Graminaceae 61 
M. Leaves flat; lemma 2—3 mm. long, smooth. C. 
P. lettermani Wats. 
MM. Leaves rolled up; lemma 5.5—-6.5 mm. long, smooth. C. 
F. pringlei Scribn. 
MMM. Leaves folded; lemma 3.2—-7 mm. long, scabrous in nearly all. 
N. Glumes obovate, 3—5-veined, silvery-whitish. U. 
P. argentea How. (Silvery Blue-grass) 
NN.  Glumes ovate-lanceolate, 3-veined, not silvery-whitish. C. E. 
P. vaseyochloa Scribn. 
JJ.° Lemma hairy at least on the veins near the base. 
O. Lower glume long-acuminate. U. 
P. acutiglumis Scribn. 
OO. Lower glume acute or obtuse. 
P. Panicle loose, its branches spreading or ascending. 
Q. Leaves rolled up or folded. E. 
P. wheeleri Vas. 
QQ. Leaves flat C. E. (P. invaginata.) 
F. gracillima Vas. (Slender Spear-grass) 
PP. Panicle dense, its branches erect or very short. 
R. Spikelets strongly flattened. 
S. Seashore plant, |—2 dm. high; plant dioicous. U. 
P. douglasii Nees (Douglas Sand-grass) 
SS. Not a seashore plant, 2—4 dm. high; spikelets all alike. W. 
C. E. (See Group 2, O.) 
RR. Spikelets almost terete. 
T. Leaves yellowish-green; spikelets 2—6 mm. long. E. 
P. lucida Vas. (Yellow Spear-grass) 
TT. Leaves dark-green; spikelets 6—10 mm. long. U. E. (2 
buckleyana stenophylla. ) 
P, buckleyana Nash (Bunch Red-top) 
GLYCERIA (Panicularia) MANNA-GRASS 
Perennial (ours) or rarely annual, sometimes aquatic. Leaf-blades usually flat. 
Spikelets several-flowered, terete or slightly flattened; panicle narrow or spreading; ra- 
chilla jointed between the flowers, usually glabrous; flowers perfect except sometimes the 
upper. Glumes unequal, shorter than the lemma, unawned, acute or obtuse, 1—5- 
veined. Lemma smooth or scabrous, unawned, obtuse, convex or flattish on the back, 
conspicuously 3—9-veined, herbaceous, veins not reaching apex; apex hyaline, obtuse, 
sometimes denticulate. Stamens 3. Grain glabrous, grooved, enclosed, not or slightly 
adherent. (Gk. glukeros—sweet; referring to the taste of the grain.) 
A. Spikelets 1—2.5 cm. long, linear. 
B. Lemma scabrous only on the veins, 3—5 mm. long. E. 
G. borealis Pip. (Northern Manna-grass) 
BB. -~ Lemma scabrous all over the back, 6 mm. long. W. E. 
G. fluitans R. Br. (Floating Manna-grass) 
AA. Spikelets 2—-8 mm. long, ovate or oblong. 
C. Lemma 5-veined, broadly scarious-margined. W. C. E. 
G. pauciflora Presl. 
CC. Lemma 7-veined, hardly or not at all scarious-margined. 
a 
