1692 ARBORETUM AND FRUTICETUM.: , PART III. 
sidered by many botanists as a species, and 
distinct enough in appearance, we have no 
hesitation whatever in pronouncing it to be 
merely a variety. 
¥ B. a.4 pontica; B. pontica Lodd. Cat., ed. 1836 ; 
and our jig. 1549.; has the leaves somewhat 
larger than the species, and appears of more 
robust growth. There is a tree of this kind in 
the Oxford Botanic Garden, which, 40 years 
planted, is 45 ft. high; the diameter of the 
trunk 1 ft. 11 in., and of the head 30 ft. At 
Croome there is a tree, which, 40 years 
planted, is 70 ft. high ; and in the Glasnevin 
Botanic Garden, one 35 years old, which is 
38 ft. high. The plants in Messrs. Loddiges’s 
collection are quite young, and not above 
3 ft. or 4 ft. in height. 
¥ B. a. 5 urticifolia, B. urticifolia Lodd. Cat., has 
the leaves deeply laciniated, serrated, and hairy. 
* B. a. 6 dalecdrlica L. Supp., 416., is described by the younger Linnzus, as having its leaves 
almost palmate, with the segments toothed; ‘‘ cut like those of hemp,” according to 
Bosc. 
B. a. 7 macrocdérpa Willd. has the female catkins twice as long as those of the species. 
B. a. 8 folits variegatis Dumont has the leaves blotched with yellowish;white. 
Other Varieties. B. populifolia and B. datrica, given below as species, 
are, we think, as much varieties as the preceding sorts; for, though B. popu- 
lifdlia will come tolerably true from seed, yet itis often produced from seeds 
of the common birch. #2. datrica appears to be a variety of B. alba, stunted 
from the climate in which it grows; and the same observation will apply 
to B. sibirica, and some others, enumerated in the Catalogue of Messrs. 
Loddiges for 1836. B. excélsa and B. nigra of some of the London gar- 
dens are mere varieties of the common birch, and quite distinct from the 
species described by botanists under these names, which are natives of 
America. (See Gard. Mag., vol. xi. p. 502. 689.) There are some other 
sorts in the collection at Messrs. Loddiges’s; such as B. undulata, 2B. 
Thouiniana and B. Fischéri, which appear to us to belong to B. alba; but, 
the plants being exceedingly small, we are not able to determine this with 
certainty. B. laciniita being merely a cut-leaved variety of B. populifolia, we 
have included it under that head; as we have the sort named B. péndula, 
in the collection of the Messrs. Loddiges. We prefer, in this case, as in 
similar ones, giving varieties which have been generally considered species 
as such, merely indicating our opinion by a letter in parentheses, for the 
sake of disposing of the synonymes. There are some varieties of a trifling 
nature given by Linnzus in his Flora Suecica : such as one with a rounder 
leaf than the species, and pendent branches ; one with a white, broad, and 
acuminate leaf; one with brittle branches, and a blackish woolly leaf; one 
(B. saxatilis torminalis) with an oblong leaf}; and, lastly, the dwarf birch, 
probably the B. pumila of Lodd. Cat. These varieties are recorded in 
Martyn’s Miller ; but, unless we are right in conjecturing B. pumila to be 
the last, we have not seen any of them. Dr. Agardh mentions “ three 
singular varieties with laciniated leaves (B. hybrida Mench) near Fahlun. 
(Gard. Mag., vol. xii. p. 63.) The birch varies so much from seed, that 
scarcely any limits can be given to the number of sorts that might be 
selected from a seed-bed. In extensive birch forests, also, whether in the 
rocky scenery of Sweden, the bogs in the north of Russia, or on the hills of 
Germany, full-grown trees may be seen, as various in their foliage and habit 
of growth as the young plants in seed-beds. For this reason, we are in- 
clined to think that there are only two European species of birch, B. dlba 
and B. nina; and four American species, B. papyracea, B. excélsa, B. 
lénta, and B. nigra. 
