506 CXXVLI. fc^ALlCACEiE. Populus. 



ness. Leaves elliptical, revolute at edge, obtuse at base, somewhat glaucous 

 beneath, 



32, S. AMBiGUA, Ehrh. Dubiaus Willow. 



Lvs. elliptical, obovate or lanceolate, recurved at the point, entire or 

 remotely denticulate, rugose-veiny beneath, siiky-villous, at length glabrous ; 

 slip, semi-ovate, straight ; aments sessile, briefly pedunculate in fruit ; caps. 

 tomentose, long-pedicellate ; sty. short ; stig. emarginate, — White Mts. 'Tucker- 

 man. A prostrate shrub, with leaves about 1^' by ^', 



33, S. PHYLICIPOLIA, 



Lvs. ovate or lanceolate, remotely repand-serrate, glabrous, glaucous 

 beneath ; slip, semicordate, oblique at apex ; aments bracteate, (^ sessile ; caps. 

 pedicellate, conical-elongated, somewhat silky ; sty. long. — White Mts, T\ick- 

 erman. A handsome, low shrub, spreading, with broad-elliptical, very smooth 

 leaves, the margins repand-serrate. 



34, S, CuTLERi, Tuckerman. (S. Uva-ursi of \st. edit., etc. ?) Cutler's 

 Willow. — Lvs. elliptical, acute or obovate, obtuse at base, glandular-den- 

 ticulate, smooth above, glaucous-smoothish beneath, silky- villous when young; 

 aments pedunculate, cylindric, dense ; caps, ovate-conic, briefly pedicellate, gla- 

 brous ; scales obovate, black, silky ; stig. bifid, lobes at length cleft. — White 

 Mts. Tkickerman. A low or prostrate shrub. 



2. POPULUS. 



Lat, jxypulus, the people ; being often planted by the public ways, 



Aments cylindric ; bracts lacerately fringed ; calycine scales tur- 

 binate, oblique, entire, d Stamens 8 — 30. 9 Ova, superior ; style 

 very short, bifid ; stigma large, 2-lobed ; caps, 2-valved, 2-celled. — 

 Trees of large dimensions. Wood soft and light. Lvs. broad., 'petioles 

 long, often compressed vertically and glandular. Aments lateral, preced- 

 ing the leaves. 



1, P. TREMULoiDES. American Aspen. White Poplar. 



Lvs. orbicular-cordate, abruptly acuminate, dentate-serrate, pubescent at 

 the margin. — Abundant in N. England and in the Middle States, growing in 

 woods and open lands. Stem 25 — 40f in height, with a diameter of 8—12'. 

 Bark greenish, smooth except on the trunk of the oldest trees. Leaves small 

 (2 — 2^' long, and li as wide', dark green, on petioles which are 2 — 3' long and 

 laterally compressed, so that they can scarcely remain at rest in any position, 

 and are thrown into excessive agitation by the slightest breeze. The trembling 

 of the " aspen leaf" is proverbial. Aments plumed with silken hairs, about 2' 

 long, pendulous, appearing in April, long before the leaves. The wood is 

 white, soft and light, of little value. 



2, P, GRANDiDENTATA. Michx. Large Poplar. 



Lvs. roundish-ovate, acute, with large, unequal, sinuate teeth, smooth, 

 villous when young. — Woods and groves in the northern parts of the U. S,, 

 less common than the preceding species. Stem 40f high, with a diameter of 

 If, straight, covered with a smooth, greenish bark. Branches distant, coarse 

 and crooked, clothed with leaves only at their extremities. Leaves 3—5' long 

 and nearly as wide, clothed with thick, white down in spring, but becoming 

 perfectly smooth. The wood is white, soft, and quite durable. May. 



3. P. BETULiFOLiA. Ph. (P. Hudsouica. Michx.) Birch-leaved or Black 

 Poplar. — Lvs. rhomboidal, long-acuminate, dentate, smooth ; young 



branches pilose, — This poplar is found chiefly in the valleys of the Hudson and 

 Connecticut. It is a tree of middle size, with grayish-white twigs, and dark 

 brown buds. Leaves 3^' long and 2 broad. Aments 4—5' long, without hairs. 

 April. 



4. P. BALSAMiFERA. Balsam Poplar. 



Lvs. ovate-acuminate, with close-pressed serratures, white and reticulate- 

 veined beneath: buds resinous, — The balsam poplar, though nowhere abun- 



