2d Andropogoneae 



Tribel. A.NDROPOGONEAE. Sorghum Tribe. 



Spikelets in spike-like racemes, 2 a1 each joint of the 

 rachis, 1 pedicellate and hermaphrodite, staminate or 

 rudimentary. Glumes usually 4, the first and second 

 empty. Large and mtich firmer in texture than the others, 

 the third usually empty or with a staminate flower in 

 its axil, rarely awned, the fourth or flowering glume 

 hyaline, usually awned, the awn generally twisted or 

 geniculate. 



Inflorescence composed of spike-like silky racemes. 1. Andropogon. 



Inflorescence paniculate ; spikelets somewhat silky-pubescent. 



2. Sorghum. 



1. ANDROPOGON L. 



Slender or rather coarse perennials with solid culms. 

 Spikelets heterogamous, in pairs at each joint of the 

 articulate and usually hairy rachis. one of each pair ses- 

 sile, hermaphrodite and 1-flowered, the other pedicellate 

 and staminate or rudimentary. Glumes of the fertile 

 spikelel 4, the first coriaceous, flattened on the hack with 

 a strong nerve near each margin and usually with 

 fainter ones between, second glume hyaline awned. 

 Stamens .".. Styles distinct ; stigmas plumose. Grain 

 imfurrowed, free within the hardened outer glumes. 



1 . A. glomeratua (Walt.) B. S. P. Culms erect, 4-6 dm. high, 

 Braootb, simple below, much branched above, upper nodes of 

 branches barbed; Bheaths compressed, glabrous or pubescent; 

 2-4 Him. wide, scabrous, long acuminate, nearly equaling 

 the ■■ulms, tlmse of the culms 15-4.") mm. long; branches elon- 

 gated, forming a compact terminal inflorescence; spikes in pairs. 

 aboul L'"> mm. long, loose, protruding from the sides of the 

 scabrous sheaths; rachis ilexuuus, the joints and pedicels pubes- 

 cent with long spreading silky hairs; outer glume ahout .'! mm. 

 nwn I'J-ls mm. long, scabrous; pedicelled spikelet reduced 

 to a single scale or wanting. I. macrourus Michx.J 



Bui i is. San Gabriel Mountains, KcClatchU. 



