1. Xanthóxylum Americànum, Mill. (Northern Prickly-Ash. Toothache-Tree.) Leaves and flowers in sessile, axillary, umbellate clusters; leaflets 5 to 9, ovate-oblong, downy when young. Flowers appear before the leaves. Shrub, scarcely at all tree-like, with bark, leaves, and pods very pungent and aromatic. Common north, and sometimes cultivated.
X. Clàva Hércules.
2. Xanthóxylum Clàva Hércules, L. (Southern Prickly-Ash.) Leaflets 7 to 17, ovate to ovate-oblong, oblique at base, shining above. Flowers appear after the leaves. A small tree with very sharp prickles. Sandy coast of Virginia and southward; occasionally cultivated in the north.
Genus 13. PTÈLEA.
Shrub with compound leaves of three leaflets, greenish-white flowers in terminal cymes, and 2-seeded fruit with a broad-winged margin, somewhat like the Elm, only larger.
P. trifoliàta.
Ptèlea trifoliàta, L. (Hop-Tree. Shrubby Trefoil.) Leaflets ovate, pointed, downy when young. Flowers with a disagreeable odor; fruit bitter, somewhat like hops. A tall shrub, often, when cultivated, trimmed into a tree-like form. Wild, in rocky places, in southern New York and southward.
Genus 14. PHELLODÉNDRON.