GRASSES OF IOWA. 



27 



Inflorescence paniculate. 



Pedice'led spikelet wanting (in one species) (Chrysopogori). . .A. nutans. b 

 Pedicelled spikelet present {Sorghum). 



Perennial from stout rootstocks A. Halepensis .* 



Annual, cultivated A. Sorghum." 



1. ANDROPOGON SCOPAR1US. 

 Andropogon scoparius. Michx. Fl. Bor. Am. 1: 87 1803. Watson 

 and Coulter. Gray. Man. Bot. 637. 1890. (6th ed). Scribner. Grasses of Tenn. 

 Bull. Uuiv. Tenn. Agrl. Exp. Sta. 7: 21. / 6. 1894. Bull. U. S. Dept. 

 Agrl. Div. Agros. 7: 19 /. 13 1900. (3 ed.) Beal. Grasses of N. A. 2: 46. 

 1896. Nash in Britton and Brown, 111. Fl. 1: 10 1. /. 216. 1896. 



DESCRIPTION. 



Little Blue Stem. A rather slender perennial, one to three feet 

 high, more or less paniculate-branched above, the single racemes terminal 

 on the culms or branches. Culms somewhat compressed below. Leaf 

 sheaths carinate, smooth, scabrous or often pilose; ligule about a line 

 long, truncate, leaf blade 

 blade 2 to io inches (4- 

 20cm.) long, 1 to 3 inches 

 (2-6 mm.) wide, very 

 acute, the mid-vein promi- 

 nent below. Spathe 1 to 2 

 inches (2-5011.) long, nar- 

 row and acute, or with 

 a short rudimentary blade, 

 apex of the peduncle 

 smooth or sparingly pilose. 

 Racemes partially enclosed 

 within the spathe, or more 

 often exserted, erect in 

 flowering, 6 to 12 jointed, 

 the rachis straight or 

 usually flexuose; joints 

 rather slender, some- 

 what thickened above, 

 rounded and scabrous on 

 the back, flattened on the 

 anterior face, pilose on the 

 edges from near the mid- 

 dle, the hairs increasing 

 in length towards the apex, 

 about one-half the length 



of the sessile spikelet. Ped- FlG . 20. Andropogon scoparius.-a, Spikelet: 6, c, 

 1, •! 1 . 1 , . first and second eh. mes: d. third glume; f, lodicules; 



icellate spikelet reduced to a ^rj. s. Dept. Agrl. Div. Agros.) 



