66 POACEAE 
Stem and leaf-sheaths melo 
Spikelets 1.2-1.3 mm. lon 
Spikelets not over rl mm | 
XIX. LANUGINOSA 
Spikelets not over 2 mm. lon 
Plant grayish, velvety-pubese ent. 
Spikelets 1.4-1.5 m Sont. autumnal leaf-blades 
on inted | (gea also P. albemarlense). 
Spikelets 1.8-2 mm. long: autumnal leaf- blades 
at. 
Plant dark-green or olive-green when dry: 
spikelets 1. 9-2 mm. en n 
Plant light-green or yel reen when dry. 
Plant S t, often villous, but not velvety. 
Vernal atii ades glabr pe d nearly so on the 
upper surface, firm in 
Verne leaf-blades. Dubesccnt- n upper surface, 
metimes pi near base and margins 
E s mm. or more long: plants conspicuously 
Spikelets 2.2-2.4 m 
Pubescence on eus and leaf-sheaths horizontally 
spreading: autumnal form freely branching. 
Pubescence on stems and leaf-blades appressed or 
Mu ns E autu mnal form rather sparingly 
Dia 
Spikelets 1-2. mm. long. 
COLUMBIANA 
XX 
Spikelets 2-3.2 mm. long, m m elliptic. 
Winter leaf-blades 5- me . long: spikelets 2 mm. 
ng. 
E 3.2 mm. iene. first glume conspicuously 
ist 
t. 
Spikelets not over 2 2.5 mm. long: first glume not 
distant. 
Spikelets about 2.4 mm. (2.2-2.4 mm.) long: 
panicle open ; branches stiffly spreading. 
Ade 2-2.1 mm. long: pan nicle rather 
ding. 
Spikelets not es 1.9 mm. lon no one turgid. 
Spikelets about 1. "E mna. ion 
Spikelets about 1.5 mm. Tone, 
XXI. SPHAEROCARPA 
Stem spreading: B eR UCM obscurely nerved: panicle 
nearly as broad as long 
Stem ae ect or ascending : e d I strongly 
ved: pan ore o-thirds as 
Droad a Sone. usually less. 
Spikelets. 1 5- m. nos leaf-blades lanceolate, 
he 
dri 1-1.2 mm. once leaf-blades tapering from 
en apex, the upper much smaller than the 
XXII ENSIFOLIA 
Ligule about 1 m ee sheaths or some of them 
sparsely spre eading-pilose . 
Ligules obsolete or near rly So: pubescence if present not 
spreading. 
Leaf-blades prominently white- margined, firm: spike- 
lets densely puberulent. 
67. 
68. 
4. P. leucothriz. 
65. 
P. Wrightianum. 
. P. auburne. 
P. Thurowit. 
P. lanuginosum. 
. P. tennesseense. 
. P. albemarlense. 
. P. meridionale. 
. P. Huachucae. 
. P. villosissimum. 
4. P. pseudopubescens. 
> P. ovale. 
. P. wilmingtonense. 
. P. malacon. 
. P. Commonsianum. 
. P. Addisonii., 
0. P. tsugetorum. 
. P. columbianum. 
. P. sphaerocarpon. 
. P. polyanthes. 
. P. erectifolium. 
. P. curtifolium. 
