POACEAE. 27 



inof.e. [Greek, armed, presumably referring to the awns.] About 4 species, 

 natives of warm regions. Type species: Oplismenus africanus Beauv. 



]. Oplismenus hirtellus (L.) E. & S. Syst. 2: 481. 1817. 



Panicum liirtellum L. Syst. Nat. ed. 10, 870. 1759. 

 Oplismenus setarius E. & S. Syst. 2: 481. 1817. 



Culms prostrate or nearly so, rooting at the nodes, very slender, 6 dm. 

 long or less. Leaves ovate to ovate-lanceolate, acuminate, 1-6 cm. long, 1 cm. 

 wide or less, their sheaths often pubescent; panicle 8 cm. long or less, its 

 filiform short branches erect or spreading; spikelets 3 mm. long, the awns up 

 to 8 mm. long. 



Cultivated ground, New Providence : Bermuda ; South Carolina to Florida and 

 Texas ; the West Indies and tropical continental America. WOOD-GRASS. 



15. CHAETOCHLOA Scribn. Bull. U. S. Dep. Agr. Agrost. 4: 38. 1897 



Mostly annual grasses with erect culms and flat leaves, the inflorescence in 

 spike-like clusters. Spikelets 1-flowered, or rarely with a second staminate 

 flower, the basal bristles single or in clusters below the articulation of the 

 rachilla, and therefore persistent. Scales of the spikelet 4, the three outer 

 membranous, the third often subtending a palet and rarely a staminate flower; 

 the inner or fourth scale chartaceous, subtending a palet of similar texture 

 and a perfect flower. Stamens 3. Styles distinct, elongated. Stigmas plu- 

 mose. Grain free, enclosed in the scales. [Greek, in reference to the bristles 

 of the inflorescence.] 'Species about 35, in temperate and tropical regions. 

 Type species: Setaria longiseta Beauv. 



Inflorescence with the spikelets racemosely arranged : bristles 5-16 at the base of 



each spikelet, involucrate. 1. C. geniculata. 



Inflorescence with the spikelets in clusters or on manifest 

 branches ; bristles 1-3 at the base of each spikelet, not in- 

 volucrate. 



Spikelets 2 mm. long; leaves pubescent. 2. C. setosa. 



Spikelets 3 mm. long ; leaves glabrous. 3. G. macrosperma. 



1. Chaetochloa geniculata (Lam.) Millsp. & Chase, Field. Mus. Bot. 3: 37. 

 1903. 



Panicum geniculatum Lam. Encycl. 4: 727. 1798. 



Panicum imber'be Poir. Encycl. Suppl. 4: 272. 1816. 



Chaetochloa imberbis Scribn. Bull. U. S. Dep. Agr. Agrost. 4: 39. 1897. 



v 



Perennial; culms 6-12 dm. long, ascending. Sheaths smooth and glabrous, 

 compressed and keeled; leaves 1-3.5 dm. long, 2-6 mm. wide, pale green or 

 glaucous, smooth or nearly so ; spike-like panicle long-exserted, rather slender, 

 2.5-7 cm. long, about 1.5 cm. thick ; spikelets usually single, about 2.5 mm. 

 long and 1.25 mm. wide, the first scale ovate, 3-nerved, about one-half as long 

 as the spikelet, the second scale acute, 3-nerved, the third scale 5-nerved; 

 bristles in two nearly equal clusters of 5 each, very slender, 6-10 mm. long. 



Waste places, sink-holes, and in the scrub. Abaco, Great Bahama, Berry Islands, 

 Andros, New Providence, Exuma Chain, Acklin's Island, Fortune Island, Caicos 

 Islands, Grand Turk, Inagua, and Anguilla Isles : Bermuda ; Massachusetts to 

 Kansas, Florida and Texas; West Indies; tropical continental America. Referred 

 by Hitchcock and by Coker to Setaria glauca Beauv. ; and by Mrs. Northrop to 

 Chaetochloa glauca. FOX-TAIL GRASS. 



