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



otherwise glabrous or nearly so, the 

 blades 2 to 7 mm. wide, scabrous: 

 panicles from rather long-exserted to 

 included at base, those of the branch- 

 es often partly included in dilated 

 sheaths, silvery to creamy white, 

 silky, subflabellate, mostly 7 to 10 

 cm. long; racemes several to many, 

 or sometimes few on the branches, 

 2 to 6 cm. long, the common axis 

 usually shorter than the racemes, 

 rarely longer; rachis joints and ped- 

 icels copiously long-villous, the hairs 

 on the average longer than in A. 

 saccharoides; spikelets 5 to 6 mm. 

 long, the awn twisted below, genicu- 

 late, 20 to 25 mm. long; pedicellate 

 spikelet reduced. 01 — Mesas, 

 rocky slopes, and open ground, Okla- 

 homa and Texas to California and 

 Arizona, south through Mexico. Has 

 been confused with .4. saccharoides, 

 differing chiefly in the subflabellate 

 panicle and larger spikelets. 



34. Andropogon saccharoides 

 Swartz. Silver beardgrass. (Fig. 

 1173.) Culms tufted, 60 to 130 cm. 

 tall, erect or ascending, often branch- 

 ing below, the nodes from appressed 

 hispid to glabrous; foliage commonly 

 glaucous, glabrous or nearly so, the 

 blades 3 to 6 mm. wide; panicle long- 

 exserted or those of the branches 

 short-exserted, silvery white, silky, 

 dense, oblong, mostly 7 to 15 cm. 

 long; racemes 2 to 4 cm. long, the 

 common axis mostly at least twice 

 as long, but readily breaking; rachis 

 joints and pedicels long-villous; spike- 

 lets about 4 mm. long, the delicate 

 awn twisted below, geniculate, 10 to 

 15 mm. long; pedicellate spikelet re- 

 duced. 01 — Prairies and rocky 

 slopes, especially in limestone areas, 

 Missouri to Colorado, and Alabama 

 to Arizona; Mexico and West Indies 

 to Brazil. Our plants, which have 

 been differentiated as ,4. torreyanus 

 Steud., are more freely branching 

 than the typical form of the "West 

 Indies. 



35. Andropogon exaristatus (Xash) 

 Hitchc. (Fig. 1174.) Resembling A. 



iwe 1171 --^^X' l 8 ,T£:f us ' X L (Hitch " saccharoides; panicle slender, spike- 



Figuke 1170. — Andropogon wrightii, X 1. (Metcalfe 

 1371, N. Mex.) 



hills, and dry woods, southern Texas; 

 Mexico. 



33. Andropogon barbinodis Lag. 

 (Fig. 1172.) Culms tufted, 40 to 120 

 cm. tall, spreading to ascending, often 

 branching below, the nodes bearded 

 with short spreading hairs; sheaths 

 sparsely hairy in the throat, foliage 



