GRAMINEAE (GRASS FAMILY) 



101 



, Leaves oblong-lanceolate to ovale-ianceolate, more than 5 mm 



Nodes bearded ; plants often pubescent, 

 liiades lanceolate, thick, glabrous above, densely Danillose- 



pubescent beneath . . * g5 



Blades ovate-lanceolate, thin ; pubescence when present 



soit ••.... 72 



Nodes not bearded ; plants glabrous or'neariy so' ' ' 

 Panicle spreading ; blades 2.5 cm. or more wide 73 



7 T31 A ^^^l^^^ narrow ; blades rarely over 1.8 cm. wide . * 66*. 

 I. Blades not over 1.5 cm. wide - uo . , 



67. 

 64. 



P. Wilcoxianum. 

 F. Leibergii. 



59. P. mutaUle. ' 

 70. P. aculeatum. 



65. P. Ravenelii. 



63. P. Scrihnerianum. 

 62. P. oligosanthes. 



P. clandestinum. 



P. Ravenelii. 

 P. Boscii. 



P. latifoliv/m. 

 P. n'anihojjhyaum, 

 ... Panicle narrow ; blades erect. 



pSl^^L'Sre-LX'"™ 66, /...a.a<,p.,,««. 



Spikelets not over 3 mm. long 



Spikelets4 mm. long . . * 



n. Panicle spreading, about as wide as long o. ' 

 o. bpikelets 3 mm. long; blades 1.2-2 dm long 

 Blades ciliate, glaucous, smooth , 



Blades not ciliate, green, scabrous 



O. Spikelets 3.5-4 mm. long ; blades not over 1dm. ionjr' 

 Nodes bearded ; ligule3-4 mm. long . 

 Nodes not bearded ; ligule 1-2 mm long ' * * * 

 Spike^lets obovoid-turgid, blunt; pubescence spread- 



Spikelets narrowly obovoid,' subacute ; pubescence 

 appressed .... 



j. Spikelets less than 3 mm. long p. 



p. Spikelets glabrous q. 



q. Spikelets not over 1,5 mm. long. 

 Plants pubescent . . . ' . 



Plants glabrous, except bearded node's 



g. Spikelets 2-2.5 mm. long r. • . . . 



r. Spikelets 2 mm. long. 



Spikelets obovoid-turgid; culms crlsp-puberulent 

 Spikelets elhptical; culms glabrous 



Autumnal state erect, branched like a little tree; second 



glume shorter than the fruit and sterile lemma 

 Autumnal state topheavy -reclining; fruit covered by 



second glume and sterile lemma 

 Autumnal state widely trailing ; second glu'me and ' 

 sterile lemma shorter than the fruit . . 

 r. Spikelets 2.5 mm. long. 



Culms 2^ dm. high; second glume and sterile lemma 



equaling fruit .... 

 Culms 5-12 dm. high; second glume 'and' sterile lemma 

 forming a point beyond the fruit 

 p. Spikelets pubescent s. 



USSE^lfiS™."^- • • ■ 2»- ^- ^erneH. 



Spikelets turgid, blunt; panicle-branches ascendin--- 



culms few m a tuft " ' 



Spikelets subacute; panicle-branches' spreading-: culms 

 numerous in a tuft . , *- & » 



s. Blades usually not conspicuously* elongate'd ; 'secondary 

 panicles not at the base t. ' y^^uuaiy 



t. Spikelets obovate-turgid, blunt, attenuate at base 

 bpikelets 2 mm. long .... 



Spikelets 2.5 mm. long. 



Spikelets not papillose ; culms glabrous 



Spikelets rugose-papillose ; culms pubescent, at least below' 



P. strigofium. 

 P. microcarpon. 



60. P. lancearium. 



27. 



28. 



P. dichotomum. 

 P. barbulatum. 



. 30. P. lucidum. 



26. P. BicknelUi. 

 29. P. yadkinense. 



IS. P. perlo?7(ju)77. 

 19. P. linear i/oli urn. 



25. P. aciculare. 

 6. P. BicknelUi. 



-Nodes bearded ; panicle-branches ascending 

 JO., ,^<^'^<^s not bearded; panicle-branches spreading '. 

 t. Spikelets not attenuate at base u. t s • 



u. Sheaths conspicuously retrorse-pilose ; culms simple, form- 

 ing soft tufts .... 



u. Sheaths not retrorselv pilose v. 



V. Sheaths, or all but the lowest, glabrous w 

 10. Ligule 2-5 mm. long. 



Spikelets 2.2 mm. h.ng .... 

 ^ pikelets 1.5 mm. long. 

 Panicle not more than half as wide as Ion? • 



spikelets elliptic \ 



Panicle about as wide as long ; spikelets obovoid* 



24. P. conxanguinen m 

 . P. angustifolium . 



21. P. xalapense. 



47. P. scoparioides. 



35. 

 36. 



P. spretum. 

 P. Lindheimeri. 



