270 NORTH AMERICAN FLORA [Voujms 17 



164. Panicum tenue Muhl. Descr. Gram. 118. 1817. 



Panicum deustum Brickell & Enslen; Muhl. Descr. Gram. 1 19, as synonym. 1817. Not P. deustum 

 Thunb. 1794. 



Panicum liton Schultes, in R. & S. Syst. Veg. Mant. 2: 250. 1824. 



Panicum unciphyllum Trin. Gram. Pan. 242. 1826. 



Panicum macrum Kunth, Rev. Gram. 40. 1829. 



Panicum parvulum Muhl.; Scribn. & Merr. Circ. U. S. Dep. Agr. Agrost. 27: 4, as synonym. 1900. 



Not P. parvulum Trin. 1834. 



Vernal phase olive-green; culms in rather small tufts, 20-55 cm. high, slender, erect from 

 a more or less geniculate base, glabrous, or the lower intern odes sparsely appressed-pubescent, 

 the nodes glabrous, appressed-pubescent, or appressed-pilose ; leaf -sheaths usually much shorter 

 than the internodes, puberulent between the nerves to sparsely appressed-pilose, or the upper 

 glabrous; ligule 0.3-0.5 mm. long, dense; blades distant, ascending or spreading, 2-5 cm. long, 

 3-4 mm. wide, rather thick and with a cartilaginous, often white, margin, involute-pointed, 

 usually densely puberulent beneath, glabrous on the upper surface or puberulent toward the 

 base; panicles long-exserted, 3-5 cm. long, about as wide, pyramidal, open, rather few-flowered, 

 the flexuous branches spreading; spikelets 1.6-1.7 mm. long, elliptic, subobtuse, densely puberu- 

 lent ; first glume one fifth as long as the spikelet or less, obtuse ; second glume shorter than the 

 fruit and sterile lemma; fruit 1.4-1.5 mm. long, elliptic, subobtuse. 



Autumnal culms erect or leaning, sparingly branching from the middle nodes, the branches 

 in small fascicles, shorter than the primary internodes, the blades not much reduced; winter 

 rosette conspicuous, the thick, cartilaginous-margined, involute-pointed blades 3-5 cm. long, 

 4-7 mm. wide, persistent (but usually dead) during the succeeding year. 



Typ^ locality : Southeastern United States, the exact locality not known. 

 Distribution: North Carolina and Florida. 

 Illustration: Contr. U. S. Nat. Herb. 15: /. 281. 



165. Panicum albomarginatum Nash, Bull. Torrey Club 24: 40. 



1897. 



Vernal plants usually grayish-green, often purplish; culms densely tufted, 15-40 cm. high 

 (rarely taller), slender but firm, ascending or spreading, glabrous including the nodes; leaves 

 crowded at the base, distant above; sheaths sometimes pubescent on the margin and at 

 the summit, otherwise glabrous, or the lowermost sometimes obscurely pubescent; ligule 0.3 

 mm. long, dense; blades thick and firm, those of the midculm 4^6 cm. long, 4^6 mm. wide, 

 rounded at the base, with a prominent white, finely serrulate, cartilaginous margin, as- 

 cending or spreading, glabrous, the crowded basal blades as much as 1 1 cm. long, and the upper- 

 most blade usually much reduced ; panicles finally long-exserted, 3-6 cm. long, nearly as wide, 

 rather densely flowered, the flexuous branches ascending or spreading; spikelets 1.4—1.5 mm. 

 long, 0.7 mm. wide, obovate-elliptic, subobtuse,- turgid at maturity, densely puberulent; first 

 glume one fifth to one fourth as long as the spikelet, obtuse or subacute; second glume and sterile 

 lemma scarcely equaling the fruit at maturity; fruit 1.25 mm. long, 0.65 mm. wide, elliptic, 

 subacute. 



Autumnal phase spreading, the primary culms branching from the base and lower nodes, 

 these early branches much longer than the primary internodes and repeatedly branching, 

 forming bushy tufts, the ultimate branchlets and reduced blades appressed; winter blades 

 stiffly erect or spreading, very smooth and firm. 



Type locality: Eustis, Florida. 



Distribution: Virginia to Florida and Louisiana; Cuba; Guatemala. 



Illustrations: Bull. U. S. Dep. Agr. Agrost. 17: /. 359; Contr. U. S. Nat. Herb. 15: /. 283. 



166. Panicum trifolium Nash, Bull. Torrey Club 26: 580. 1899. 



Vernal phase similar to that of P. albomarginatum, but the culms in smaller tufts, taller, 

 20-50 cm. high, more slender, erect; leaves less conspicuously crowded at the base, not so stiff, 

 and proportionately not so much longer than those of the mid-culm; sheaths much shorter 

 than the elongate internodes; blades 3-5 cm. long, 4-5 mm. wide, rather less thick and firm 

 than those of P. albomarginatum, the uppermost blade not reduced; panicles usually short- 

 exserted, 3-5 cm. long, about as wide, loosely flowered; spikelets as in P. albomarginatum but 

 hardly as wide or as turgid, and the fruit rather less exposed at maturity. 



