238 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 
Freely branching, creeping, shade-loving annuals or perennials, 
with erect flowering shoots, flat, thin lanceolate or ovate blades, and 
several one-sided, thickish, short spikes rather distant on a main axis. 
Species about 10, in the Tropics of both hemispheres, 1 extending 
into the Southern States. 
Type species: Oplismenus africanus Beauv. _ 
Oplismenus Beauv., Fl. Owar. 2: 14, pl. 58, f. 1. 1809. A single species is 
described. 
Orthopogon R. Br., Prodr. Nov. Holl. 194. 1810. Four species are described, 
O. compositus, O. aemulus, O. flaccidus, and O. imbecillis. Panicum compositum 
L. is chosen as the type, this being the basis of the first species of Orthopogon. 
The only species in the United States is Oplismenus setarius 
(Lam.) Roem. and Schult. (fig. 145), found in shady places from 
Florida to Texas. This is grazed by stock, but is not sufficiently 
abundant to be of importance. 
122. ECHINOCHLOA Beauv. 
Spikelets plano-convex, often stiffly hispid, subsessile, solitary or 
in irregular clusters on one side of the panicle branches; first glume 
about half the length of the spikelet, pointed; second glume and sterile 
lemma equal, pointed, mucronate, or the glume short-awned and the 
lemma long-awned, sometimes conspicuously so, inclosing a mem- . 
branaceous palea and sometimes a staminate flower; fertile lemma 
plano-convex, smooth and shining, acuminate-pointed, the margins 
inrolled below, fiat above, the apex of the palea not inclosed. 
Coarse, often succulent, annual, or sometimes perennial, grasses, 
with compressed sheaths, linear flat blades, and rather compact pani- 
cles composed of short, densely flowered racemes along a main axis. 
Species about 10, in the warm and temperate regions of both hemi- 
spheres; 4 species in the United States. 
Type species: Panicum crusgalli L. 
Echinochloa Beauv., Ess. Agrost. 58, pl. 11, f. 2. 1812. The species figured is 
selected as the type. 
With the exception of Echinochloa colonum (L.) Link, the species 
of Echinochloa have distinctly awned or awn-pointed spikelets. In 
that cosmopolitan species the spikelets are merely apiculate or mucro- 
nate, and the racemes are simple and rather remote. 
Echinochloa crusgalli (L.) Beauv. (fig. 146), barnyard grass, is 
a common weedy annual found throughout the country except at 
higher altitudes. The panicles vary much in the size and length of 
the awns, and in color vary from green to dark purple. In fields and 
waste places the plants are usually spreading, but in water or wet 
places may be stout and erect. An erect short-awned form, with 
short, ascending racemes, found in the Southwestern States, is the 
Mexican /. crusgalli zelayensis (H. B. K.) Hitche. (Oplismenus 
zelayensis H. B. K.). EF. crusgalli edulis (Panicum frumentaceum 
Roxb., 1820, not Salisb., 1796) is a form that has been cultivated in 
