12(8). Fruits (fertile lemmas) brown or brownish-olive at maturity (13) 



12. Fruits (fertile lemmas) whitish or stramineous at maturity (14) 



13(12). Panicle axis 12-25 cm. long; racemes 7 to 25 per panicle; spikelets con- 

 spicuously pubescent; fruits pale-brown 4. P. virgatum. 



13. Panicle axis to 13 cm. long; racemes 1 to 15 per panicle; spikelets essentially 



glabrous or minutely pubescent; fruits quite brown. .3. P. Bosciamim. 



14(12). Spikelets orbicular or suborbicular, glabrous 8. P. praecox. 



14. Spikelets longer than broad (15) 



15(14). Spikelets thickly turgidly plano-convex, usually pubescent: rachis rarely 



with purplish coloration; racemes only 1 to 6 per panicle 



1 1. P. pubiflorum. 



15. Spikelets flatly compressed plano-convex; rachis usually with a distinct pur- 



plish color; racemes usually more numerous, 3 to 15 per panicle 

 (16) 



16(15). Spikelets (2.1-) 2.3-2.7 (-2.9) mm. long, glabrous 9. P. lividum. 



16. Spikelets (2.2-) 2.5-2.9 (-3.2) mm. long, pubescent 10. P. Hartwegianum. 



1. Paspalum bifidum (Bert.) Nash. Fig. 142. 



Perennial from rhizomes 3-4 mm. thick with pubescent scales; aerial culms 

 5-12 dm. long, 2-3 mm. thick, erect, unbranched; ligule a thin brownish scale 

 1-5 mm. long; blades 1-5 dm. long, 3-14 mm broad, flat or folded, densely 

 pilose at least near the ligule and often on both surfaces; sheaths pilose; panicle 

 axis 12-20 cm. long; racemes 2 to 6, 4-16 cm. long, ascending or somewhat 

 spreading; rachis 0.5-0.8 mm. broad, triangular in transection, often markedly 

 zigzag; spikelets paired or by abortion a few solitary in the same raceme (the pairs 

 remote from each other and not much if at all overlapping), 3.6-4.2 mm. long, 

 ovate to obovate, brownish, turgidly plano-convex, glabrous; first glume present 

 as a minute triangle at the base of the sterile lemma; second glume and sterile 

 lemma firm-membranous; fruit brownish-green or olivaceous. Incl. var. projectum 

 Fern. 



In moist acid sand near bogs and open woods, in mud and shallow water of 

 bayous, sloughs, streams and ponds, in Okla. {Waterfall), infrequent or rare in 

 e. Tex., Sept.-Oct.; Coastai States, from Va. to Tex. and inland to Ark. and Okla. 



2. Paspalum floridanum Michx. Fig. 142. 



Robust perennial from short rhizomes 3-6 mm. thick with pubescent scales; 

 aerial culms (5-) 8-15 (-20) dm. long, 2-5 mm. thick, erect, unbranched; ligule 

 a brownish scale 1-2 mm. long; blades 1-5 dm. long, 4-13 mm. broad, firm, flat 

 or folded, glabrous to pilose; sheaths keeled, glabrous to pilose; panicle axis (when 

 racemes not solitary) 4-13 (-20) cm. long; racemes (1 or) 2 to 4 (to 6), 4-15 cm. 

 long, ascending or somewhat spreading; rachis 1-1.5 mm. broad, usually strongly 

 zigzag, the central rib to which the pedicels are attached even more markedly 

 zigzag, the very narrow margins thus interrupted; spikelets paired or by abortion 

 some solitary on the same raceme, 3.6-5 mm. long, ovate to obovate, usually 

 broadly so, brownish, turgidly plano-convex, glabrous; first glume always absent 

 or present as a mere minute line at the base of the sterile lemma; second glume 

 and sterile lemma firm-membranous, sometimes the latter slightly wrinkled; fruit 

 pale-brownish. Incl. var. glabratum Engelm. 



Permanently or seasonally moist clay or sandy loam, seepage areas, flatwoods, 

 in and about lakes and marshes, in shallow water in depressions in savannahs, and 

 in cat-tail ponds, in Okla. (Pittsburg. Ottawa, Love, Osage, Le Flore and Mayes 

 COS.) and e., s.e. and n.-cen. Tex. and extreme n.e. Rio Grande Plains, frequent, 

 summer-fall; N. J. to 111., Mo. and Kan., s. to the Gulf States. 



290 



