146 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Spikelets scarcely more than 3 mm. long. 
Spikelets turgid, blunt; blades mostly less 
than ] cm. wide. ...................---- 170. 
Spikelets not turgid; blades more than 1 cm. 
wide. 
e Panicle narrow, branches ascending; spike- 
Panicle as broad as long, branches spreading. 
Plants glaucous; basal blades conspicu- 
ously ciliate...............-----++--- 185, 
Plants not glaucous; basal blades not cili- 
ate, orat the base only. 
Culms erect, or autumnal form leaning; 
blades symmetrical, broadly cor- 
Culms decumbent; blades usually un- 
symmetrical and falcate; narrowed 
to the scarcely cordate base........ 186. 
Sheaths pubescent. 
Pubescence ascending or appressed. 
Spikelets 3 to 3.2 mm. long; first glume conspicu- 
ously remote.......-...-------------+-+-+- 142. 
Spikelets 3.5 to 4 mm, long; first glume not 
remote...........----- 2-22 eee eee eee eee eee 172. 
Pubescence spreading, sometimes sparse. 
Plants robust, about 1 meter high; blades usually 
2 em, or more Wide........--------------- 189. 
Plants rarely more than 50 cm. high; blades 
rarely over 1.5 cm. wide. 
Panicles about as wide as long; blades ascend- 
ing or spreading. 
Spikelets attenuate at base, 3.5 to 4 mm. 
Spikelets not attenuate at base, not over 3.3 
mm. long. 
Spikelets 3.2 to 3.3 mm. long, blades firm; 
sheaths, or some of them, more or less 
Spikelets not over 3 mm. long; blades 
rather thin; sheaths, or some of them, 
glabrous or sparsely hispid........... 170. 
Panicles narrow, branches erect (sometimes 
ascending in P. wilcorianum), or spreading 
at anthesis only; blades erect. 
Spikelets not over 3 mm. long; blades not 
over 6 mm. wide...........-..-------- 168. 
Spikelets 3.7 to 4 mm. long; blades 8 to 20 
mm. wide. 
Blades papillose-hispid..........-.-.....-174. 
Blades glabrous on both surfaces. ...-..--- 175. 
Spikelets less than 3 mm. long. 
Blades elongated, not over 5 mm. wide; secondary pani- 
cles at the base only or wanting. 
lets on long stiff pedicels............-. 100. 
a) 
. helleri. 
~ 
P, calliphyllum. 
P. mutabile. 
. P. commutatum, 
P. joorw. 
P. malacon. 
P. oligosanthes. 
i] 
P. clandestinum. 
See PEDICELLATA 
(p. 292). 
. P. seribnerianum. 
P. helleri. 
P. wileorianum. 
P. leibergit. 
P. xanthophysum. 
