:. (GRASS FAMILY.) 579 



elliptical, \" long; glumes 3 nerved, minutely pubescent and granular. 

 (P. Blodgettii, Flora.) South Florida. 



14. P. Drummondi, Vasey. Culms 2-4 high, branching below; 

 leaves broadly linear, 6'- 10' long; spikes 3-4, 3' -4' long; spikelets in 2-3 

 rows, oval, 1" long, pubescent and granular. South Florida (Vasey), and 

 westward. 



15. P. virgatum, L. Culms 3 -5 high; leaves long, 3" -4" wide; 

 spikes numerous (20 or more), 2' -3' long, the lower mostly germinate; ra- 

 chis slender; spikelets \" long, in 4 rows, ovate; glumes acute, hairy along 

 the margin. Mississippi, and westward. 



= = Spikelets exceeding a line in length. 



16. P. prsecox, Walt. Very smooth and somewhat glaucous, or the 

 lower leaves and sheaths hairy; culms simple, slender, 2 -4 high; leaves 

 long and narrow ; spikes 3-6, 1' 3' long, bearded at the base; spikelets in 

 2-3 rows, orbicular, flat ; glumes 3-nerved. Low pine barrens. May - Oct. 



17. P. laeve, Michx. Mostly glabrous; culms simple, 2 -3 high; 

 leaves flat, 2" -3" wide, of varying length; spikes 2-5, slender, 2'- 4' long, 

 bearded in the axils ; spikelets in 2 rows, orbicular, \\" long ; glumes 5-nerved. 

 Moist ground, common. 



18. P. diflbrme, Leconte. Culms 2 -3 high, from creeping root- 

 stocks; leaves broadly linear ; spikes 2 -4, 2' -3' long; spikelets in 2 -3 rows, 

 oblong-oval, 1 \" long, glabrous. Low ground near the coast, North Carolina, 

 and westward. 



19. P. Floridanum, Michx. Culm stout, erect, 2 -4 high; leaves 

 rigid, broadly linear, l-2 long, smooth and glaucous, or the lowest densely 

 villous ; spikes 3-5, 2' -4' long; spikelets in 2-3 rows, oval or roundish, 

 about 2" long ; glumes glabrous. Damp or dry soil in the lower districts. 



20. P. dilatatum, Poir. Culms stout (3 -4 high) ; leaves flat, linear- 

 lanceolate, smooth ; spikes 4-6, racemose ; spikelets in .4 rows, ovate, acute, 

 villous on the margins, much wider than the flat rachis ; glumes 5-uerved, 

 longer than the roundish floret. Alabama, New Orleans, and westward. 

 Introduced. 



21. P. pubiflorum, Rupr., var. glabrum, Vasey. Culms stout, erect 

 from a creeping base, 2 -3 high ; leaves spreading, 6' -9' long, 4" -6" wide, 

 flat ; spikes 3 - 6, thick, spreading, 2' - 3' long ; rachis broad and flat ; spike- 

 lets in 3-4 rows, barely more than 1" long, oblong, obtuse, smooth or pubes- 

 cent. Tennessee, and westward. 



22. P. giganteum, Baldw. Culms very stout, 4 -6 high; leaves 1- 

 2 long, 1' wide, papillose-ciliate on the margins; spikes 3-4, 5' - 8' long, dis- 

 tant, spreading ; spikelets in 2 - 3 rows, about 2" long, oval, acute. East 

 Florida. Rare. 



-i- 4- -t- Rachis of the spikes broad, membranous, concave, covering the minute 

 spikelets: culms branching, creeping, or floating : spikelets in 2 rows. 



23. P. fluitans, Kunth. Culms mostly floating; leaves lanceolate, 4' -6' 

 long ; spikes numerous ; spikelets pubescent, concealed under the rachis. 

 Along rivers in still water. 



