684 The Trees of Great Britain and Ireland 
ACER NEGUNDO, Asu-LeaveD Mapiez, Box ELDER 
Acer Negundo, Linneus, Sp. Pl. 1056 (1753); Sargent, Silva N. Amer. ii. 111, t. 96 (1892), and 
Trees N. Amer. 641 (1905). 
Negundo aceroides, Moench, Meth. 334 (1794). ee 
Negundo fraxinifolium, Nuttall, Gen. Amer. i. 253 (1818) ; Loudon, Ard. e¢ Prut. Brit. i. 460 
(1838). 
A tree attaining in America 70 feet in height and 12 feet in girth; bark 
deeply fissured into broad rounded ridges. Young branchlets green or glaucous, 
glabrous. Leaves (Plate 205, Fig. 2) pinnate, turning yellow in autumn. Leaflets, 
three or five, stalked, ovate or oval, rounded or cuneate at the base, acuminate 
at the apex, serrate or toothed above the middle, often three-lobed ; upper surface 
bright green and glabrous; lower surface pale green and with slight pubescence 
on the midrib and nerves; rachis glabrous. 
Flowers dicecious, without petals, appearing with the leaves, from buds in the 
axils of the leaf-scars of the previous season, staminate flowers in fascicles, pistillate 
in narrow pendulous racemes. Fruit, with narrow acute nutlets, diverging at an 
acute angle, and thin reticulate, straight or falcate wings. 
In winter, the terminal buds are about } inch long, acute, with four tomentose 
ciliate external scales; lateral buds appressed to the twigs, with two outer visible 
scales ; opposite leaf-scars united around the twig, narrowly crescentic, three-dotted, 
fringed with hairs on the margin. 
VARIETIES 
The species, extending over a vast territory, varies considerably in the wild 
state, the typical form described above occurring in the eastern part of its distribution. 
Farther west, in Colorado, Utah, and New Mexico, the branchlets and leaves become 
pubescent ; and in California, an extreme form is met with, which is often considered 
to be a distinct species :— 
1. Var. caltfornicum, Wesmael, Bull. Bot. Soc. Belg. 43 (1890); Sargent, 
Garden and Forest, iv. 481 (1891), Selva N. Amer. ii. 112, t. 97 (1892), and Zvees 
NV. Amer. 643 (1905). 
Acer californicum, Dietrich, Syn. ii. 1283 (1840). 
Negundo californicum, Torrey and Gray, . NM. Amer. i. 250, 684 (1838). 
This is distinguished, according to Sargent, by its darker-coloured bark; buds 
covered with dense tomentum ; short pale persistent pubescence on the branchlets 
and ripe fruit; leaflets three, larger, more coarsely serrate, and more frequently 
lobed than in the type, and coated beneath with pale pubescence. As seen in 
cultivation at Kew, the leaflets are usually five and not three; and in the wild state, 
5-foliolate leaves are occasionally met with, as in a specimen in the Kew herbarium 
collected by Lobb in California. The pubescence on the leaflets beneath is most 
strongly marked on the midrib and nerves, is whitish in colour, and forms prominent 
