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2 lines long; outer glumes lanceolate, acute, five to seven- 
nerved, one-third longer than the flowering glume. 
Var. VILLOSUM; leaves and sheaths very villous. 
SECTION EUPASPALUM, BENTH. 
Spikelets more or less secund along the rhachis, with the back 
of the flowering glume turned zzwards or toward the rhachis. 
; Subsection CERESIA, Benth. i 
Rhachis of the spikes membranaceous, dilated and applied close 
to, and nearly enclosing the flowers when mature. 
3. P. fluitans, Kth.—Culms 1 to 3 feet long, from a creeping 
or floating rhizoma; leaves flat, broad linear ; spikes numerous 
(40 to 50), alternate and verticillate, divaricate, slender, 2 to 2% 
inches long; spikelets in two rows, % line long, oblong, pubescent. 
Subsection OPISTHION, Benth. 
Rhachis of the spikes flat, not dilated. 
(a) Spikes digitate, in terminal pairs, or rarely 3 or 4. 
4. P. conjugatum, Berg.—Spikes divaricate, 2 to 5 inches 
long; spikelets very numerous (25 to 30 to the inch), secund, ovate, 
rather acute, hardly a line long, sterile glumes ciliate on the margins. 
5. P. notatum, Flugge.—Culms rather stout; spikes thick, 
2 to 3'% inches long, erect-spreading; spikelets ovate, obtuse, 
1% lines long, smooth, five-nerved. 
6. BP. distichum, Linn.—Culms erect from a creeping 
rhizoma, 6 inches to 2 feet high; leaves lanceolate, acute, fat, 
2 to 3 lines wide; spikes little spreading, 1 to 2 inches long, not 
as thick as in P. xotatum ; spikelets oblong, acute or acutish, 
smooth, about 10 pairs to the inch. 
7. P. vaginatum, Swz.—Culms from stout, creeping root- 
stocks, in wet ground or water, very leafy; leaves distichous, 
involute and pointed; sheaths loose; spikes I to 3 inches long, 
erect or spreading; spikelets oblong-lanceolate, acute, smooth ; 
sterile glumes very ¢hin, three to five-nerved, the lower without 
midrib. This species is united with the preceding by Bentham. 
(4.) Spikes single and terminal, or one terminal and one (rarely 
more) additional, approximate, with sometimes axillary pedun- 
cled ones. 
8. P. monostachyum, Vasey in Chapm. Suppl. to Southern 
Flora.—Culm with spike 2 to 3 feet high, both rigidly erect ; 
