60 Graminaceae 
©. Lemma strongly purple-tinged. W.C. E. (P. purpurascens; Yad 
subpurpurea. ) : 
P. paddensis Wms. (Purple-top Blue-grass) 
OO. Lemma mostly greenish, W.C.E. (P. epilis; P. incurva.) 
F. sandbergii Vas: 
EE. Lateral veins of the lemma nearly parallel, not converging above. 
P. Plant 0.52 dm. high. C. E. (P. leibergit.) 
P. suksdorfii Vas. 
PP. Plant 3—6 dm. high. 
Q. Spikelets much flattened; lemma acute. E. 
P. fendleriana Vas. (Mutton-grass ) 
QQ. Spikelets almost terete; lemma narrow but not acute. E. 
P. lucida Vas. (Yellow Spear-grass) 
GROUP 3 
A. Plant spreading by creeping rootstocks and thus stems not densely tufted. 
B. Seashore plant; leaves rolled up; leaf-blade 5—15 cm. long. W. 
P. confinis Vas. 
BB. Nota seashore plant; leaves folded; leaf-blade 5—15 cm. long. Cake 
P, olneyae Pip. 
BBB. Not a seashore plant; leaves flat; leaf-blade 1—4 cm. long. E. 
. F. curtifolia Seribn. 
AA. Plant without rootstocks and thus stems tufted. 
C. Veins of the lemma pilose below. (See Group 2, BB.) 
CC. Veins of the lemma not pilose, though often somewhat hairy. 
D. Stems coarse, 6—10 dm. high. 
E. Plant green or rarely slightly glaucous; leaves flat or rarely rolled up; pan- 
icle ample. . 
F. Ligule of upper leaf 4—8 mm. long. 
G.. Lemma scabrous; panicle dense. C. E. 
F. canbyi Pip. 
GG. Lemma pubescent; panicle rather loose. E. 
P. leckenbyi Scribn. (Sand Blue-grass) 
FF. Ligule of upper leaf 1—3 mm. long; panicle loose. E. 
P, ampla Mer. 5 
EE. Plant glaucous; leaves rolled up; panicle narrow. 
H. Leaves rolled up; glumes and lemmas unequal. E. 
P. laevigata Scribn. 
HH. Leaves flat or folded; glumes and lemmas nearly or quite the same 
length. 
I. Ligule of upper leaf about 4 mm. long. E. 
P. nevadensis Vas. (Nevada Blue-grass) 
II. Ligule of upper leaf 1—2 mm. long. E. 
P. brachyglossa Pip. 
DD. Stems not coarse, usually less than 6 dm. high, never tall. 
J. Lemma smooth or merely scabrous on the back, not hairy. 
K. Plant 2.5—-7 dm. high. 
L. Lemma minutely scabrous on the back. W. C. E. 
P. saxatilis W. & S. : 
LL. Lemma smooth on the back. E. 
P. curtifolia Scribn. 
KK. Plant 0.5—2.5 dm. high. 
