164 
134 0. Leaves more or less triangular in shape... асла) 135. 
DOME COMO КЫ МШЕ oo e esie IUDA eee ies quip rf augu prm 136. 
135 a. Leaves 2-3 in. broad, branches erect or ascendin 
Lombardy Pris (Populus italica.) 
b. Leaves 3-7 in. broad; branches more or less €—€ 
Co uL. Populus deltoides.) 
136 a. Terminal bud about 1/2 in. or more long, serra poi 
b. Terminal bud r/4 in. or less long, usually rounded 
137 a. Leaves ovate, the margins usually with large pigeon — 1/8 in. or more 
ME ак чыт, Жүр Large-toothed Aspen. (Ро 
b. Leaves round-heart-shaped, 1-3 in. broad, the шеш with rather xdi 
lar teeth usually less than 1/8 in. long. 
American Aspen. (Populus tremuloides.) 
138 a. Leaves fragrant when crushed, not densely hairy when young, the ape 
ПИЛИ tapering. ia coe ЫШЫ alm-of-Gilead. (Populus candicans.) 
b. Leaves not fragrant when crushed, densely hairy when young, the apex 
blunt, the basal lobes often overlapping 
Downy Po plar. (Populus heterophylla.) 
139 a. Branches densely hairy; bark on trunk usually spotted. 
Paper Mulberry. (Broussonetia papyrifera.) 
b. Branches not hairy; bark not ѕроей...........................140 
140 a. Mature leaves dull green on upper suríace, often r ugh. 
Red back. (Morus rubra.) 
b. Mature leaves usually shining and smooth on upper surface. 
White berry. (Morus alba.) 
141 а. Mature leaves shining on both sides, not hairy, ovate to lanceolate; twigs 
— SIGN QUAM PT qu РУ CUP RSEN E Shining Willow. (Salix lucida. i 
ure kavs not shuning on both sides: о улу... 
142 a. ong green on both sides, not NP lighter colored oae 
branchlets pale yellow; leaves 1/4-3/4 in. broad, narrowly lanceolate. 
Black Willow. me nigra.) 
b. Leaves conspicuously lighter colored beneath....................... 143. 
143 а. Leaves 1/4—1/2 in. broad, 3-7 in. long, very vestit beneath; twigs slender and 
ОРОН I eoe ee t Weeping Willow. (Salix babylonica.) 
Trees hot complete dn idees corte аа о оао у Ид 
144 a. Mature leaves 3/4-2 in. broad, very pale beneath. 
Willow. (Salix discolor. a 
b Mature bavos r/e bond, o os ous S eL CELLS 
145 a. Large trees with twigs usually shining yellow.. . White Yellow. (Salix e ) 
b. Slender trees with twigs reddish-green, very brittle at the base. 
Crack Willow. (Salix fragalis.) 
COLUMBIA UNIVERSITY 
Un BEE IE EN 
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