138 PANICACE^. 



almost acute, 2 mm. long; first glume broad, obtuse, 3-nerved, 

 about 1 mm. long; second and third equal, with cross nerves, 7- and 

 5-nerved respectively; fertile floret oval or ovate, abruptly acute, 

 finely striate, 2 mm. long. 



Florida, Curtiss 3607, Blodgett, A. P. Garher, all in herb. 

 Gray. 



61. P. INDICUM L. Mant. 2.: 184 (1771). 



Culms slender, branching, erect or difliuse, 40-60 cm. high. 

 Sheaths smooth; ligule 1 mm. long; blades and panicles often 

 purplish, smooth or scab rid, the former flat, 15-20 cm. long, 2-4 

 mm. wide. Panicle strict, dense, spikelike, 5-15 cm. long, 3-5 mm. 

 diam. ; rays 1-5 mm. long. Spikelets cuneate-ovate, smooth, 2 mm. 

 long; first glume 3-5-nerved, 1.3 mm. long; second and floral 

 glume of lower floret equal, 7-9-nerved ; fertile floret smooth, shin- 

 ing, oval, almost acute at both ends, 1.4 mm, long. 



Mexico (Jalisco), PringU 2363. 



Near shallow pools, probably introduced from the Old World. 



62. P. dichotomum L. Sp. PI. 1:58 (1753). 



Perennial; culms smooth or softly hairy, slender, simple or later 

 in the season branching freely along the middle, 20-50 cm. high, 

 rarely 15-90 cm. high. Leaf-blades near the base, tufted, firm, 

 ovate-lanceolate, 0.5-3 cm. long, the others flat, lanceolate, usually 

 5-7 cm. long, 5-7 mm. wide, holding their width well to the base, 

 some not over 3 cm, long, others 12 cm. long; blades and sheaths 

 usually containing some soft hairs, sometimes smooth, and on short 

 plants sometimes rough. The terminal panicle exserted, spreading, 

 compound, ovoid or pyramidal, 3-9 cm. long, the lateral ones 

 smaller, partially or wholly included. Spikelets few (10) to many 

 (250), on slender pedicels, oblong-ovate, obtuse, downy, less often 

 smooth, 1.5-2 mm. long; first glume broad, 1-nerved, minute to 

 one-third the length of the spikelet; second empty glume and floral 

 glume of the neuter floret equal, usually 7-nerved, occasionally with 

 one or two or more nerves ; joalea small, hyaline, the fertile floret 

 smooth, oval as long as the second and third glumes. 



Most parts of North America. 



Plants of various forms and perhaps varieties or even species 



