Part 3, 1915] POACEAB 



217 



spreading or even reflexed, the short branchlets appressed, bearing short-pediceled, often rather 

 crowded spikelets, the axes angled and scabrous; spikelets narrowly oblong- ovate, 2-3.2 mm., 

 usually about 2.5 mm. long, about 0.9 mm. wide, acute, often greenish-purple; first glume one 

 fifth to one fourth the length of the spikelet, truncate or broadly triangular ; second glume and 

 sterile lemma more or less pointed beyond the fruit, rather faintly 7-nerved, the palea of the 

 sterile floret present or wanting; fruit 1.8-2 mm. long, about 0.8 mm. wide, elliptic. 



Type locality : Eastern United States. 



Distribution: Maine to Florida, Nebraska, and New Mexico; California; Panama; Bermu- 

 da, Bahamas, and the West Indies. 



Illustrations : Vasey, Agr. Grasses U. S. pi. 8; ed. 2. pi. 11 ; Bull. Tenn. Exp. Sta. 7: pi. 9,f. 36; 

 Bull. U. S. Dep. Agr. Agrost. 7: /. 51; Britt. & Brown, 111. Fl. /. 273 (aU as P. proliferum); ed. 2. 

 /. 314; Contr. U. S. Nat. Herb. 15: /. 31. 



This species has been erroneously referred to Panicum proliferum Lam., of the Old World, 



18. Panicum bartowense Scribn. & Merr. Circ. U. S. Dep. Agr. 



Agrost. 35: 3. 1901. 



Plants simple or sparingly branching, as much as 2 meters high, erect; culms glabrous, the 

 larger as much as 7 mm. thick; leaf -sheaths mostly longer than the internodes, papillose-hispid 

 or papillose only ; ligule 2-3 mm. long, the cilia more or less segregated in tufts; blades 15-40 cm. 

 long, 5-13 mm.wide, glabrous or more or less pilose above, rarely sparsely hispid beneath, rather 

 prominently papillose on the margin near the round but scarcely cordate base ; panicles large 

 and finally loosely spreading, 15-60 cm. long, the branches at first ascending, finally spreading, 

 the short branchlets and short-pediceled spikelets appressed as in P. dichotomiflorum; spikelets 

 2.2-2.7 mm. long, the glumes and fruit as in P. dichotomiflorum. 



Type locality: Bartow, Florida. 



Distribution: Florida, Bahamas, Cuba, and Jamaica. 



Illustration: Contr. U. S. Nat. Herb. 15: /. 33. 



,19. Panicum aquaticum Poir. in Lam. Encyc. SuppL 4: 281. 1816. 



Panicum chloroticum sylvestre Nees; Trin. Gram. Pan. 236. 1826. 

 Panicum hygrophilum Salzm.; Steud. Syn. Gram. 71. 1854. 

 Panicum proliferum strictum Griseb. Cat. PL Cub. 232. 1866. 



Plants perennial, mostly aquatic, glabrous except as noted; culms usually decumbent at 

 base, rooting at the nodes, erect branches often arising therefrom, the flowering culms erect, 

 simple or sparingly branching, averaging lower and more slender than in P. dichotomiflorum; 

 leaf -sheaths usually overlapping, rarely pilose at the juncture with the blade; ligule a ring of 

 hairs about 1 mm. long; blades commonly elongate, as much as 25 cm. long, but sometimes 

 5-10 cm. long and abruptly pointed, 5-10 mm. wide, linear, acute, occasionally sparsely pilose 

 on the upper surface toward the base; panicles terminal and axillary, short-exserted or included 

 at base, averaging smaller than those of P. dichotomiflorum, rarely as much as 20 cm. long, 

 less freely branching and fewer-flowered, the branchlets and pedicels smooth or nearly so on the 

 angles; spikelets 3-3.4 mm. long, 1 mm. wide, more gradually pointed than those of P. dichoto- 

 miflorum, the fruit slightly larger and more pointed than in that species. 



Typb locality: Porto Rico. 



Distribution: Cuba, Porto Rico, and Guadeloupe; Colima; Guatemala; also in tropical 



South America. 



Illustration: Contr. U. S. Nat. Herb. 17: /. 28. 



20. Panicum sucosum Hitchc. & Chase, Contr. U. S. Nat. Herb. 17: 



475. 1915. 



Plants perennial, glabrous throughout except as noted; culms few to several in a tuft, 

 1-1.5 meters long, decumbent at base and rooting at the lower nodes, succulent; leaf-sheaths 

 rather loose, about as long as the internodes; ligule a densely ciliate membrane about 1 mm. 

 long; blades flat or somewhat involute in drying, 15-30 cm. long, 5-9 mm. wide, linear, acu- 

 minate, scaberulous on both surfaces, sparsely pilose above toward the base; panicles 15-30 cm. 

 long, about half as wide, the axes and branches somewhat scabrous, the branches solitary or in 

 pairs, rather stiffly spreading, or finally horizontal, as much as 15 cm. long, naked at base for 

 1-2 cm., the internodes of the rachis mostly 3-5 cm. long, the branchlets appressed or as- 



