5. Álnus cordifòlia, Ten. (Heart-leaved Alder.) Leaves heart-shaped, dark green and shining. Flowers greenish-brown, blooming in March and April, before the leaves expand. A large and very handsome Alder, 15 to 20 ft. high, growing in much dryer soil than the American species. Cultivated from southern Europe. Hardy after it gets a good start, but often winter-killed when young.
Genus 85. CÓRYLUS.
Low trees and large shrubs with simple, alternate, deciduous, doubly serrate, straight-veined leaves. Flowers insignificant, in catkins in early spring. Fruit an ovoid-oblong bony nut, inclosed in a thickish involucre of two leaves with a lacerated frilled border; ripe in autumn.
| * Leafy bracts of fruit forming a bottle-shaped involucre | 2. | |
| * Leafy bracts not bottle-shaped. (A.) | ||
| A. Involucre much longer than the nut | 1. | |
| A. Involucre but little longer than the nut | 3. | |
C. Americàna.
1. Córylus Americàna, Walt. (Wild Hazelnut.) Leaves roundish heart-shaped, pointed, doubly serrate; stipules broad at base, acute, and sometimes cut-toothed; twigs and shoots often hairy. Involucre of the fruit open to the globose nut, the two leaf-like bracts very much cut-toothed at the margin and thick and leathery at the base. Merely a shrub, 5 to 6 ft. high; quite common throughout.
C. rostràta.
2. Córylus rostràta, Ait. (Beaked Hazelnut.) Leaves but little or not at all heart-shaped; stipules linear-lanceolate. The involucre, extending beyond the nut in a bract like a bottle, is covered with stiff, short hairs. Shrub, 4 to 5 ft. high. Wild in the same region as Corylus Americana, but not so abundant.