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POPULUS SALICACE 623 
high and 2-8 feet in diameter, with thick dark longitudinally fissured bark 
and. stout spreading: branches: buds shining and viscid: fewvon broadly 
ovate to oblong-lanceolate, acuminate, narrowed, rounded or subcorcate at 
base, 2-10 inches long, finely puberulent when young, dark green above, 
pale beneath: petioles usually an inch or 2 long: staminate aments dense, 
1-3 inches long, its bracts slightly villous: pistillate aments becoming 6-10 
inches long in fruit, pubescent: capsule subglobose pubescent, 3-4 lines in, 
diameter 3-valved: styles 3, broadly dilated and lobed: seeds light-colored. 
Common along streams, Brit. Columbia to California and the Rocky Mts. 
P. deltoides Marsh Arb. Am. 106. A large tree 100-150 feet high 
and 5-8 feet in diameter, with grayish green bark somewhat rough 
when old: leaves glabrous, broadlv deltoid-ovate, abruptly acuminate at 
the apex, crenulate, truncate at base, 4-7 inches long: petioles flattened 
laterally, stout, about as long as the blades: bracts glabrous, deeply fim- 
briate: staminate aments drooping, 3-5 inches long: pistillate aments 
loosely flowered, becoming 6-10 lines long in fruit: capsule ovoid, acute, 
4-5 lines long, 2 -4-valved, shorter than or equalling their pedicels. Along 
streams, eastern Washington to the Eastern States. 
P. tremuloides Michx FI. ii, 243. Usually a shrub or small tree 
6-30 feet high, but sometimes attaining a height of 10) feet and 3 feet in 
diameter, with smooth light green bark: leaves broadly ovate or orbicular 
short acuminate, finely crenulate and ciliate, truncate, rounded or subeor- 
date at base, 1-3 inches broad: petioles about as long as the blade, flatten- 
ed laterally, causing the leaves to quiver in the slightest breeze ; bracts silky, 
deeply 3-5-cleft into linear lobes: staminate aments 1-3 inches long, the 
pistillate longer, dense: stigma-lobes linear: capsule conic, acute, 2-valved, 
about 3 lines long. Common in moist places, California to Alaska and 
adross the continent. 
SuspcLass 2 ENDOGENAE. 
Stems with the woody fibres scattered irregularly, not form- 
ing a separate zone of annual woody layers between the bark 
and pith. Leaves mostly parallel-veined, alternate, entire, 
sheathing at base. Floral envelopes usually in threes. Em- 
bryo with only one cotyledon. 
SYNOPTICAL KEY to tHE ENDOGENOUS ORDERS. 
A Herbaceous perennials with conspicuous perianth. Ovary 
inferior. 
93 Orchidaceex Leaves mostly flat and not grass-like: flowers perfect, 
irregular: stamens and style coherent: anthers 1 or 2: eapsule 1-celled, 
with 3 parietal placentze: Seeds numerous, with obscure embryo and 
no albumen. 
94 Iridacew Leaves equitant and grass-like: flowers regular, perfect, 
spathaceous: stamens 3, at the base of the perianth: capsule 3-celled: 
embryo distinct, with aibumen. 
B Perianth regular or none. Ovary superior or nearly so. 
* Perianth colored, at least the inner series: carpels united into a 
compound ovary: seeds with albumen. 
95 Smilacew Woody plants climbing by tendrils: flowers dicecious, 
6-parted : anthers 1-celled: fruit a berry. 
