442 MISC. PUBLICATION 200, TJ. S. DEPT. OF AGRICULTURE 



2. Aristida tuberculosa Nutt. (Fig. 935.) Annual; culms branch- 

 ing, 30 to 60 cm or even 1 m tall; blades involute, 2 to 4 mm wide 

 when flat; panicle 10 to 20 cm tall, the branches stiffly ascending; 

 glumes about equal, gradually narrowed into an awn, about 2.5 cm 

 long, including the awn; lemma 11 to 13 mm long, glabrous, except 

 for the slightly scabrous summit, extending downward into a densely 

 pubescent callus 3 to 4 mm long; column of awns twisted, 10 to 15 

 mm long, the upper 2 or 3 mm twisted but not united, above this 

 forming a semicircular bend, the terminal straight part of the awns 

 usually deflexed, 3 to 4 cm long, o — Open sandy woods, Massa- 

 chusetts to Georgia and Mississippi near the coast; around the southern 



Figure 934.— Aristida desmantha, X 1. 

 (Reverchon 3428, Tex.) 



Figure 935.— Aristida tuberculosa, X 1. (V. H. Chase 322, 

 Ind.) 



end of Lake Michigan and in other localities in Wisconsin, Indiana, 

 Illinois, Iowa, and Minnesota (fig. 936). 



3. Aristida californica Thurb. (Fig. 937.) Perennial, tufted, 

 much branched at base; culms pubescent, 10 to 30 cm tall; blades 

 mostly involute and less than 5 cm long; pan- 

 icles numerous, mostly reduced to few-flowered 

 racemes; first glume about 8 mm long, the 

 second about 12 mm long; lemma 5 to 7 mm 

 long, glabrous below, scaberulous toward the 

 summit, the strongly pubescent callus 1.5 to 2 

 mm long; column 15 to 20 mm long, the awns 

 about equal, 2.5 to 3.5 cm long, spreading 

 horizontally, the bases arcuate and slightly 

 contorted. % — Dry sandy or gravelly soil, deserts of southern 

 California, southwestern Arizona, and northern Mexico. 



4. Aristida glabrata (Vasey) Hitchc. (Fig. 938.) Perennial ; culms 

 erect, branched, glabrous, 20 to 40 cm tall; blades mostly involute, 

 those of the culm 1 to 3 cm long; panicle narrow, 3 to 6 cm long; first 

 glume 5 to 6 mm, the second 10 to 12 mm long; lemma 5 to 7 mm long, 



Figure 936.— Distribution of 

 Aristida tuberculosa. 



