66 Graminaceae 
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P. Glumes scabrous. W.E. (B. marginatus latior.) 
B, marginatus Nees 
PP. Glumes glabrous or scabrous on the veins only. W. 
B. marginatus seminudus Shear 
OO. Leaves linear, somewhat rolled up, finely pubescent, not pilose. E. 
B. subvelutinus Shear 
MM. Lemma-awn more than 7 mm. long. 
Q. Lower rays of the panicle drooping. .W. C. 
B. sitchensis Trin. 
QQ. Lower rays of the panicle not drooping. W. E. 
B. carinatus H. & A. 
LL. Spikelets terete or nearly so. 
R. Lemma-awn |10—16 mm. long; lower glume | -veined. 
S. Annual; leaves and sheaths pubescent; lemma 5-veined. E. 
B. tectorum ihe (Downy Brome) 
SS. Perennial; leaves and sheaths glabrous or pilose; lemma 7-veined. 
T. Sheaths and leaves glabrous. (3B. vulgaris eximus.) C. E. © 
B. eximus Pip. 
TT. Sheaths and leaves more or less pilose. W.C. E. (B. eximus 
umbraticus; B. vulgaris; B. vulgaris robustus. ) 
B. eximus robustus Pip. 
RR. Lemma-awn 4—8 mm. long. 
U.  Glumes glabrous or merely scabrous. 
V.  Panicle-branches not drooping. C-. 
B. suksdorfii Vas. 
VV. Panicle-branches drooping. 
W. Lower glume |-veined; rootstocks none. W. E. (B. richard- 
~ sont pallidus.) 
B. richardsonij Link. 
WW. Lower glume 3-veined; rootstocks present. E. 
: B. laevipes Shear 
UU. Glumes pubescent or pilose. 
X. Stem 9—18 dm. high; pubescent below the panicle; leaves 20—-25 
cm. long, 8—14 mm. wide; panicle-branches drooping. W. 
. B. pacificus Shear 
XX. Stem 2—9 dm. high, glabrous except at the nodes; leaves 2.5—17.5 
cm. long, 2—6 mm. wide; panicle-branches not drooping . 
Y. Lower glume 1|-veined; lemma !0—14 mm. long, pubescent; lem- 
ma-awn 3—5 mm. long, bent and twisted; perennial. W. (Trise- 
tum barbatum. ) 
B. barbatoides Beal 
YY. Lower glume 3-veined; lemma 7—9 mm. long, pilose; lemma- 
awn 6—8 mm. long, straight; annual. W. E. 
B. hordeaceus L. (Soft Brome) 
AA. Lemma-awn | 7—25 mm. long; plant annual or biennial; lower glume’ | -veined. 
Z. Stem somewhat pubescent toward the top; panicle dense, ovoid, head-like. E. 
B. rubens L. 
ZZ. Stem glabrous; panicle loose, at least its lower branches spreading. 
a. Spikelets 3.6—5 cm. long; glumes somewhat scabrous. U. 
B. midritensis L. 
aa. Spikelets 2.5—-3.5 cm. long; glumes glabrous. W. E. 
B. sterilis L- 

