Page:TheTreesOfGreatBritainAndIreland vol03B.djvu/327

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Acer
641

** Leaflets pale beneath.

54. Acer nikoense, Maximowicz. Japan, Central China.
Leaflets three; terminal one about 4 inches long; lateral leaflets slightly smaller and unequal-sided; elliptical, acute; margin crenate, ciliate; under surface villous on the midrib and nerves, scattered pubescent between the nerves, Petioles stout, and like the young branchlets, densely woolly.
A tree, attaining 50 feet in height, with smooth, dark, slightly furrowed bark ; leaves turning brilliant scarlet in autumn. Introduced by Maries in 1881. A tree at Coombe Wood is about 30 feet high.
55. Acer griseum, Pax. Central China.
Leaflets three ; terminal leaflet about 2½ inches long ; lateral leaflets smaller and unequal-sided ; coarsely toothed and ciliate in margin; woolly pubescent on the midrib and nerves beneath. Petioles slender, and, like the young branchlets, pilose.
A tree, attaining 4o feet in height, with bark peeling off like a birch. Introduced by Wilson in 1901. Young plants at Coombe Wood are about 3 feet high. (A.H.)

ACER PSEUDOPLATANUS, Sycamore

Acer Pseudoplatanus, Linnæus, Sp. Pl. 1054 (1753); Loudon, Arb. et Frut. Brit. i. 414, 448, (1838); Willkomm, Forstliche Flora, 749 (1887); Mathieu, Flore Forestière, 37 (1897).

A large tree, attaining about 100 feet in height and 20 feet in girth, Bark’ smooth and greyish on young trees, fissuring and scaling off in large strips on old trunks. Leaves (Plate 206, Fig. 20) 4 to 8 inches in length and width, cordate at the base; lobes five, ovate, acuminate, coarsely and irregularly serrate, lateral lobes larger than the basal ones; sinuses extending about half-way to the midrib, and very acute at the base; upper surface dark-green, shining, glabrous; lower surface paler green and glaucous or sometimes reddish, pubescent along the principal nerves; petiole without latex. The leaves usually turn brownish in autumn, and are often disfigured by black blotches, caused by the fungus known as Rhytisma acerinum, Fr., which, however, does little or no harm to the vitality of the tree.”

Flowers in long pendent racemes, composed of umbellate cymes of three flowers each, the central flower in the cyme usually perfect, the two lateral flowers staminate, with longer stamens and abortive ovaries; pedicels short; sepals five, deciduous, greenish-yellow ; petals five, greenish-yellow, imbricate, inserted at the margin of a fleshy hypogynous disc. Stamens eight, inserted on the disc; filaments subulate ; pubescent below, ovary tomentose. Fruit: keys divergent at a varying


1 In the Edinburgh Botanic Garden there are trees about a foot in diameter, which have remarkably white bark, resembling that of a birch, The largest sycamore in the garden measured, in 1906, 78 feet in height, and 13 feet 7 inches in girth,

2 Cf. Board of Agriculture, Leaflet No. 183.