MANUAL OF THE GRASSES OF THE UNITED STATES 



pilose; blades 4 to 7 cm. long, 8 to 

 15 mm. wide, thin, ovate-lanceolate, 

 asymmetrical, ciliate at the base; 

 panicles 8 to 15 cm. long, the slen- 

 der ascending to spreading branches 

 with capillary, spreading, few-flow- 

 ered branchlets; spikelets about 1.3 

 mm. long, acute, sparsely pubes- 

 cent. O — Waste places, woods 

 and open ground, Texas (Browns- 

 ville); Mexico and the West Indies 

 to Peru and Brazil; southeastern 

 Asia and the Philippines. 



695 



Figure 1056. — Panicum plenum. Two views of spike- 

 let, and floret, X 10. (Type.) 



8. Maxima. — Tall robust perennials; 

 ligules membranaceous, ciliate; 

 blades linear, flat; panicles large, 

 many-flowered; spikelets ellip- 

 soid, faintly nerved, glabrous; 

 fruit transversely rugose. 



146. Panicum maximum Jacq. 

 Guinea grass. (Fig. 1055.) Plants 

 light green, in large bunches from 

 short stout rhizomes; culms mostly 

 erect, the nodes usually densely 

 hirsute; sheaths papillose-hirsute to 

 glabrous, usually densely pubescent 

 on the collar; ligule 4 to 6 mm. long; 

 blades 30 to 75 cm. long, as much as 

 3.5 cm. wide, glabrous, very scabrous 

 on the margins, sometimes hirsute on 

 the upper surface near the base; 

 panicles 20 to 50 cm. long, about 

 one-third as wide, the long rather 

 stiff branches ascending, naked at 

 base, the lower in whorls, the axils 

 pilose, the branchlets short, appressed, 

 bearing more or less clustered short- 

 pediceled spikelets; spikelets 3 to 3.3 

 mm. long; first glume about one- 

 third the length of the spikelet. % 

 — Fields and waste places, southern 

 Florida, and southern Texas, intro- 

 duced from Africa; tropical regions 

 of both hemispheres at low altitudes. 

 Guinea grass is the most important 

 cultivated forage grass of tropical 

 America. It grows in moderately dry 

 ground and can be used for pasture 

 or for soiling. Much of the green 

 feed cut for forage is this species. 



147. Panicum plenum Hitchc. and 

 Chase. (Fig. 1056.) Plants mostly in 

 large clumps, mostly glaucous from 



a stout rhizome; culms 1 to 2 m. 

 tall, erect from a usually decumbent 

 base, compressed; sheaths glabrous, 

 somewhat keeled; blades 20 to 35 

 cm. long, 7 to 17 mm. wide, glabrous 

 or nearly so; panicle 20 to 50 cm. 

 long, open; spikelets 3 to 3.4 mm. 

 long. 91 — Moist places in rocky 

 hills and canyons, Texas to Arizona; 

 Mexico. Differs from P. bulbosum in 

 the absence of the basal corm. 



Figure 1057. — Panicum bulbosum. Base of culm, X 

 ^2 ; two views of spikelet, and floret, X 10. (Lemmon 

 2914, Ariz.) 



148. Panicum bulbosum H. B. K. 



Bulb panicum. (Fig. 1057.) Culms 

 in tufts, 1 to 2 m. tall, erect, the 

 lowest internode thickened to a hard 

 cormlike base 1 to 2 cm. thick, bud- 

 ding at base, sometimes with one or 

 more corms of previous years at- 

 tached; sheaths glabrous or pilose 

 toward the summit; blades 25 to 60 

 cm. long, 3 to 12 mm. wide, sca- 

 brous above, glabrous beneath; pan- 

 icle 20 to 50 cm. long, open; spikelets 



