Zanthoxylum americanum Mill.
Family: Rutaceae
common pricky-ash,  more...
[Zanthoxylum americana Mill.]
Zanthoxylum americanum image
Shrub, sometimes a small tree to 8 m tall Leaves: alternate, stalked, pinnately compound, 10 - 30 cm long, with five to eleven leaflets. Flowers: either male or female, found on separate plants (dioecious), borne in small clusters on previous year's growth, tiny, yellowish green. Fruit: a fleshy capsule, 4 - 6 mm in diameter, green to reddish brown, spherical, pitted, splitting along one side to reveal one or two small, black, oily seeds. Bark: gray to brown with light patches, smooth, developing shallow grooves with age. Twigs: gray to brown, smooth, with two 6 mm flattened prickles at each node. Buds: 4 - 6 mm long, rounded, red, wooly. Leaflets: dull green above, paler beneath, 2 - 7.5 cm long, 1 - 3.8 cm wide, egg-shaped, non-toothed or finely toothed with yellow glands between teeth, slightly wrinkled above, hairy-veined beneath. Odor: released from most plant parts when crushed.

Similar species: Zanthoxylum americanum can be distinguished from other Chicago Region species by its aromatic plant parts, twigs with two flattened prickles at each node, pinnately compound leaves with five to eleven leaflets, and reddish brown spherical capsules that split along one side to reveal one or two black seeds.

Flowering: mid April to early June

Habitat and ecology: Common on slopes in open or grazed woods and along the edges of woods, where it forms thickets.

Occurence in the Chicago region: native

Notes: This species was used by Native Americans to treat toothaches, colic, gonorrhea, rheumatism, fevers, sore throats, and ulcers. Bees collect nectar from the flowers, while birds and small mammals eat the fruit.

Etymology: Zanthoxylum comes from the Greek words xanthos, meaning yellow, and xylon, meaning wood, referring to the yellow heartwood. Americanum means "from America."

Author: The Morton Arboretum

Tall shrub, or rarely a small tree to 8 m, with prickly stems, paired pseudostipular prickles, and strongly aromatic foliage; lfls 5-11, oblong to elliptic or ovate, pubescent beneath at least when young; fls in sessile, umbel-like, precocious axillary clusters on branches of the previous year; sep none; pet yellow-green, fringed at the tip; ovaries 3-5; follicles stipitate, ellipsoid, 5 mm, the surface pitted; 2n=68, 136. Moist woods and thickets; s. Que. to e. N.D., s. to S.C., Ga., and Okla., but only irregularly e. of O. and nw. N.Y.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.