588 GRAMINE^:. (GRASS FAMILY.) 



4. S. imberbis, R. & S. Glabrous; culms l-3 high; leaves linear, 

 8'- 10' long; spikes linear-cylindrical, 2' - 5' long ; bristles 4-8, about twice 

 as long as the spikelet; floret faintly rugulose. Manatee, Florida (Simpson), 



and westward. 



<- >- Spikes compound. 



5. S. viridis, Beauv. Culms smooth, l-3 high; leaves lanceolate- 

 linear, scabrous; spikes cylindrical, compact, l'-2' long; bristles 1-3; floret 

 finely striate and dotted. Cultivated ground. Introduced. 



6. S. COrrugata, Schultes. Culms, leaves, and sheaths scabrous ; spikes 

 compact, cylindrical, 3'- G' long, purple; bristle long, single; floret strongly 

 rugose. Dry saudy soil, Georgia and Florida. 



7. S. COmpOSita, Kunth? Culms smooth, 2 -4 high; leaves smooth- 

 ish, linear-lanceolate, 1 long, the sheaths ciliate, bearded at the throat ; spikes 

 loosely compound, 6' -12' long; bristles long, single or in pairs; floret ob- 

 scurely rugulose. Dry sandy soil along the west coast of Florida. 



8. S. magna, Griseb. Culms smooth, 4 -8 high; leaves long, scabrous, 

 A'-l' wide; spikes cylindrical, compact, 6' -18' long; bristles 1-2; floret 

 smooth and even. Wet ground near the coast. 



9. CENCHRUS, L. SAND-SPUR. COCK-SPUR. 



Spikelets as inPanicum proper, but enclosed, 1-5 together, in a downy and 

 spiny or bristly, at length indurated and deciduous involucre, these bur-like, 

 and arranged in a terminal spike. Cbiefly annual grasses, with branching 

 culms. Spines of the involucre barbed. 



1. C. echinatus, L. Culms ascending, l-2 long; leaves broadly 

 linear, 4' -6' long; involucres numerous, globular, spiny above, and with a 

 row of bristles above the base, 3 - 5-flowered. Fields and waste ground, 

 rather rare. 



2. C. tribuloides, L. Culms ascending, |-1| high; leaves linear, 

 flat ; involucres few, globular, the numerous spines spreading and reflexed, 

 mostly 3-flowered. Fields and waste ground, too common. 



3. C. incertUS, M. A. Curtis. Culm strict, erect or ascending (2 -3 

 long); leaves linear, folded, the lower sheaths longer than the iuternodes; 

 spike cylindrical, many-flowered ; involucre naked and acute at base, the 10 or 

 11 stout spines ciliate ; spikelets geminate, smooth; sterile flower triandrous. 

 (C. strictus, Chap in.} Sandy coast, Florida to North Carolina. 



4. C. myosuroides, IIBK. Tall (4 -6 high); leaves long, rigid, con- 

 volute ; spikes cylindrical, densely many-flowered ; involucre small, 1 -flowered, 

 armed with 20, or more, slender spines or brist'es, as long as its strongly 

 nerved spikelet. (Pauicum cenchroides, Ell.) South Florida (Bloil>/<tt), 

 Georgia (Elliott). 



10. PENNISETUM, Rich. 



Characters of Cenchrus, bnt the involucre composed of distinct scabrous bris- 

 tles, of which the interior are plumose below, and deciduous with the spikelets. 



1. P. setosum, Rich. Perennial, 2 -4 high; leaves linear, glabrous ; 

 spikes cylindrical, 3' - 6' long ; spikelets single ; lowest glume minute or none. 

 Lastero Bay, South Florida (Garber). 



