2. Setaria glauca (L.) Beauv. Yellow Foxtail. Fig. 169. 



Loosely-tufted annual; culms 2-10 dm. long, often geniculate and decumbent 

 basally, ascending distally; blades 4-10 mm. broad, ascending; panicles 1-8 cm. 

 long, cylindric, about 1 cm. thick, fairly dense, a 1-cm. transection near the 

 middle including 11 to 20 spikelets; each spikelet subtended by numerous bristles, 

 mostly 2.5-3.2 mm. long, 1.4-2.1 mm. broad, rotundly ovate, turgid; lower (sterile) 

 floret usually staminiferous with a well-developed palea. S. lutescens (Weig.) 

 F. T. Hubb. 



In wet soil on edge of ponds, lakes and streams, in wet meadows, ditches 

 and on gravel bars along streams, in Okla. (Waterfall), nearly throughout Tex. 

 but absent from Rio Grande Plains and Plains Country, rare in the Trans-Pecos, 

 in N. M. (Sierra Co.) and Ariz. (Apache, Coconino, Gila, Maricopa, Cochise, 

 Yavapai, Pima and Yuma cos.), summer-fall; nearly throughout the temp, and 

 trop. areas of the world, introd. from Eur. 



3. Setaria verticillata (L.) Beauv. Fig. 170. 



Plants annual; culms to 1 m. long, simple or more often much-branched at 

 base, geniculately spreading and rooting at nodes; leaf blades flat, thin, scabrous 

 and sparingly pilose, 5-10 mm. wide, 10-20 cm. long; panicle erect, not rigid, 

 slightly tapered, sometimes interrupted at base, 5-15 cm. long, 7-15 mm. thick, 

 bristles 1 below each spikelet, retrorsely scabrous and 1 to 3 times as long as the 

 spikelet; spikelet 2 mm. long; fruit finely rugose. 



Along ditch banks and in muddy or waste places, in Okla. (Muskogee Co.) and 

 Ariz. (Coconino, Mohave, Cochise and Pima cos.); Mass. to N.D., s. to Ala., Mo. 

 and Okla., w. to Ariz, and Calif., introd. from Eur. 



4. Setaria magna Griseb. 



Robust annual; culms 1-4 m. tall, 5-20 mm. thick basally, prop-rooting from 

 the lower nodes but erect and simple; panicles 25-60 cm. long, 2-3 cm. thick, 

 dense (the axis mostly hidden); spikelets very numerous, about 2 mm. long; fertile 

 lemma smooth, shiny. 



In marshes, wet places, moist ditches, bayous, etc., s.e. Tex., summer-fall; 

 Coastal States, N.J. to Tex.; W.I., Yuc, C. R. 



56. Cenchrus L. 



About 160 species in warmer parts of the world. Individuals of this genus 

 are exceedingly abundant, especially so in disturbed, sandy, non-forested areas 

 and at elevations below 4.000 feet. Several species have been introduced, including 

 Pearl Millet and Napier Grass. Some authors segregate the genus into two genera 

 on trivial technical grounds. The spiny burs cause pain and sometimes infection 

 when they penetrate the skin, and they are noxious to animals when mixed with 

 hay. 



1. Cenchrus myosuroides H.B.K. 



Perennial from hard knotty subrhizomatous bases; culms 6-20 dm. long, erect; 

 panicle (6-) 10-23 cm. long, 6-12 mm. thick, interrupted at the very base, other- 

 wise rather dense, a 1-cm. transection near the middle containing 7 to 10 burs; 

 internodes of axis about 1-1.5 mm. long; burs about 3 mm. thick basally, the 

 bristles numerous (about 35 to 60 per bur), united only basally in the short cup 

 which does not equal the spikelets, greatly unequal (outer ones shortest), spreading 

 (outer) or ascending (inner ones), the inner ones stiff, none plumose. 



In ditches and near creeks or springs, infrequent in the Tex. Rio Grande Plains, 

 rare in the Trans-Pecos, summer-fall; Col., Ecu., Bol., Chile, Parag., Arg. and 

 extreme s. Braz.; also W.I. n. to Fla. Keys; Mex.; Tex. 



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