LXIX. BETULA‘CEZ: BE’TULA. 839 
t B. a. Surticifolia, B. urticifolia Lodd. Cat.— Leaves deeply laciniated, 
serrated, and hairy. 
¥ B. a. 6 dalecarlica L. Supp. 416. — Leaves almost palmate, with the 
segments toothed; “cut like those of hemp,” according to Bosc. 
* B. a. 7 macrocérpa Willd, — Female catkins twice as long as those of 
the species. 
¥ B.u. 8 foliis variegatis Dumont. — Leaves blotched with yellowish 
white. 
Other Varieties. B. 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 gardens 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.) B. undulata, B. Thouinidna, and B. Fischeri 
also appear to us to belong to B. alba; but the plants being exceedingly 
small, we are not able to determine this with certainty. 
The rate of growth of the common birch is considerable when the tree is 
young, averaging from 18 in. to 2 ft. a year for the first 10 years ; and young 
trees cut down to the ground often make shoots 8 or 10 feet long in one season. 
The duration is not great, the tree attaining maturity, in good soils, in from 
forty to fifty years; but, according to Hartig, seldom lasting in health till it at- 
tains a hundred years. The wood is white, shaded with red; of a medium 
durability in temperate climates, but lasting a long time when it is grown in the 
extreme north. The grain of the wood is intermediate between coarse and 
fine. It is easily worked while green ; but it chips under the tool when dry. 
It weighs, when green, 65 lb. 6 0z.; half-dry, 56 lb. 6 oz.; and dry, 45 lb. 1 oz. 
Though the birch may be propagated by layers and even by cuttings, yet 
plants are not readily produced otherwise than by seed; and those of certain 
varieties, which are procured from layers or by inarching, never appear to 
grow with the same vigour as seedlings. Birch seed ripens in September and 
October, and may be either gathered and sown immediately, or preserved in 
a dry loft, and sown in spring. Sang directs particular attention to be paid 
to gathering the seeds only from weeping trees ; aoe 
and this we know to be the directions given to ‘ 
the éollectors employed by the nurserymen in 
the north of Scotland. If the seeds are to be / 
sown immediately, the catkins may be gathered 
wet; but, if they are to be kept till spring, 
they ought not to be gathered except when 
quite dry ; and every day’s gathering should be 
carried to a dry loft and spread out thinly, as 
they are very apt to heat when kept in sacks 
or laid up in heaps. The seeds should be sown 
in very fine light, rich soil, in beds of the usual 
width, and very slightly covered. Boutcher 
says : —“ Sow the seeds and clap them into the 
ground with the back of the spade, without any 
earth spread over them, and throw a little peas 
haulm over the beds for three or four weeks, till 
the seeds begin to vegetate. The peas haulm ‘ 
will keep the ground moist, exclude frost, and ap* 
prevent the birds from destroying the seeds.” y 
(Treat. on Forest Trees, p. 113.) “ It is scarcely : 
possible,” Sang observes, “ to cover birch seeds too little, if they be covered 
atall.” The plants, if sown in autumn, will come up in the March or April 
following. ih sown in spring, they will come up in May or June; which, in 
very cold climates, is a as ig If any danger is apprehended 
H 
