578 GRAMINEJE. (GRASS FAMILY.) 



5. P. conjugatum, Berg. Smooth and branching (2 long) ; leaves 

 thin, linear; spikes 2-3, Hat, the two terminal ones conjugate; spikelets 

 minute, in two rows, ovate, long-fringed. New Orleans (Dr. Hale), 

 Introduced. 



6. P. ciliatifolium, Michx. Culms 1- 2 high; leaves undulate, cili- 

 ate, smooth or hairy like the sheaths, 5'- 12' long, 6"- 10" wide ; spikes 2-4 

 in a terminal raceme, or solitary and axillary, closely flowered, 2' - 4' long ; 

 spikelets in pairs, roundish, \" -\\" long. Cultivated ground, common. 

 July -Sept. 



Var. dasyphyllum. Leaves and sheaths villous ; spikes mostly 3, the 

 axillary ones included; spikelets mostly single. (P. dasyphyllum, Ell.) 

 With the type. 



7. P. setaceum, Mirhx. Culms slender, l-2 high; leaves and 

 sheaths generally villous; spikes solitary, loug-peduucled, the axillary ones 

 short-peduncled or included ; spikelets single, " long. Dry sandy soil. 

 July - Sept. 



8. P. debile, Michx.? Mostly glabrous; culms filiform, 2 -3 high; 

 leaves 3' -6' long, 3" -5" wide; spikes mostly solitary, filiform, all on long 

 (6'- 10') setaceous peduncles, these often 2 or more from each sheath ; spike- 

 lets in pairs, ^" long. (P. longepeduuculatum, Leconte ?) Dry sandy soil 

 along the coast, Georgia and Florida. 



9. P. monostachyum, Vasey. Glabrous; culms strictly erect, 2 -3 

 high, simple; leaves narrow, erect, rigid, convolute, the lower 1-1^ long; 

 spike solitary, erect, long-peduucled, 6' -8' long; spikelets imbricated m two 

 rows, oblong-oval, 1-J" long. South Florida, and westward. 



* * Spikes 3-12 (rarely 2 or numerous), in a terminal raceme. 

 *- Rachis of the spike filiform : spikelets distinctly pedicelled. 



10. P. racemulosum, Nutt. Spikes 2-3, slender, erect (4' long); 

 spikelets single or by pairs, obovate, distant on the filiform and somewhat 

 flexuous rachis, distinctly pedicelled ; glumes smooth, obtuse, 7-nerved ; culms 

 simple, erect (2 -3 high); leaves long, linear, keeled, glaucous, sprinkled 

 with long white hairs. Dry sandy soil, Florida to North Carolina, and west- 

 ward. August -Sept. ^. 



- <- Rachis of the spike flat or trianynlar: spikelets sJtort-pedicelled. 

 = Spikelets a line, or less, long. 



11. P. purpurascens, Ell. Annual, nearly glabrous; culms erector 

 ascending, branching, l-3 long; leaves thin, broadly linear, 6' -12' long, 

 the sheaths often purple; spikes 2-12 (fewer on the branches), 2'-3' long; 

 spikelets 1" long, oval or roundish, crowded in 3 -4 rows under the broad 

 rachis ; glumes 5-nerved. Low ground in the middle and lower districts. 



12. P. plicatulum, Michx. Perennial, glabrous; culms simple, slen- 

 der, 2-3 high; leaves long, linear; spikes 3-5, distant, 2' long; spikelets 

 oval, in 3 rows under the narrow rachis, 1" long; second glume plicate within 

 the pale thickened margins. Georgia, Florida, and westward. 



13. P. csespitosum, Flugge. Culms slender, 1-H high; leaves 

 narrow-linear, ciliate; spikes 3-4, filiform, 1'long; spikelets in three rows, 



