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



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

 much 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. 91 Moist sandy pine bar- 

 rens and low open ground, peninsular 

 Florida. 



20. Aristida pansa Woot. and Standl. 

 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 



divergent or finally nearly horizontally 

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

 warped. 9L 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 un s 

 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'divaricata, X 1. (Talbot, N.Mex.) 



horizontally spreading, more or less curved or warped at base. 91 ~ 

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

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



