in the latter case, with the two basal lobes very small and directed downwards; membranous; shining, green, and glabrous on both surfaces, except for pubescent tufts in the basal axils beneath; petiole containing latex.
Flowers in corymbs, appearing with the leaves, yellow or greenish-yellow, variable as regards the pubescence of the calyx and the relative length of the petals and sepals. Fruit, variable as regards the length and divergence of the wings.
Acer pictum is the representative in Asia of A. platanoides, and is very uniform in foliage, though it extends over a wide area. Owing, however, to the remarkable variation in the characters of the fruit, it has been usually divided into two species, which cannot be maintained,[1] as there are numerous connecting links; and the different forms are best treated as geographical varieties.
* Branchlets remaining smooth and greenish in the second year. Wings
of the fruit two to three times as long as the carpels.
- 1. Var. colchicum (A. lætum, C.A. Meyer). Asia Minor, Caucasus.
- Leaves, five- to seven-lobed, light green in colour, thin in texture. Fruit-wings usually spreading at a wide angle. In the ordinary form of this variety, the leaves are green on opening. This was introduced[2] in 1838 by Messrs. Booth of Hamburg, plants being in cultivation in the London Horticultural Society's garden in 1840.
- In var. colchicum rubrum, introduced[3] in 1846, the young leaves and young branchlets are deep red in colour.
- 2. Var. cultratum (A. cultratum, Wallich). Persia, Himalayas, Central China.
- Leaves thicker in texture than the last, usually five-lobed, more truncate at the base. Fruit usually with horizontally spreading wings.
- This was introduced[4] from China in 1901 by E. H. Wilson, and is in cultivation at Coombe Wood, where there are plants now 10 feet in height.
- 3. Var. tricaudatum, Rehder.[5] Central China.
- Leaves, three- to four-lobed; basal lobes small or obsolete. This is a peculiar form, with leaves smaller than in the type, scarcely exceeding two inches long by three inches wide; and was introduced[6] by Wilson in 1gor. Young plants at Coombe Wood are already 14 feet high and are growing very vigorously.
- 4. Var. tomentosulum, Rehder.[5] Central China. A rare form with the young leaves covered beneath with dense whitish tomentum.
** Branchlets[7]becoming grey or brown and fissured in the second year.
Wings of the fruit about 1½ times as long as the carpels.
- 5. Var. eu-pictum (A. pictum, Thunberg). Japan.
- Leaves darker green and thicker in texture than in var. colchicum; lobes
- ↑ Cf. Rehder, in Sargent, Trees and Shrubs, i. 178 (1905).
- ↑ Cf. Loudon, Gard. Mag. 1840, p. 632.
- ↑ Nicholson, Gard. Chron. xvi. 375 (1881).
- ↑ Journ. Roy. Hort. Soc. xxix. 354, f. 101 (1904).
- ↑ 5.0 5.1 In Sargent, Trees and Shrubs, i. 178 (1905).
- ↑ Journ. Roy. Hort. Soc. xxix. 354, ff. 100, 102 (1904).
- ↑ Rehder, loc. cit., points out that this character is inconstant, as he has found in several Japanese specimens the bark of the branchlets similar in colour to that of var. colchicum.
