasses, with usually flat leaf-blades and dense terminal spikes. Spikelets 2-several- 

 flowered (rarely i-flowered), sessile, usually in pairs, occasionally in 3's or more, in alter- 

 nate notches of the continuous or jointed rachis, the empty scales forming an apparent invo- 

 lucre. to the cluster. Two lower scales empty, attached obliquely, narrow, acute or awned, 

 entire ; flowering scales shorter, rounded on the back, 5-nerved, usually bearing an awn. Palet 

 a little shorter than the scale, 2-keeled. Stamens 3. Styles very short, distinct. Stigmas 

 plumose. Grain sparsely hairy at the summit, adherent to the palet. [Greek, to roll up, 

 referring to the involute palet.] 



About 40 species, natives of temperate regions. Type species : Ely mus arenarius L. 

 Empty scales of the same length, equalling or longer than the flowering scales. 

 Spikelets appressed ; spike narrow, slender. 

 Flowering scales glabrous. 



Blades less than 3" wide, rarely exceeding 2" ; spikelets i-3-flowered, the flowering scales 



4"-S" long, with an awn as long or a little longer. i. E.Macounii. 



Blades 3"-;" wide ; spikelets 3-6-flowered, the flowering scales s"-6" long, with an awn 



one and a half to twice as long. 2. E. glaucus. 



Flowering scales appressed-hispid. 3- E- vulpinus. 



Spikelets spreading ; spike broad and stout. 



Flowering scales muticous, or with awn rarely over a quarter as long as the scale. 



Spikelets villous. 4- E. arenarius. 



Spikelets glabrous. 



Empty scales subulate. 5- E. condensatus. 



Empty scales broad and flat, indurated at the base. 6. E. curvatus. 



Flowering scale with an awn as long as itself or longer. 

 Empty scales linear-lanceolate to linear. 



Empty scales manifestly indurated, usually curved or bowed at the white base. 



Awn rarely exceeding one and a half times the length of the flowering scale ; awn 



of the empty scales usually short. 

 Flowering scales glabrous or hispidulous. 



Spike long-exserted, its own length or more, from the narrow upper sheath. 

 Plant green ; flowering scales glabrous or hispidulous ; leaf-blades lax, 



commonly exceeding 2" wide ; a plant of the interior. 7. E. jejunus. 

 Plant grey green, glaucous ; flowering scales papillose ; leaf-blades sfff, 



2" wide or less; a plant of the brackish marshes. 8. E.halophilus. 

 Spike included in the broad, inflated upper sheath. 9. E. virginicus. 



Flowering scales hirsute. i- E. hirsutigluims. 



Awn exceeding twice the length of flowering scale ; awn of empty scales very long. 

 Spikelets hirsute. " E. anstrahs. 



Spikelets glabrous or hispidulous. 12. E. glabnflorus. 



Empty scales not indurated, not white at the base, straight. 13. E. canadensis. 

 Flowering scales hirsute. 

 Flowering scales glabrous or hispidulous. 14- E. brachystachys. 



