1. XANTHÓXYLUM, L. Prickly Ash.
Flowers diœcious. Sepals 4 or 5, obsolete in one species. Petals 4 or 5, imbricated in the bud. Stamens 4 or 5 in the sterile flowers, alternate with the petals. Pistils 2–5, separate, but their styles conniving or slightly united. Pods thick and fleshy, 2-valved, 1–2-seeded. Seed-coat crustaceous, black, smooth and shining. Embryo straight, with broad cotyledons.—Shrubs or trees, with mostly pinnate leaves, the stems and often the leafstalks prickly. Flowers small, greenish or whitish. (From ξανθός, yellow, and ξύλον, wood.)
1. X. Americànum, Mill. (Northern Prickly Ash. Toothache-tree.) Leaves and flowers in sessile axillary umbellate clusters; leaflets 2–4 pairs and an odd one, ovate-oblong, downy when young; calyx none; petals 4–5; pistils 3–5, with slender styles; pods short-stalked.—Rocky woods and river-banks; common, especially northward. April, May.—A shrub, with yellowish-green flowers appearing before the leaves. Bark, leaves, and pods very pungent and aromatic.
2. X. Clàva-Hérculis, L. (Southern P.) Glabrous; leaflets 3–8 pairs and an odd one, ovate or ovate-lanceolate, oblique, shining above; flowers in an ample terminal cyme, appearing after the leaves; sepals and petals 5; pistils 2–3, with short styles; pods sessile. (X. Carolinianum, Lam.)—Sandy coast of Virginia, and southward. June.—A small tree with very sharp prickles.
2. PTÈLEA, L. Shrubby Trefoil. Hop-tree.
Flowers polygamous. Sepals 3–5. Petals 3–5, imbricated in the bud. Stamens as many. Ovary 2-celled; style short; stigmas 2. Fruit a 2-celled and 2-seeded samara, winged all round, nearly orbicular.—Shrubs, with 3-foliolate leaves, and greenish-white small flowers in compound terminal cymes. (The Greek name of the Elm, here applied to a genus with similar fruit.)
1. P. trifoliàta, L. Leaflets ovate, pointed, downy when young.—Rocky places, Long Island to Minn., and southward. June.—A tall shrub. Fruit bitter, used as a substitute for hops. Odor of the flowers disagreeable.
Ailánthus glandulòsus, Desf., called Tree of Heaven,—but whose blossoms, especially the staminate ones, are redolent of anything but "airs from heaven,"—is much planted as a shade-tree, especially in towns, and is inclined to spread from seed. It belongs to the order Simarubaceæ, which differs from Rutaceæ in the absence of dots in the leaves. The tree is known by its very long pinnate leaves of many leaflets, and small polygamous greenish flowers in panicles, the female producing 2–5 thin, linear-oblong, veiny samaras. (Adv. from China.)
Order 25. ILICÌNEÆ. (Holly Family.)