pubescence. Leaf-scars and stipule-scars as in the common alder. Buds reddish- brown, ovoid, conspicuously stalked, with two external scales, finely pubescent on the surface and only slightly glandular. Pith triangular or three-lobed.
The grey alder exhibits in the wild state considerable variation in the shape and pubescence of the leaves, and the cones may be sessile or shortly stalked. Many varieties are mentioned by Winkler and Schneider, most of which are scarcely worth discriminating ; but the following are noteworthy :—
1. Var. argentata, Norrlin. Leaves silvery on both surfaces, and covered with a dense silky pubescence. Observed in Finland, Silesia, Saxony, and Switzerland.
2. Var. glauca, Regel. Leaves bluish-green and nearly glabrous beneath.
3. Var. orbicularis, Callier. Leaves small, almost orbicular, with five pairs of lateral nerves, wild in Silesia. This is occasionally cultivated under the name of var. parvifolia; but var. parvifolia, Regel, which occurs in Sweden and Finland has still smaller leaves, only ½ inch in length, and ovate in shape.
4. Var. acuminata, Regel.’ Leaves (Plate 268, Fig. 9) divided more than half- way to the midrib, into three to six pairs of long, narrow, triangular, serrate segments. This form has been observed wild in Sweden, and has been much confused with another wild variety in the same country, var. pzxnatzfida, Wahlenberg,’? which resembles in the shape of the leaves A. g/ucinosa, var. iuctsa; and has not been seen by us in cultivation. Var. acuminata is common in gardens, and is usually known as var. znctsa or var. pinnatifida.
5. Var. aurea, Schelle. Leaves and fruit yellow. This variety is growing well at Aldenham, and is striking in appearance.
6. Var. montrosa, Dippel. A dwarf shrub, with the tips of the branches ribbon- like and fasciated, which originated in Spath’s nursery. In cultivation at Aldenham.
Distribution
The grey alder is widely distributed throughout the greater part of Europe and the Caucasus. It is also met with in North America, where, however, it is only a shrub, commonly growing in swamps and on river banks, and forming dense thickets rarely more than 10 or 12 feet high, and is spread throughout British territory from Newfoundland to the eastern base of the Rocky Mountains, descending in the United States to New York, Pennsylvania, Wisconsin, and Nebraska.
Alnus incana is replaced in northern and eastern Asia by two closely allied species: A, hirsuta,® Turczaninow, not in cultivation, a native of Siberia, Kamtschatka, Manchuria, Saghalien, and Japan; and A. ¢inctoria, Sargent,‘ which is confined to Manchuria and Japan. The latter species differs mainly from A. incana, in the larger size and different shape of the leaves, which are broadly
1 Mem. Soc. Nat. Mosc. xiii, 158, t. 17, f. 8 (1861).
2 Fl. Suec. 622 (1824).
3 Bull. Soc. Nat. Mose. 1838, p. 101. Alnus incana, var. hirsuta, Spach.
4 Garden and Forest, x. 472, f, 59 (1897). Alnus incana, var. glauca, Shirasawa, Icon. Ess. Forest. Japon, t. 19, ff. I-17 (1900). This species is known in Japan as yama-harinoki, or mountain alder, and is much used for making small articles in the Hakone mountains. Cf. Rein, Industries of Japan, 239, 336 (1889).
