Shrubs or trees with opposite, evergreen, entire leaves and small flowers. The fruit 3-celled, 6-seeded pods.
B. sempérvirens.
Búxus sempérvirens, L. (Boxwood.) Leaves ovate, smooth, dark green; leaf-stems hairy at edge. This plant is a native of Europe, and in its tree form furnishes the white wood used for wood-engraving.
Var. subfruticosa (dwarf boxwood) grows only a foot or two high, and is extensively used for edgings in gardens. The tree form is more rare in cultivation, and is of slow growth, but forms a round-topped tree.
Order XXXVI. URTICÀCEÆ. (Nettle Family.)
A large order of herbs, shrubs and trees, mainly tropical.
Genus 74. ÚLMUS.
Tall umbrella-shaped trees with watery juice and alternate, 2-ranked, simple, deciduous, obliquely ovate to obliquely heart-shaped, strongly straight-veined, serrate leaves, harsh to the touch, often rough. Flowers insignificant, appearing before the leaves. Fruit a flattened, round-winged samara; ripe in the spring and dropping early from the trees. Bark rough with longitudinal ridges.
| * Leaves very rough on the upper side. (A.) | |||
| A. Leaves 4 to 8 in. long; buds rusty-downy; inner bark very mucilaginous | 1. | ||
| A. Leaves smaller; buds not downy; cultivated. (B.) | |||
| B. Wide-spreading tree; twigs drooping; fruit slightly notched | 2. | ||
| B. Tree rather pyramidal; twigs not usually drooping; fruit deeply notched | 3. | ||
| * Leaves not very rough on the upper side. (C.) | |||
| C. Buds and branchlets pubescent; twigs often with corky ridges | 4. | ||
| C. Buds and branchlets free from hairs, or very nearly so. (D.) | |||
| D. Twigs with corky wings | 5. | ||
| D. Twigs often with corky ridges; cultivated | 2, 3. | ||
| D. Branchlets never corky | 6. | ||