84 GRASSES OF IOWA. 



KEY TO THE SPECIES OP SETARIA. 



Bristles downwardly barbed 5. verticillata . i 



Bristles upwardly barbed. 



Bristles 5-16 at base of each spikelet. Second empty glume much shorter 



than the flowering glume 5. glauca." 



Bristles 1-3 at base of each spikelet, second empty glume nearly or quite 

 equalling the flowering glume. 

 Spike-like panicle 2-8 cm. long, 1 cm. or less thick, spikelets 2 mm. 



long , bristles green 5. viridis . 3 



Spike-like panicle 5-20 cm. long, 1-3 cm. thick, spikelets 2.5 to 3 mm. 

 long , bristles usually purple , cultivated S. Italica . 4 



1. SETARIA VERTICILLATA. 



Setaria verticillata Beauv. Agrost. 51. 1812. Watson and Coulter in 

 Gray's Man. Bot. 634. Vasey. Contr. U. S. Nat. Herb. 3: 39. 



Panicum ver tici i 'latum L. Sp. PI. 82. 1762. (2. ed.) 



Chamaeraphis verticillata Porter. Bull. Torr. Bot. Club. 20: 196. 1893. 

 Beal. Grasses. N. A. 2: 151. 



Ixophorus verticil 'latus Nash. Bull. Torr. Bot. Club. 22: 422. /. 6. 1895. 

 Britton and Brown. 111. Fl. 1: 126./. 280. 1896. 



Pennisetum verticil latum R. Br. Prod. 1: 195. 1810. 



Chaetochloa verticillata (L.) Scribn. Bull. Div. Agros. U. S. Dept. 

 Agrl. 4: 39. Scribner & Merrill. Bull. U. S. Dept. Agrl. Div. Agr. 21: 16. 

 /. 6. 



DESCRIPTION. 



Whorled Millet. A low, spreading, much-branched annual, 

 \ to I foot (1-3 dm.) high, with short, cylindrical spikes and lanceolate 

 leaves, i| to 3 inches (3-6 cm.) long. Culms compressed, geniculate, 

 decumbent, very glabrous: nodes smooth; sheaths very loose, striate, 

 compressed, glabrous, margins smooth, shorter than the internodes; 

 ligule short, densely ciliate-fringed with white hairs; leaf blades 

 1 \ to 3 inches (3-6 cm.) long, 2 to 4 lines (4 to 8 mm.) wide, cordate 

 at the base, long-acuminate at the apex, scabrous, and sparingly papillate- 

 ciliate on both sides, especially below, margins cartilaginous, serrulate- 

 S< abrous. Inflorescence dense, cylindrical, 1-3 cm. in diameter, pur- 

 plish ; common axis angular, scabrous, branches very short, subverticil- 

 latc, densely flowered, setae 1-2, purple, stout, flexuous, retrorsely scab- 

 rous, 3-8 mm. long. Spikelets 1.5-2 mm. long, nearly sessile, elliptical- 

 ovate; first glume triangular ovate, acute or obtuse, 3-nerved, about one- 

 third the length of the spikelet; second glume ovate, obtuse, 5-7 nerved, 



