CHAP. CIV. 



i?ETULA*CE,E. YLNUS. 



1679 



The bark, at the 



species we think only varieties, as we have indicated by 



putting the letter g. in parentheses. 



Description. The alder, in a wild state, even in favour- 

 able situations, is seldom seen higher than 40 ft. or 50 ft. ; 

 but in uncultivated grounds, and in good soil near water, 

 it will attain the height of .50 ft. or GO ft., and upwards. 

 This is not only the case with the species, but with the 

 variety A. g. laciniata, which forms a handsome pyramidal 

 tree; which, at Syon, has attained the height of 03 ft., 

 and at Woburn Farm, near Chertsey, is still higher. The 

 bark of the common alder, in oldish trees, is nearly black, 

 and full of clefts ; the colour of the wood is white before 

 the tree is cut down ; but, immediately on being cut, the 

 surface of the wound becomes of a deep red ; soon fading, 

 however, into the pale flesh-colour, which the whole of 

 the wood of this tree, when cut down, takes when dry, and 

 retains ever afterwards. The wood is homogeneous, tender, 

 and without much tenacity. The branches, when they 

 are young, and the tree is in a state of vigorous growth, 

 have a triangular form ; but, when mature, they are round, 

 rising of the sap, separates from the wood with very great facility. The 

 leaves, when in the bud, are folded in the manner of a fan, very glutinous, 

 and completely enclosed by two oblong 

 stipules of a whitish green. They are from 

 3 in. to 4 in. long, and nearly as broad. 

 The petiole is about 1 in. long, and pro- 

 longed on the disk of the leaf, in the form 

 of a very prominent nerve on the under 

 side, from which proceed to the right and 

 left other prominent nerves, in each of the 

 axils formed by which is a little tuft of 

 cottony hair. The characteristics of the 

 leaves of this species, as compared with 

 those of other species of the genus, and 

 especially of A. incana, is, that they are 

 always rounded at the summit, and never , 

 pointed ; though this distinction does not ^ 

 hold good when applied to some of the 

 varieties, such as A. g. laciniata. The leaves are of a deep dark green ; and both 

 the young shoots and leaves are covered with a glutinous substance, more espe- 

 cially in the early part of summer. The male catkins are cylindrical, like those 

 of the birch, and appear in the autumn; while the female ones, which are on 

 branched footstalks, are of a short conical form, like a small fir cone, and 

 are produced in spring along with the leaves. On Mount Caucasus, Pallas 

 informs us, the female catkins come out about the end of February; but, in 

 the north of Russia, in March and April. The rate of growth of the alder, 

 in a favourable soil and situation, is about 2 ft. or 3 ft. a year for four or 

 five years ; so that a tree 10 years planted will frequently attain the height of 

 20 ft. or 25 ft. ; and at 60 years the tree is supposed to have arrived at 

 maturity. The roots are creeping; and sometimes, but rarely, they throw 

 up suckers. The shade and fallen leaves of this tree are not injurious 

 to grass. 



Geography, History, Jyc. The common alder is the most aquatic of Euro- 

 pean trees, being found in wet swampy grounds, throughout the whole of 

 Europe, in situations too moist for even the willow and the poplar. In 

 meadows, and by river sides in the plains, it becomes a considerable tree ; but 

 on mountains, and in the most northerly parts of Sweden, it diminishes to a 

 shrub. It is found in the west, east, and north of Asia rmd in the north of 



5r 



