448 



MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



Figure 639. — Stipa speciosa. Panicle, X }4; floret, 

 X 5. (Reed 4853, Calif.) 



pubescent; blades 10 to 30 cm. long, 

 flat, often becoming involute, his- 

 pidulous beneath, 2 to 4 mm. wide; 

 panicle narrow, mostly not more 

 than 10 cm. long; glumes 12 to 18 

 mm. long; lemma about 1 cm. long, 

 the slender callus about 4 mm. long, 

 the body oblong, brownish, ap- 

 pressed-pubescent on the lower part, 

 papillose-roughened at least toward 

 the summit, abruptly narrowed into 

 a cylindric smooth neck about 1 mm. 

 long, the crown ciliate with short stiff 

 hairs; awn 6 to 10 cm. long, rather 

 stout, twice-geniculate, the first seg- 

 ment hispidulous, twisted, 2 to 3.5 

 cm. long. % — Dry, open grass- 

 land, Oklahoma and Texas to central 

 Mexico. Cleistogamous spikelets with 

 glumes obsolete and lemma nearly 

 awnless are borne in basal sheaths 

 just after maturity of panicle. 



2. Stipa speciosa Trin. and Rupr. 

 Desert needlegrass. (Fig. 639. 

 Culms numerous, 30 to 60 cm. tall; 

 sheaths brownish, smooth or the 

 lower pubescent or even felty at the 

 very base, the throat densely short- 

 villous; ligule short; blades elongate, 

 involute-filiform, mostly basal, more 

 or less deciduous from the outer and 

 older persistent sheaths; panicle nar- 

 row, dense, 10 to 15 cm. long, not 

 much exceeding the leaves, white or 

 taAvny, feathery from the plumose 

 awns; glumes smooth, 14 to 16 mm. 

 long, 3-nerved, long-acuminate, pa- 

 pery; lemma 7 to 9 mm. long, narrow, 

 densely short-pubescent, the callus 

 sharp and smooth below; awn with 

 one sharp bend, the first section 1.5 

 to 2 cm. long, densely long-pilose on 

 the lower two- thirds or more, the hairs 

 5 to 8 mm. long, the remaining por- 

 tion of the awn scabrous, the second 

 segment about 2.5 cm. long. % — 

 Deserts, canyons, and rocky hills, 

 Colorado and Arizona to southern 

 California; southern South America. 



3. Stipa leucotricha Trin. and 

 Rupr. Texas needlegrass. (Fig. 

 640.) Culms 30 to 60 cm. tall, the nodes 







Figure 640. — Stipa leu- 

 cotricha. Floret, X 1; 

 lemma, X 5. (Hitch- 

 cock 5138, Tex.) 



Figure 641. — Stipa 

 stillmanii. Floret, X 

 1; lemma, X 5. (Bol- 

 ander, Calif.) 



4. Stipa stillmanii Boland. (Fig. 

 641.) Culms stout, 60 to 100 cm. 

 tall; sheaths smooth, puberulent at 

 the throat and collar; ligule very 

 short; blades elongate, scattered, 

 folded or involute, firm, the upper- 

 most filiform; panicle 10 to 20 cm. 

 long, narrow 7 , dense or interrupted at 



