256 BETULA 



B. ALNOIDES, Buchanan- Hamilton var. PYRIFOLIA, Franchet. 



A tall tree, the younger branches bright reddish brown ; young twigs covered 

 more or less densely with pale hairs or down. Leaves ovate, i\ to 5 ins. 

 long, i^ to 3^ ins. wide, rounded or slightly heart-shaped at the base ; pointed, 

 .unequally toothed, each tooth ending in an abrupt, slender point, ciliate, 

 downy on both surfaces, dark dull green above, bright green beneath, covered 

 with minute, lustrous resin-glands ; veins nine to twelve ; leaf-stalk \ to f in. 

 long, downy or nearly smooth, reddish. The young, expanding leaves are 

 of a pretty, red tinge. Fruiting catkins have not yet been seen in this country, 

 but as seen in dried native material, are \\ to 3^ ins. long, cylindrical, \ in. 

 diameter; scales very small, the middle lobe several times larger than the 

 side ones. Nutlets with wings broader than themselves. 



The typical B. alnoides is a Himalayan birch, but the form above described 

 is a native of W. China, whence it was introduced by Wilson in 1901 and 

 again in 1907. Mr Wilson tells me that at 8500 ft. altitude in W. Szechuen 

 he saw it TOO ft. high, with a trunk 12 ft. in girth, so it must be one of the 

 finest of all birches. Our young trees are thriving well, and are curiously 

 distinct in the resinous sheen beneath the leaves, which becomes more 

 apparent as the leaf dries. The young trees introduced by Wilson vary 

 considerably in the downiness of the young shoots. There are numerous 

 plants in cultivation and they are well worth looking after. It is not unlikely 

 this birch may come to be regarded as a distinct species. 



B. DAVURICA, Pallas. 



A tree 60 ft. or more high in nature, the trunk clothed with curling flakes 

 of papery bark, giving it a curious, ragged appearance ; bark at first warm 

 brown ; young shoots sparsely downy, thickly covered with glandular warts. 

 Leaves ovate, 2 to 4 ins. long, i^ to 3 ins. wide ; broadly wedge-shaped or 

 almost straight across at the base, pointed, coarsely and unequally toothed ; 

 dark green and smooth above, downy beneath along the midrib. Veins six 

 to eight pairs ; leaf-stalk about \ in. long. 



Native of Manchuria, N. China, and Corea ; introduced to Kew by the late 

 Dr Bretschneider in 1882, but not a species of much promise, having a 

 failing common to trees of the same region in starting early into growth 

 and being cut back by frost. In upland country it would, no doubt, thrive 

 better. In the curious ruggedness of its bark it resembles B. nigra. 



B. ERMANI, Chamisso. 



A tree said to become 100 ft. high ; bark of the trunk peeling, creamy 

 white ; that of the branches orange-brown ; young shoots not downy, but with 

 numerous glandular warts ; buds nearly ^ in. long, viscid, slender-pointed. 

 Leaves broadly ovate, with a straight or slightly heart-shaped base, taper- 

 pointed, coarsely triangular-toothed ; 2 to 3 ins. long, i^ to 2^ ins. broad ; 

 freely specked with glands on both surfaces, and nearly smooth except for 

 hairs on the midrib, veins, and vein-axils beneath ; veins in eight to eleven 

 pairs ; stalk \ to I in. long, warted. Fruiting catkins barrel-shaped, I to ij 

 ins. long, \ "to in.- wide, the three lobes of the scales broadest at the 

 rounded encls. 



Native of Manchuria, Corea, Japan, and, like many plants from the same 

 region, very liable to injury by spring frosts, owing to its early start into 

 growth. For this reason it does not form a clean trunk, and is subject to 

 fungoid attacks. f| 



Var. NIPPONICA, Maximowicz. A Japanese form with the young shoots 

 leaves, and leaf-stalks less glandular than in the type, the fruiting catkins 



