BETULACEZ. SILVA OF NORTH AMERICA. 55 
BETULA POPULIFOLIA. 
Gray Birch. White Birch. 
STROBILES cylindrical, short, erect or spreading, short-stalked. Staminate catkins 
usually solitary. Leaves triangular, long-pointed, usually truncate at the broad base, 
lustrous, the petioles slender and elongated. 
Betula populifolia, Marshall, Arbust. Am. 19 (1785).— Betula lenta, Du Roi, Harbk. Bawmz. i. 92 (not Linnzus) 
Du Roi, Harbk. Baumz. ed. 2, i. 144. -— Willdenow, Berl. (1771). 
Baumz. 37, t. 2, £.5; Spec. iv. pt. i. 463.—Borkhausen, Betula excelsa Canadensis, Wangenheim, Nordam. Holz. 
Handb. Forstbot. i. 502. — Persoon, Syn. ii. 572. — Des- 86 (1787). 
fontaines, Hist. Arb. ii. 476. — Poiret, Lam. Dict. Suppl. Betula acuminata, Ehrhart, Beitr. vi. 98 (excl. syn.) 
i. 687.— Du Mont de Courset, Bot. Cult. ed. 2, vi. 408. — (1791). — Moench, Meth. 693. 
Nouveau Duhamel, iti. 204. — Michaux f. Hist. Arb. Am. Betula alba, @ populifolia, Spach, Ann. Sci. Nat. sér. 2, 
ii. 139, t. 2.— Pursh, #7. Am. Sept. ii. 620. — Bige- 
low, Fl. Boston. 231.— Nuttall, Gen. ii. 218; Sylva, i. 
25.— Hayne, Dendr. Fl. 166.—Sprengel, Syst. iii. 
854.— Watson, Dendr. Brit. ii. 151, t. 151.— Hooker, 
Fl. Bor.-Am. ii. 155. — Torrey, Fl. N. Y. ii. 199, t. 112. — 
Emerson, Yrees Mass. 213; ed. 2, i. 243, t.— Die- 
xv. 187 (Revisio Betulacearum) (1341); Hist. Vég. xi. 
233. — Endlicher, Gen. Suppl. iv. pt. ii. 19.— Gray, 
Man. ed. 2, 411. — Regel, Nouv. Mem. Soc. Nat. Mosc. 
xiii. 76, t. 4, f. 19-29 (Monographia Betulacearum). — 
Sargent, Forest Trees N. Am. 10th Census U. S. ix. 
159. 
trich, Syn. v. 303. — K. Koch, Dendr. ii. pt. i. 646.— Betula alba, subsp. populifolia, Regel, Bull. Soc. Nat. 
Lauche, Deutsche Dendr. ed. 2, 274. — Watson & Coulter, Mose. xxxviii. pt. ii. 399 (Gattungen Betula und Alnus) 
Gray’s Man. ed. 6, 471.— Dippel, Handb. Laubholzk. (1865) ; De Candolle Prodr. xvi. pt. ii. 164. 
ii. 171. — Koehne, Deutsche Dendr. 110. 
A short-lived tree, twenty or thirty or exceptionally forty feet in height, with a trunk rarely eighteen 
inches in diameter, and short slender often pendulous more or less contorted branches which usually 
clothe the stem to the ground and form a narrow pyramidal pointed head, often growing in clusters of 
The bark of the trunk is about a third 
of an inch in thickness, dull chalky white on the outer surface and bright orange on the inner, usually 
close and firm, although easily separable into thin plates with dark triangular markings at the insertion 
of the branches; at the base of large trees it is thicker, nearly black, and irregularly broken by shallow 
The branchlets are slender and roughened by small crowded raised lenticels, and, when they 
spreading stems which spring from the stumps of older trees. 
fissures. 
first appear, are resinous-glandular like the unfolding leaves; they gradually grow darker and the 
lenticels become light orange-colored ; before autumn they are dark orange-yellow and lustrous, like 
the young stems, and during the first winter are bright reddish brown, and then growing dark brown 
ultimately become white near the trunk. The leaves are nearly triangular, acuminate and long-pointed 
at the apex, and coarsely doubly serrate with stout spreading glandular teeth except at the broad trun- 
eate or slightly obcordate or wedge-shaped base; they are thin and firm in texture, dark green, lustrous, 
and somewhat roughened on the upper surface early in the season by small pale glands in the axils of 
the conspicuous reticulate veinlets, from two and a half to three inches in length and from an inch 
and a half to two inches and a half in width, with stout yellow midribs marked with minute black glands 
and raised and rounded on the upper side and few yellow obscure primary veins rounded and conspicuous 
above ; they are borne on slender terete petioles covered with black glands, often stained with red on 
the upper side, and from three quarters of an inch to an inch long, and flutter with the slightest breath 
of wind ; in the autumn before falling they turn pale yellow. The stipules are broadly ovate, acute, 
membranaceous, and light green slightly tinged with red. The aments of staminate flowers, which are 
