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of Prunus serotina. It produces seed once in three or four years, and does not bear shade well, though young trees will sprout from the stump. The timber is heavy, hard, and strong, dark brown in colour, and takes a good polish.

1 saw a very fine tree of this species in a garden at Lancaster, Massachusetts, 62 by 10 feet, dividing at 3 feet into four stems, which were covered with a very yellow and grey bark.

Betula lenta was introduced into England in 1759, according to Loudon. We are not aware that it has anywhere attained a large size, except at Oakly Park, near Ludlow, the property of the Earl of Plymouth, where on a rich sheltered flat on the banks of the Teme, I found a tree of considerable age, which in August 1908 measured about 60 feet by 4 feet 9 inches. The trees in Kew Gardens are about 20 feet in height. A specimen at High Canons, Herts, measured 36 feet high by 4 feet 2 inches in girth, and bore fruit in 1907. Another at Bicton, 38 feet by 3 feet 5 inches, is growing in the Arboretum walk, near the Paper Birch.

Beer is sometimes obtained in America by fermenting the sugary sap of this tree. Oil of birch, which is made on a considerable scale in Pennsylvania, is a more important product. This is obtained by distilling the wood,’ one ton of which yields about 4 lbs. of oil. This oil is nearly identical, both in chemical and physical properties, with oil of winter-green, which is manufactured in the same district ; and commercial oil of winter-green is a mixture of the two oils in varying proportions. (H.J.E.)

A tree, occasionally attaining 4o feet in height and 3 or 4 feet in girth, more commonly shrubby, with many branching stems. Bark about % inch thick, dark brown, shining, not separating into thin layers, marked by pale brown horizontal lenticels. Young branchlets viscid, densely covered with resinous glands, inter- spersed with long, pale hairs; older branchlets dark in colour and roughened with the persistent glands. Leaves about 1½ inch long, and 1 to 1½ inch broad, thin in texture, broadly or narrowly ovate; rounded, truncate or subcordate, and often unequal at the base; acute at the apex; margin ciliate, sharply and doubly serrate ; nerves six to eight pairs; both surfaces glandular with scattered long hairs, at first paler beneath, becoming glabrescent ; petiole, ½ inch, glandular, glabrescent.

Fruiting-catkins, about 1 inch long, ¼ inch in diameter, cylindrical, on slender glandular stalks; scales pubescent, ciliate, with the three lobes triangular and nearly equal in size, the lateral lobes divergent ; nutlets with broad wings,

This species is readily distinguished by its conspicuously glandular branchlets and its small, thin leaves, which are variable in width, and in the form of the base.

1 Cf. article by H. Trimble in Garden and Forest, viii. 303 (1895), where the Process is described. The oil of birch is contained in the inner bark only; and on this account the wood used in distillation is obtained from small trees, usually coppice shoots.