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MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



short; blades 7 to 13 cm. long, 6 to 12 

 mm. wide, the crowded lower ones 

 usually much larger than the others; 

 panicle 6 to 12 cm. long, rather nar- 

 row, densely flowered, spikelets 1 to 

 1.2 mm. long, nearly spherical, 

 densely puberulent. Autumnal culms 

 remaining erect, late in the season 

 producing branches from the third or 

 fourth node, the branches nearly as 

 long as the primary culms. 91 — 

 Moist pine barrens, swamps, and bor- 

 ders of ponds, North Carolina to 

 Florida and Louisiana; Cuba. 



11. Ensifolia. — Low and slender, 

 mostly glabrous throughout (ex- 

 cept in P. curtifolium and P. 

 tenue); ligules nearly obsolete; 

 spikelets 5- to 7-nerved. Autum- 

 nal culms simple to freely branch- 

 ing. 



Figure 985. — Panicum tenue. Two views of spikelet, 

 and floret, X 10. (Type.) 



76. Panicum tenue Muhl. (Fig. 



985.) Vernal phase olive green; culms 

 20 to 55 cm. tall, sometimes sparsely 

 appressed-pubescent below; sheaths 

 puberulent between the nerves or 

 sparsely appressed-pilose, or the up- 

 per glabrous; blades distant, 2 to 5 

 cm. long, 3 to 4 mm. wide, rather 

 thick, the margin cartilaginous, pu- 

 berulent beneath, glabrous on the up- 

 per surface; panicle 3 to 5 cm. long; 

 spikelets 1.6 to 1.7 mm. long, puber- 

 lent. Autumnal culms erect or lean- 

 ing, sparingly branching from the 

 middle nodes, the branches in small 

 fascicles. % — Moist sandy woods, 

 eastern North Carolina to northern 

 Florida. 



77. Panicum albomarginatum 

 Nash. (Fig. 986.) Vernal culms 15 to 

 40 cm. tall, ascending or spreading; 

 leaves crowded at the base; blades 

 thick and firm, those of the midculm 



4 to 6 cm. long, 4 to 6 mm. wide, with 

 a prominent white cartilaginous mar- 

 gin, the uppermost much reduced; 

 panicle 3 to 6 cm. long; spikelet 1.4 to 

 1.5 mm. long, puberulent. Autumnal 

 culms spreading, branching at the 

 base, forming bushy tufts. % 

 Low sandy soil, Coastal Plain, south- 

 eastern Virginia to Florida, Tennes- 

 see, Arkansas, and Louisiana; Cuba; 

 Guatemala. 



78. Panicum trifolium Nash. (Fig. 

 987.) Vernal phase similar to that of 

 P. albomarginatum, the culms more 

 slender, 20 to 50 cm. tall, the blades 

 less crowded at the base, the upper 

 blade not reduced. Autumnal culms 

 erect or leaning, sparingly branching 

 from the middle and upper nodes. 

 % — Low, mostly moist, sandy 

 woods, New Jersey to Florida and 

 Texas; Tennessee. 



^N 



M 



Figure 986. — Panicum albomarninatum. Two views of 

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



Figure 987. — Panicum trifolium. Two views of spike- 

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



79. Panicum flavovirens Nash. 

 (Fig. 988.) Vernal phase bright glossy 

 green; culms very slender, ascending 

 or spreading, 15 to 30 cm. tall; blades 

 2 to 5 cm. long, 3 to 4 mm. wide, 

 thin; panicle few-flowered; spikelets 

 1.3 to 1.4 mm. long, pubescent. Au- 

 tumnal culms spreading, decumbent 

 or prostrate, branching from the 

 lower and middle nodes. % 

 Moist, shady, or mucky soil, North 

 Carolina to Florida and Mississippi. 

 Panicum albomarginatum, P. trifol- 

 ium, and P. flavovirens form a series 

 of closely allied species. 



