SILVA OF NORTH AMERICA. BETULACEZ. 
48 
found in the forests of northern India,! and four or five others are endemic in northern China’ and 
Japan.? The type is an ancient one; its traces appear in the cretaceous rocks of the Dakota group 
formation, and later, during the tertiary period, it spread over the central plateau and the northwest 
coast of North America,‘ and abounded in Europe, where paleontologists have recognized in the eocene, 
paleocene, and especially in the miocene, the remains of numerous species, the direct ancestors of those 
now living.® 
The compact straight-grained wood of several species of Betula is valued by the cabinet-maker or 
is employed in the manufacture of spools, shoe-lasts, and other small articles; it burns with a bright 
clear flame and is largely used for fuel and in the making of charcoal. From the bark, which separates 
from the young stems and from the branches of several species in thin layers and is impervious to 
water, light canoes, shoes, boxes, cords, and a covering for buildings are made. The bark contains an 
astringent principle and a resinous balsamic oil sometimes used in tanning leather.’ In North America 
the bark and leaves of the different species of Betula are esteemed as domestic remedies for chronic 
diseases of the skin and for rheumatism and gout, and the empyreumatic oil obtamed from the inner 
bark by distillation is used externally and internally for the same purpose.’ The sweet sap of many of 
the species is used as a beverage, and is sometinies made into wine. 
Betula is not much injured in America by insects,* although many species are found on it, nor 
1 Brandis, Forest Fi. Brit. Ind. 457.— Kurz, Forest Fl. Brit. 
Burm. ii. 476. — Hooker f. Fl. Brit. Ind. v. 599. 
2 The Birch is a common tree on the high mountains of northern 
China, three or four species having been recognized which resemble 
those of Manchuria, where several Birch-trees, principally varieties 
of European and Siberian species, form a considerable portion of 
vast forests (Maximowicz, Mém. Sav. Etr. Acad. Sci. St. Pétersbourg, 
ix. 249, 391 [Prim. Fl. Amur.]). 
8 In Japan Betula does not form great forests, but several species 
are abundant at high elevations in Hondo and among the decidu- 
ous-leaved trees of Yezo. The common species of central Japan is 
Betula Ermani, Chamisso (Linnea, vi. 537, t. 6, f. D. [1831]), an 
inhabitant also of Saghalin and Manchuria, and, as it stands among 
the dark Hemlocks in the great coniferous forests covering the 
high mountain slopes of central Japan, is one of the most beautiful 
of Birch-trees, with its silvery stem and wide-spreading bright 
orange-colored branches from which the bark separates in great 
plates. 
Still more beautiful, however, is Betula Maximowicziana, Regel 
(De Candolle Prodr. xvi. pt. ii. 180 [1868], Betula Maximowiczii, 
Regel, Bull. Soc. Nat. Mosc. xxxviii. pt. ii. 418, t. 6, f. 1-8 [Gat- 
tungen Betula und Alnus] [not Ruprecht] [1865]), which finds its 
home on the hills of central Yezo, and is a noble tree eighty or 
ninety feet in height, with a trunk often three feet in diameter, cov- 
ered, except at the very base, with smooth orange-colored bark, 
dark red-brown branches, thin lustrous cordate leaves from four to 
six inches long and often more than four inches wide, and racemose 
strobiles. The bark, which separates in large plates from the 
trunk, is very durable and is used by the Ainos in the manufacture 
of numerous articles of domestic use. 
Betula alba in at least three forms is common in northern and 
central Japan, where four other species are believed to occur, 
although none of them are common or well known in any part of 
(See Sargent, Forest Fl. Japan, 61.) 
* Lesquereux, Rep. U. S. Geolog. Surv. vii. 137, t. 17, £. 18-23 ; 
vill. 36, 150, t. 27, f. 11, t. 28, £. 7,8; 242, t. 50, f. 12, t. 51, £. 6 
(Contrib. Fossil Fl. W. Territories, ii., iii.). 
5 Saporta, Origine Paléontologique des Arbres, 145. — Zittel, 
Handb. Paleontolog. ii. 409. 
the empire. 
6 Hohnel, Die Gerberinden, 52. 
7 Nat. Dispens. ed. 2, 286.— Johnson, Man. Med. Bot. N. Am. 
252. — U. S. Dispens. ed. 16, 1728. 
8 In the fifth report of the United States Entomological Com- 
mission, published in 1890, one hundred and seventeen species of 
insects known to affect the Birches of eastern North America are 
recorded. Their number has already been considerably increased 
and there is probably still much to learn in regard to the insects 
Many of those found 
on the Birch also live upon Oaks, Alders, Willows, and other trees. 
which attack these trees in North America. 
No especially destructive indigenous borers have been noticed in 
the trunks of Betula in North America, although Chrysobothris 
6-signata, Say, Leptura vagans, Olivier, and other Coleoptera some- 
times injure the trunks. Of the numerous insects which feed upon 
the foliage of Betula few are known to be persistently injurious. 
The common Fall Web-worm, Hyphantria cunea, Drury, is one of 
the most troublesome, and several other species of Bombycide live 
upon the American Birches, but rarely appear on them in great 
numbers. Species of Noctuide are abundant on these trees, more 
than a dozen species belonging to the genus Apatela alone having 
been recorded. Tortricide are numerous, rolling and twisting the 
leaves in various ways, according to the species, and Lithocolletis 
betulivora, Walsingham, and other leaf-miners live within the paren- 
chyma of the leaves. 
Birch-trees are sometimes injured by Saw-flies like Crasus lati- 
tarsus, Norton, and Hylotoma dulciaria, Say, which feed gregari- 
ously on the foliage ; Athysanus variabilis, Fitch, and other Leaf- 
hoppers are often common upon Birches, and scale insects and 
aphids of various species sometimes damage them. Callaphis betu- 
lella, Walsh, has been described as abundant on Betula nigra in 
Illinois, and Hormaphis papyracee, Oestlund, forms long folds or 
corrugations between the veins of the leaves of the Canoe Birch. 
Minute galls, generally considered the work of Phytoptus, are 
sometimes found in large numbers on the leaves of some of the 
species, and a species of Phytoptus, or mite, arrests the growth of 
buds and twigs, causing them to become distorted, and forms large 
dense dark clusters or bunches in the trees. Betula lenta seems 
particularly liable to be affected in this way. 
