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



19, Aristida patula Chapm. (Fig. 964.) Perennial, erect, as 

 muck as 1 m tall; blades flat, becoming involute especially at the 

 slender tip, elongate, 2 to 4 mm wide; panicle loose and open, one 

 third to half the entire length of the culm, the branches drooping, 

 naked below, as much as 20 cm long; glumes 12 to 15 mm long, 



nearly equal; lemma 10 to 12 mm long; 

 central awn straight, 2 to 2.5 cm long, 

 the lateral scarcely diverging, 5 to 10 

 mm long. % — Moist sandy pine bar- 

 rens and low open ground, peninsular 

 Florida. 



20. Aristida pansa Woot. and Standi. 

 Wooton three-awn. (Fig. 965.) Per- 

 ennial ; culms stiffly erect, slender, wiry, 

 20 to 40 cm tall; blades closely involute, 

 0.5 mm thick; panicle narrow, open, 

 rather stiffly upright, 10 to 20 cm long, 

 the branches stiffly ascending, 4 to 8 

 cm long; first glume 5 to 7 mm long, the 

 second 7 to 10 mm long; lemma about 

 as long as the second glume, tapering 

 into a scabrous slightly twisted beak 



Figure 959.-Aristidabarbata, XL (Wooton, ^^ ^ mm 1(mg . awng ^^ equftlj 



divergent or finally nearly horizontally 

 spreading, 10 to 20 mm long, the bases finally "somewhat curved or 

 warped. % — Plains and open ground, western Texas to Arizona. 

 21. Aristida spiciformis Ell. (Fig. 966.) Perennial; culms strictly 

 erect, 50 to 100 cm tall; blades 

 erect, flat or usually involute, 

 elongate, 1 to 3 mm wide; pan- 

 icle erect, dense and spikelike 

 10 to 15 cm long, more or les> 

 spirally twisted; glumes uns 

 equal, abruptly long-awned- 



Figure 961.— Distribution of 

 Aristida divaricata. 



the first 4 mm long, the second 

 8 to 10 mm long, the awns usu- 

 ally 10 to 12 mm long; lemma 

 5 to 6 mm long, extending into 

 a slender twisted column 1 to 

 3 cm long; awns about equal, 

 2 to 3 cm long, divergent or 



Figure 960.— Aristida jlwaricata, X 1. (Talbot, N.Mex.) 



horizontally spreading, more or less curved or warped at base % — 

 Pine barrens along the coast, South Carolina to Florida and Missis- 

 sippi; Cuba, Puerto Rico (fig. 967). 



