MANUAL OF THE GRASSES OF THE UNITED STATES 



60 to 100 cm. tall; panicle 10 to 20 

 cm. long; lemma about 7 mm. long; 

 awn usually 3 to 5 cm. long. % — 

 Dry hills and plains, Montana to 

 Washington, south to Colorado and 

 California. 



459 



Figuhe 666.' — Stipa lettermani. Floret, 

 X 1; lemma, X 5. (Letterman 102, 

 Idaho.) 



Figupe 667. — Stipa williamsii. Floret, 

 X 1; lemma, X 5. (Williams 2804, 

 Wyo.) 



31. Stipa diegoensis Swallen. (Fig. 

 668.) Culms 70 to 100 cm. tall, sca- 

 berulous, densely pubescent below the 

 nodes; sheaths glabrous or scaberu- 

 lous; ligule 1 to 2 mm. long, obtuse 

 or truncate; blades 15 to 40 cm. 

 long, 2 to 4 mm. wide, flat or involute, 

 scabrous below, pubescent above; 

 panicle 15 to 30 cm. long, dense, the 

 branches appressed; glumes acumi- 

 nate, the first 9 to 10 mm. long, 1- 

 nerved, the second 8 to 9 mm. long, 

 3-nerved; lemma 6.5 to 7.5 mm. long, 

 the hairs at the summit 1 to 2 mm. 

 long, the callus 0.5 mm. long, sharp- 

 pointed; awn 2 to 3.3 cm. long, twice- 

 geniculate, scabrous. % — Along 

 streams in chaparral. Known only 

 from San Diego County (Jamul), 

 Calif., and northern Baja California. 



32. Stipa pinetorum Jones. (Fig. 

 669.) Culms in large tufts, 30 to 50 



Figure 668. — Stipa diegoensis. Floret, X 1; lemma 

 X 5. (Type.) 



cm. tall; ligule very short; leaves 

 mostly basal, the blades 5 to 12 cm. 

 long, involute-filiform, more or less 

 flexuous, slightly scabrous; panicle 

 narrow, 8 to 10 cm. long; glumes 

 about 9 mm. long; lemma 5 mm. 

 long, narrowly fusiform, clothed es- 

 pecially on the upper half with hairs 

 2 mm. long, forming a conspicuous 

 tuft exceeding the body of the lem- 

 ma, and bearing 2 hyaline teeth 1 

 mm. long at the summit; awn about 

 2 cm. long, twice-geniculate, nearly 

 glabrous. % — Open pine woods 

 at high altitudes, rare, Colorado to 

 Montana, Idaho, and California. 



Figure 669. — Stipa pinetorum. 

 Floret, X 1; lemma, X 5. (Jones 

 6023, Colo.) 



33. Stipa arida Jones. (Fig. 670.) 

 Culms 40 to 80 cm. tall; blades 10 to 

 20 cm. long, 1 to 2 mm. wide, flat or 

 involute, scabrous; panicle 10 to 15 

 cm. long, narrow, compact, pale or 

 silvery; glumes 8 to 12 mm. long; 

 lemma 4 to 5 mm. long; appressed- 

 pubescent on the lower half and along 

 the margin, slightly roughened toward 

 the summit; awn 4 to 6 cm. long, 



