Part 58

BARK.--Twigs lustrous, brown or gray, becoming slate colored on the branches; trunk gray or brownish, smooth or flaking off in short scales.

WOOD.--Moderately heavy, hard, compact, brownish, with white sapwood.

NOTES.--Exotic from Europe. Much planted in our cities, where it is thrifty, but short-lived. The crown is rather too broad for planting anywhere except on our widest streets. The leaves last two weeks longer in autumn than do those of our native maples.

1. Winter twig, × 1. 2. Leaf, × 1/2. 3. Staminate flowering branchlet, × 1/2. 4. Staminate flower, enlarged. 5. Pistillate flowering branchlet, × 1/2. 6. Pistillate flower, enlarged. 7. Fruit, × 1.]

+ACERACEAE+

+Boxelder. Ash-leaved Maple+

Acer negundo L. [Negundo aceroides Muench.]

HABIT.--A sturdy little tree 30-50 feet high, with a trunk diameter of 1-2 feet. Trunk often divides near the ground into several stout, wide-spreading branches, forming a broad, unsymmetrical, open crown.

LEAVES.--Opposite, pinnately compound. Leaflets 3-5 in number, 2-4 inches long, 1-1/2-2-1/2 inches broad; ovate or oval; nearly entire, irregularly and remotely coarse-toothed above the middle, or sometimes 3-lobed (often giving the leaflet a jagged outline); apex acute, base variable; glabrous or somewhat pubescent at maturity, with prominent veins. Petioles slender, 2-3 inches long, the enlarged base leaving prominent crescent-shaped scars partly surrounding the winter-buds.

FLOWERS.--April, before or with the leaves; dioecious; small, yellow-green; the staminate in clusters on long, thread-like, hairy pedicels; the pistillate in narrow, drooping racemes; calyx hairy, 5-lobed; corolla 0; stamens 4-6; ovary pubescent.

FRUIT.--Early summer, but hanging until late autumn or early spring; narrow, flat, winged samaras, in pairs, clustered in drooping, racemose clusters.

WINTER-BUDS.--Terminal bud 1/8-1/4 inch long, acute, inclosed in two dull red scales, often hoary or minutely pubescent; lateral buds obtuse, appressed.

BARK.--Twigs greenish to purple, glaucous; trunk pale gray or light brown, deeply cleft into broad ridges.

WOOD.--Light, soft, close-grained, weak, creamy white, with thick, hardly distinguishable sapwood.

DISTRIBUTION.--Lower Peninsula as far north as Saginaw Bay.

HABITAT.--Banks of streams and borders of swamps. Prefers deep, moist soil.

NOTES.--Accommodates itself to almost any situation. Easily transplanted. Much planted for shade and ornament. Fast-growing, but short-lived.

+SUMMER KEY TO THE SPECIES OF AESCULUS+

a. Leaflets usually 5; foliage ill-smelling when bruised; bark broken into thick plates; prickly bur about 1 inch in diameter. A. glabra, p. 199.

aa. Leaflets usually 7; foliage not ill-smelling when bruised; bark broken into thin plates; prickly bur about 2 inches in diameter. A. hippocastanum, p. 197.

+WINTER KEY TO THE SPECIES OF AESCULUS+

a. Terminal bud about 2/3 inch long; bud-scales covered with a glaucous bloom, not conspicuously resinous; bark broken into thick plates; prickly bur about 1 inch in diameter. A. glabra, p. 199.

aa. Terminal bud 1-1-1/2 inches long; bud-scales conspicuously sticky-resinous, glistening; bark broken into thin plates; prickly bur about 2 inches in diameter. A. hippocastanum, p. 197.

1. Winter twig, × 3/4. 2. Leaf, × 1/6. 3. Leaflet, × 1/2. 4. Flower, × 1. 5. Fruit, × 1/2.]

+SAPINDACEAE+

+Horse-chestnut+

Aesculus hippocastanum L.

HABIT.--A handsome tree, with a height of 40-60 feet and a trunk diameter of 1-2 feet, forming a broad, conical crown. The regularly occurring branches ascend from the trunk at first, gradually bend downwards as they lengthen, and end in a thick, upturning spray.