326 Bulletin No. 205 [March, 



Chaetochloa viridis (L.) Scribii. 

 Green Foxtail. Bottle Grass (Fig. 103) 



Setaria viridis, Vasey '61, 071; Patterson '76, 52; Flagg '78, 284; Higley 

 and Eaddin '91, 140; Huett '97, 129; Gleason '07, 181. 



Culms branching at the base, erect or spreading, 1 to 3 feet tall ; 

 sheaths and blades smooth, the blades 3 to 10 inches long, 4 to 12 mm. 

 wide; panicles less than 1 cm. broad; spikelets about 2 mm. long, 

 bristles 1 to 3, green, upwardly barbed. 



Green foxtail is found in the same places as yellow foxtail, C. 



lutescens, and may be exterminated in the ^ame way. 



CHAMPAIGN CO. Urbana, Clinton, Aug., 1895; Champaign, Gilbs, Oct., 1898; 

 Urbana, Seymour, June, 1880; Urbana, Mosher, Oct., 1913. christian co. Tay- 

 lorville, De Matte, cook CO. Hyde Park, Chicago, A. Chase, July, 1901; Landers, 

 Chicago, Hill, July, 1895. kankakee CO. Waldron, Eill, July, 1873. mchenry 

 CO. Algonquin, Nason, Aug., 1878. macoupin CO. Carlinville, Rohertson, Aug., 

 1882. PEORIA (0. Peoria, McDonald; Peoria, Brcndel. stark CO. Wady Petra, 

 V. H. Chase, Aug., 1897. wabash co. Without locality, Schnech, May, 1896. 



12. CENCHRUS L. 



Because of the peculiar burs which inclose the spikelets, the plants 

 belonging to this genus Avill never be confused with any other species 

 of grass. These burs are borne in a spike and are armed with stout 

 spines which are retrorsely barbed and often inflict painful wounds. 

 They are easily detached from the culm when they are mature and 

 are carried around by animals. Each bur contains from 2 to 6 spike- 

 lets which always remain and germinate inside the bur. The sheaths 

 are rather loose and the blades are short and narrow. The ligule is a 

 ring of short hairs less than 1 mm. in length. The plants are found 

 in waste places, usually where there is sandy soil. The only species 

 in Illinois is an annual. 



Cenchrus carolinianus Walt. 

 Sandbur. Bur Grass. Hedgehog Grass (Figs. 105 and lOG) 



Cenchrus trihuloidcs, Lapham '57, 548, 597; Flagg '78, 284; Brendel '87, 64; 

 Higley and Eaddin '91, 140; Huett '97, 129; McDonald '00, 103. Cenchrus caro- 

 linianus, Gleason '10, 148; Gates '12, 354. 



Culms flattened, 8 to 30 inches long, branched at nearly all the 

 nodes, usually spreading on the ground, the branches ascending, and 

 forming large mats; sheaths loose, flattened, smooth; blades smooth, 

 sometimes folded, 2 to 5 inches long, 5 to 10 mm. broad; burs about 8 

 mm. thick, the surface pubescent between the spines. 



This species is a troublesome weed in some situations, but it may be 

 eradicated by thoro cultivation. 



ILLINOIS specimens: Without locality, Vasey. carroll co. Near Mississ- 

 ippi river, Pepoon, Aug., 1879. champaign CO. Champaign, Gibhs, Oct., 1898; 

 Champaign, Seymour, Sept., 1880. cook co. Chicago, Lansinrj ; Chicago, Bah- 

 coclc, July, 1874; Ravenswood, Reynolds, kankakee co. Altorf, Hill, July, 1873. 



