42 CYPERACEAE. 



64. SITANION. 



Cespitose perennials, with spike-like panicles, which readily 

 break up into segments; spikelets 2-3 at each joint of the rachis, 

 rarely solitary, 1-5-flowered; glumes subulate and entire, or 

 lanceolate and bifid, or parted into several long-awned lobes; 

 lemmas lanceolate and acute, or those of the lowest floret sterile 

 and subulate, entire with a single awn, or trifid and three-awned. 

 This genus is hardly distinct from Elymus. 



Glumes cleft or parted into 3 to many lobes; awns of lemma 8-10 



cm. long. 5. jubatum. 



Glumes entire or only 2-cleft or 2-parted. 

 Sheaths and upper leaf surfaces glabrous. 



Blades 2-5 mm. broad. 5. rigidum. 



Blades 5-7 mm. broad. 5. latifolium, 



Sheaths and upper leaf surfaces pubescent. 



Culm leaves 7-12 cm. long. S. hyslrix. 



Culm leaves 2-6 cm. long. S. velutinum. 



Sitanion jubatum J. G. Smith. Stems stout, mostly erect, 20-30 cm. high; 

 leaf blades short, flat, strigose-pubescent and somewhat hirsute, 4-8 cm. wide; 

 sheaths densely hirsute; spike 6-8 cm. long, the base enclosed in the elongated 

 upper leaf sheath; glumes 3-8-parted, each lobe bearing a slender awn 3-8 cm. 

 long; lowest floret sterile, its lemma resembling the glumes; lemma of perfect 

 florets lanceolate, 3-awned, the middle awn stout, 8-10 cm. long, the lateral 

 ones slender and usually snorter. Common in dry ground. 



Sitanion rigidum J. G. Smith. Stems 10-20 cm. high; leaf blades green 

 or slightly glaucous, rigid, 2-5 mm. wide, flat or at length involute; spike 

 green, 2-8 cm. long, erect or nearly so, often included at base in the upper 

 sheath; glumes or glume divisions 4 and entire or 6, that is the lateral ones 

 divided to the base, all awned; lemma 7-9 mm. long, tipped with a stout awn 

 3-4 mm. long. On high ridges in the Blue Mountains. 



Sitanion latifolium Piper. Similar to S. rigidum but larger; leaves broader; 

 glumes or their divisions 8 or sometimes 6, all awned. Perhaps not distinct 

 from 5. rigidum. High alpine ridges in the Blue Mountains. 



Sitanion hystrix (Nutt.) J. G. Smith. Stems 10-30 cm. high; sheaths and 

 blades pilose-canescent, the blades 1^1 mm. wide, flat or at length involute; 

 spike 5-7 cm. long, erect or nearly so; glumes or divisions 8, all awned; lemma 

 puberulent, 3-awned, the -recurved middle awn about 3 cm. long. In dry soil, 

 Spokane and Walla Walla. 



Sitanion velutinum Piper. Stems 30-40 cm. high; whole plant densely 

 puberulent with white soft hairs; blades flat; spikes 4-8 cm. long, erect; 

 glumes puberulent, entire, or rarely cleft or divided, all awned; lemma puberu- 

 lent, 3-awned, the awns 3-5.5 cm. long. Steptoe, C. R. Vasey. 



Family 16. CYPERACEAE. SEDGE FAMILY. 



Grass-like or rush-like herbs; stems slender, solid (rarely 

 hollow), triangular, quadrangular, terete or compressed; leaves 

 narrow with closed sheaths; flowers perfect or unisexual in spike- 

 lets, one (rarely two) in the axil of each scale (glume or bract} ; 



