578 GRAMINE^E. (GRASS FAMILY.) 



* Bristles roughened downward. 



1. S. verticillata, Bcauv. Culms 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. 

 LJEVIGATUM (Panicum lajvigatum, 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 

 spikclet ; 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 

 2° -4° long. Leaves 1° or more long. Spikes 6'- 12' long. 



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

 (j'-l' 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 Penieillaria spicata, Will d., 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 ritjid 

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



