Trees of the Northern United States by Apgar
Shrubs or trees with mostly odd pinnate
Shrubs and trees, rarely herbs, in most cases with transparent-dotted, heavy-scented foliage. A rather large order in warm climates.
GENUS =12. XANTHOXYLUM.=
Shrubs or trees with mostly odd-pinnate, alternate leaves. The stem and often the leaflets prickly; flowers small, greenish or whitish; fruit dry, thick pods, with 1 to 2 seeds.
[Illustration: X. Americanum.]
1. =Xanthoxylum Americanum=, 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.
[Illustration: X. Clava Hercules.]
2. =Xanthoxylum Clava Hercules=, 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. PTELEA.=
Shrub with compound leaves of three leaflets, greenish-white flowers in terminal cymes, and 2-seeded
[Illustration: P. trifoliata.]
=Ptelea trifoliata=, 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. PHELLODENDRON.=
Leaves opposite, odd-pinnate. Flowers dioecious; so only a portion of the trees bear the small, odoriferous, 5-seeded, drupe-like fruit.
[Illustration: P. Amurense.]
=Phellodendron Amurense.= (CHINESE CORK-TREE.) Leaves opposite, odd-pinnate, 1 1/2 to 3 ft. long; leaflets 9 to many, lanceolate, sharply serrate, long-acuminate. Flowers inconspicuous, dioecious, in loose-spreading clusters at the ends of the branches. The pistillate flowers form small, black, pea-shaped fruit, in loose, grape-like clusters, thickly covered with glands containing a bitter, aromatic oil, and remaining on the tree in winter. Medium-sized tree (20 to 40 ft.), with Ailanthus-like leaves which turn bright red in autumn, and remain long on the tree. Hardy as far north as central Massachusetts.
ORDER =X. MELIACEAE.= (MELIA FAMILY.)
Tropical trees, including the Mahogany; represented in the south by the following:
GENUS =15. MELIA.=