158 
SILVA OF NORTH AMERICA. 
SALICACEZ. 
POPULUS TREMULOIDES. 
Aspen. Quaking Asp. 
LEAVES ovate or semiorbicular, short-pointed, slightly cordate or truncate at the 
base, finely serrate; petioles elongated, compressed. 
Populus tremuloides, Michaux, F7. Bor.-Am. ii. 243 
(1803). — Nouveau Duhamel, ii. 184, t. 53. — Persoon, 
Syn. ii. 623. — Desfontaines, Hist. Arb. ii. 465. — Du Mont 
de Courset, Bot. Cult. ed. 2, vi. 399. — Michaux f. Hist. 
Arb. Am. iii. 285, t. 8, £. 1. — Willdenow, Hnwm. Suppl. 
67. — Bigelow, FV. Boston. 241. — Poiret, Lam. Dict. 
Suppl. iv. 377. — Hooker, #V. Bor.-Am. ii. 154. — Spach, 
Ann. Sci. Nat. sér. 2, xv. 30 (Revisio Populorum) ; 
Hist. Vég. x. 384.— Torrey, Fl. N. Y. ii. 214; Bot. 
Wilkes Explor. Exped. 468.— Nuttall, Sylva, i. 55.— 
Seringe, Fl. des Jard. ii. 56. — Darlington, F7. Cestr. ed. 3, 
281.— Newberry, Pacific R. R. Rep. vi. pt. iii. 25, 89. — 
paugh, Am. Med. Pl. in Homeopathic Remedies, ii. 
162, t.— Coulter, Man. Rocky Mt. Bot. 339. — Mayr, 
Wald. Nordam. 287. — Watson & Coulter, Gray’s Man. 
ed. 6, 486. — Dippel, Handb. Laubholzk. ii. 197, f. 94. — 
Coulter, Contrib. U. S. Nat. Herb. ii. 419 (Man. Pl. 
W. Texas). — Coville, Contrib. U. S. Nat. Herb. iv. 200 
(Bot. Death Valley Exped.). 
Populus tremula, var., Burgsdorf, Anleit. Anpfi. pt. ii. 174 
(1787). 
Populus trepida, Willdenow, Spec. iv. pt. ii. 803 (1805). — 
Aiton, Hort. Kew. ed. 2, v. 395. — Pursh, #7. Am. Sept. ii. 
618. — Nuttall, Gen. ii. 239. — Sprengel, Syst. ii. 244, — 
Loudon, Arb. Brit. iii. 1649, £. 1510. 
Populus tremuliformis, Emerson, Trees Mass. 243 (1846) ; 
ed. 2, i. 279, t. 
Populus Atheniensis, K. Koch, Dendr. ii. pt. i. 486 (in 
part) (1872). — Koehne, Deutsche Dendr. 80. 
Populus Grzeca, Lauche, Deutsche Dendr. ed. 2, 316 (not 
Aiton) (1883). 
Populus tremuloides, a pendula, Dippel, Handb. Laub- 
holzk. ii. 198 (1892). 
Cooper, Pacific R. R. Rep. xii. pt. ii. 29, 68; Am. Nat. 
iii. 409. — Wesmael, Bull. Féd. Soc. Hort. Belg. 1861, 322, 
£. 2 (Monogr. Pop.) ; De Candolle Prodr. xvi. pt. ii. 325 ; 
Mém. Soc. Sci. Hainaut, sér. 3, iii. 231, t. 3 (Monogr. 
Pop.).— Watson, King’s Rep. v. 327; Pl. Wheeler, 17 ; 
Am. Jour. Sci. ser. 3, xv. 135. — Porter & Coulter, FU. 
Colorado ; Hayden’s Surv. Misc. Pub. No. 4, 129. — 
Brewer & Watson, Bot. Cal. ii. 91. — Rothrock, Wheeler’s 
Rep. vi. 51, 242. — Beal, Am. Nat. xv. 32, f. 1. — Sargent, 
Forest Trees N. Am. 10th Census U. S. ix. 171. — Mills- 
A tree, often a hundred feet in height, with a trunk which occasionally is almost three feet 
through near the ground, but in general is not more than eighteen or twenty inches in diameter, and 
preserves its size with little diminution for fifty feet or more, and with slender, remote, and often 
contorted branches somewhat pendulous toward their extremities, forming a narrow symmetrical round- 
topped head. The bark near the base of old trees is nearly black, from one to two inches in thickness, 
deeply divided into broad flat ridges broken on the surface into small appressed plate-like scales ; 
higher on the trunk and on young stems it is much thinner, pale yellow-brown, orange-green, or 
nearly white, often roughened with interrupted horizontal bands of circular wart-like excrescences and 
frequently marked below the branches with large nearly black raised lunate scars. The branchlets 
are slender and covered with scattered oblong orange-colored lenticels, and when they first appear are 
clothed with caducous pale hairs ; during their first year they are bright red-brown and very lustrous, 
but gradually turn a light gray tinged with red and then become dark gray, and for two or three years 
are much roughened by the large elevated leaf-scars. The leaf-buds are slightly resinous, conical, acute, 
slightly incurved, about a quarter of an inch in length, narrower than the more obtuse flower-buds, and 
covered with six or seven lustrous glabrous red-brown scales scarious on the margins, and more or less 
tinged with green and sometimes puberulous toward the base, the lowest emarginate. The leaves are 
ovate or semiorbicular, three-nerved, abruptly narrowed at the apex into short broad points, and regu- 
larly serrate with small incurved callous gland-tipped teeth except at the broad slightly cordate truncate 
or rarely wedge-shaped base; when they unfold they are glabrous, light green and lustrous, and ciliate 
