J 02 



GR AMINE AE (GRASS FAMILY) 



to. Llgnle less than 1 mm. lonj? x. 

 X. Blades velvety on both surfaces; nodes bearded 

 aj. Blades not velvety ; nodes not bearded y 



84. P. annulttm. 



y. Culms crisp-puberulent 58. P. Ashei. 



y. Culms glabrous z. 



54. P. ensifolium. 



56. P. polyanthes. 



57. P. commutatum. 



P. horenle. 



P. mattamuskeeienae 



P. Ashei, 

 P. lancearium. 

 patulum. 



P. scoparium, 

 P. lanuginosum. 

 P. auburn e. 



P. Wilcoxianum. 

 P. ovale. 



69. P. scabriuactUum. 



Spikelets 1.5-l.S mm. long. 



Culm-blades not over 2 cm. long ; spikelets elliptical 

 Culm-blades 6-20 cm. long; spikelets spheroidal. 

 Panicle not more than half as wide as long; blades 



strongly nerved 



Panicle nearly as wide as long ; blades not 



strongly nerved 55. P. sphaerocarpoii 



e. Spikelets 2.2-2. S mm. long. 



Blades cordate, 1.2-2 cm. wide .... 

 Blades not cordate, 0.6-1.2 cm. wide. 



Blades erect ; fruit covered 32. 



Blades spreading ; fruit exposed at summit . . 33. 

 V, Sheaths pubescent a. 

 a. Sheaths puberulent, not pilose. 



Spikelets elliptical, 2.6 mm. long 58. 



Spikelets obovoid-turgid, 2 mm. long. 

 Plants erect or spreading ; blades glabrous above . . 60. 

 Plants prostrate or creeping ; blades puberulent on both 



surfaces 61. P. 



a. Sheaths spreading- or ajtpressed-pilose or velvety 6. 

 b. Plants grajish-velvety througnout. 



Spikelets 2.6 mm. long . . 68. 



Spikelets 1.8 mm. long 44. 



Spikelets 1.3-1.4 mm. long, very turgid , . ,45. 



b. Plants not velvety c. 

 c. Spikelets 2.7-3 mm. long. 



Blades papillose-hirsute on both surfaces . . ,67. 



Blades glabrous or sparsely silky above .... 49. 



c. Spikelets less than 2.5 mm. long d. 

 d, Spikelets ovate, pointed; blades 1.5-2.5 dm. long; pani- 

 cle 1.2-2.5 dm. long ....... 



d. Spikelets obovate or elliptical, blunt; blades and panicle 

 shorter e. 

 e. Pubescence spreading /. 

 /. Spikelets 2.2-2.4 mm. long. 



Plants very villous ; autumnal state prostrate . 

 Plants papillose-hispid on sheaths and sparsely 

 hispid on blades; autumnal state erect . 

 /. Spikelets 1.3-1.9 mm. long g. 



g. Blades stiff, glabrous above or with a few hairs 

 g. Blades pubescent above, or if glabrous lax h. 

 h. Upper surface of blades with erect hairs 3-5 mm, 

 Culms branching veiy early ; spikelets l.S- 



1.9 mm. long 



Culms branching after maturity of primary 

 panicle ; spikelets not over 1.5 mm. long. 

 Axis of panicle loag-jalose .... 

 Axis of panicle nearly glabrous . . . 

 fin Upper surface of blades with short or some- 

 what ai)pressed pubescence. 

 Blades stiff; spikelets obovate .... 

 Blades lax; spikelets elliptical (38) P.huachucae, y. silvicola. 



t, Pnbesesnce not spreading i. 



i. Culms crisp-puberulent or crisp-pubescent; ligule 

 nearly obsolete. 

 Spikelets 1.9 mm. long; blades 5-6 cm. long; 



plants blue-green 



Spikelets 1.7 mm. long; blades 3-5 cm. long; 



plants gray -green 



i. Culms with short or long appressed pubescence j. 

 j. Ligule obsolete or nearly so. 



Spikelets 2.5 mm. long 



Spikelets 2-2.2 mm. long 



$. Ligule 2-3 mm. long. 



Pubescence on lower f heaths spreading 

 Pubescence on lower sheaths appressed. 

 Blades glabrous on ui)per surface; spikelets 



1.2 mm. long 



Blades pubescent on upper surface; spikelets 

 1.5-1.9 mm. long. 

 Spikelets 1.5 mm. long; panicles not over 

 3 cm. long ...... 



Spikelets 1.9 mm. long; i)anicles 3-5 cm. 

 long ... • • . . 



52. P. tHugetorum. 



53. P. columbianum. 



50. 

 51. 



P. 

 P. 



Commonsianum, 

 Addisonii. 



40. P. meridionale. 



87. P leucothrix. 



41. P. oricola. 



42. P. subciUo'iwm. 



