R. Califòrnicus.
3. Rhámnus Califòrnicus, Esch. (California Buckthorn.) Leaves evergreen, oval-oblong to elliptical, 1 to 4 in. long, rather obtuse, sometimes acute, generally rounded at base, serrulate or entire. Fruit blackish purple, with thin pulp, ¼ in., 2- to 3-seeded. A spreading shrub, 5 to 18 ft. high, without thorns; from California.
Genus 21. HOVÈNIA.
Leaves alternate, deciduous, simple, oblique at base. Fruit an obscurely 3-lobed, 3-celled, 3-seeded pod in dichotomous clusters, both axillary and terminal.
H. dúlcis
Hovènia dúlcis, Thunb. Leaves long-petioled, more or less ovate to cordate, serrate, palmately 3-ribbed, much darker on the upper surface; both sides slightly roughened with scattered hairs. Fruit sweet, edible, in clusters in the axils of the leaves; seeds lens-shaped, with a ridge on the inner side. Flowers white; in July. A large, broad-topped tree, introduced from Japan. Hardy at Washington, but dies to the ground in the Arnold Arboretum, Massachusetts.
Genus 22. ZÌZYPHUS.
Leaves simple, alternate, deciduous, 3-ribbed. Flowers axillary, 5-petaled. Fruit fleshy, drupe-like, containing a 1- to 2-celled nut.
