578 GRAMINEJS. (GRASS FAMILY.) 



* Bristles roughened downward. 



1. S. verticillata, Beauv. Culrns sparingly branched; leaves linear- 

 lanceolate, rough above ; spike cylindrical, compact, somewhat interrupted be- 

 low (2' -3' long) ; bristles short, single or by pairs. Around dwellings, North 

 Carolina, and northward. Introduced. Culm. 2 high. 



* * Bristles roughened upward. 



2. S. glauca, Beauv. Culms smooth, slightly compressed ; leaves linear- 

 lanceolate, rough above; spike nearly simple, cylindrical; bristles 6-10, in 2 

 clusters, longer than the spikelets ; perfect flower transversely wrinkled. Var. 

 L^EVIGATUM (Panicum laevigatum, Ell.} has a more flattened culm, longer, nar- 

 rower and smooth leaves, and the perfect flower obscurely wrinkled. Culti- 

 vated ground, the var. in damp soil along the coast, Florida to North Carolina. 

 Culms 1 -3 high. Spikes 2' -3' long, pale or purplish. 



3. S. viridis, Beauv. Culms smooth, terete ; leaves lanceolate or linear- 

 lanceolate, rough ; spikes compound, cylindrical, dense ; bristles 1 - 3 to each 

 spikelet ; perfect flower finely striate and dotted lengthwise. Around dwell- 

 ings. Introduced. June - Sept. Culms 1 - 2 high. Spikes 1' - 2' long. 



4. S. COrrugata, Schult. Culms, narrow (2" wide) leaves, and sheaths 

 rough; spikes compound, cylindrical, dense, erect or bending; spikelets 6-10 

 in a cluster; bristles one to each spikelet, elongated; perfect flower obtuse, 

 strongly wrinkled. (Panicum corrugatum, Ell.) Dry soil, Florida and Georgia. 

 July and Aug. Culms 2 - 3 high. Spikes 3' - 6' long, purple. 



5. S. composita, Kunth. Culms smooth; leaves linear-lanceolate, the 

 fringed sheaths rough-hairy at the throat; spikes loose, compound, the lower 

 clusters scattered ; bristles single or by pairs, many times longer than the spike- 

 lets ; perfect flower acute, with faint transverse lines. Dry sandy soil along 

 the west coast of Florida, Apalachicola to Key West. June -Aug. Culms 

 20-40 10^ Leaves 1 or more long. Spikes 6'- 12' long. 



6. S. Italica, Kunth. Culms tall (4 -8 high), smooth, branched; leaves 

 ('-!' wide) very rough; spikes compound (6' -18' long), cylindrical, dense, 

 the lower clusters scattered ; bristles 1 - 2 to each spikelet, elongated ; fertile 

 flower smooth and even. Swamps along the coast, Florida to North Carolina. 

 July -Sept. This, and Penicillaria spicata, Willd., are commonly cultivated, 

 under the name of MILLET, as green food for cattle. The latter seems to be 

 the Panicum cenchroides, Ell. 



51. CENCHRUS, L. COCK-SPUR. 



Prostrate or creeping grasses, with the spikelets of Panicum proper, but en- 

 closed, 1 - several together, in spiny or bristly, at length indurated and decid- 

 uous involucres ; the latter burr-like, and arranged in a terminal spike. Stamens 

 3. Styles united below. 



1. C. echinatus, L. Spikes cylindrical, composed of 20 or more globular 

 involucres (3' -4' long) ; involucre downy, spiny above, and with a row of rigid 

 barbed bristles above the base, 3 - 5-flowered ; culms ascending. Fields and 



