478 



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



icle narrow, erect, closely flowered or 

 more or less interrupted at base, 10 to 

 25 cm. long; glumes equal or nearly 

 so, awn-pointed, 10 to 15 mm. long; 

 lemma 1 to 1.5 cm. long, including 

 the more or less twisted beak of about 

 3 to 5 mm. ; awns about equal, ascend- 

 ing, 1 to 2 cm. long. % — Dry 

 plains, stony hillsides, and open 

 forest, mostly at 1,500 to 2,500 m. 

 altitude, southern Colorado and west- 

 ern Texas to Arizona. 



Figtjee 701. — Aristida stricta, X 1. (Chase 4565, 



N. C.) 



30. Aristida stricta Michx. Pine- 

 land three- awn. (Fig. 701.) Peren- 

 nial; culms erect, 50 to 100 cm. tall; 

 blades closely involute, villous on the 

 upper surface above the base (the 

 hairs visible without unrolling the 

 blade), elongate, 1 mm. thick; pan- 

 icle slender, as much as 30 cm. long; 

 glumes about equal, 7 to 10 mm. 

 long; lemma 6 to 8 mm. long, scarcely 

 beaked; awns divergent, the central 

 1 to 1.5 cm. long, the lateral a little 



shorter. % — Common in pine bar- 

 rens, North Carolina to Florida, west 

 to Mississippi. 



31. Aristida rhizomophora Swallen. 

 (Fig. 702.) Perennial; culms tufted, 

 erect, 65 to 80 cm. tall, producing 

 well-developed scaly rhizomes; blades 

 firm, flat or folded, 7 to 10 cm. long, 

 1 to 2 mm. wide, those of the innova- 

 tions flexuous, as much as 30 cm. 

 long; panicle flexuous, 20 to 30 cm. 

 long, the distant branches somewhat 

 spreading, few-flowered, spikelet- 

 bearing from near the base; glumes 

 acuminate, usually awned, the first 8 

 to 14 mm. long, the second 12 to 17 

 mm. long (including the awn) ; lemma 

 9 to 12 mm. long, the callus 1 mm. 

 long, the awns flexuous, curved or 

 loosely twisted at base, spreading, the 

 central often reflexed by a semicir- 

 cular bend, 18 to 28 mm. long, the 

 lateral 15 to 20 mm. long. % — 

 Prairies, peninsular Florida. 



32. Aristida purpurascens Poir. 

 Arrowfeather. (Fig. 703.) Peren- 

 nial; culms tufted from a rather thin, 

 weak, sometimes decumbent base, 

 slender, 40 to 70 cm. or even 1 m. 

 tall; blades flat, rather lax and flex- 

 uous (especially the old ones), usu- 

 ally less than 2 mm. wide; panicle 

 narrow, rather lax and nodding, one- 

 third to half the entire length of the 

 plant; glumes about equal, mostly 8 

 to 12 mm. long; lemma about 7 mm. 

 long; awns about equal, divergent or 

 somewhat reflexed, 1.5 to 2.5 cm. 

 long. 91 — Dry sandy soil, Massa- 

 chusetts to Wisconsin and Kansas, 

 south to Florida and Texas; British 

 Honduras. 



33. Aristida parishii Hitchc. (Fig. 

 704.) Perennial; culms erect, 30 to 50 

 cm. tall; blades more or less involute, 

 sometimes flat, 1 to 2 mm. wide; 

 panicle narrow, 15 to 30 cm. long; 

 glumes short-awned, the first 12 mm. 

 long, the second 1 or 2 mm. longer; 

 lemma about 12 mm. long, tapering 

 into a short, straight or obscurely 

 twisted beak; awns about equal, di- 

 vergent, about 2.5 cm. long. % — 



