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 zs 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. 

 Elymus Sitanion Schultes, Mant. 2: 426. 1824. 

 Elymus elymoides Swezey, Neb. Fl. PI. 15. 1891. 

 S. brevifoiium 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"-5" 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 : Elymus 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"-$" 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- arenarius. 



Spikelets glabrous. 



Empty scales subulate. S- 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 st'ff, 



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. 10. E. hirsutiglumis. 



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



Spikelets hirsute. 

 Spikelets glabrous or hispidulous. 



Empty scales not indurated, not white at the base, straight, 

 Flowering scales hirsute. 

 Flowering scales glabrous or hispidulous. 



E. anstrahs. 



1 2. E. glabriflorus. 



13. E. canadensis. 



14. E.brachystachys. 



