Common pricky-ash

Description

Zanthoxylum americanum, the common prickly-ash, common pricklyash, common prickly ash or northern prickly-ash (also sometimes called toothache tree, yellow wood, or suterberry), is an aromatic shrub or small tree native to central and eastern portions of the United States and Canada. It is the northernmost New World species in the citrus family, Rutaceae, and is the type species in its genus, which includes sichuan pepper. It can grow to 10 meters (33 ft) tall with a diameter at breast height (DBH) of 15 cm (5.9 in). It produces membranous leaflets and axillary flower clusters. The wood is not commercially valuable, but oil extracts from the bark have been used in traditional and alternative medicine, and have been studied for antifungal and cytotoxic properties. The genus name is sometimes spelled Xanthoxylum. The plant has pinnately compound leaves with 5–11 membranous leaflets. It has axillary flower and fruit clusters. The buds are hairy. The dark green leaves are bitter-aromatic, with crenate margins. The stalked follicles are green and then turn red through deep blue through black. Flowers are dioecious, with yellow-green petals. Flowers appear as umbrella-like clusters from 2–12 in small terminal to axillary umbellate clusters. They are imperfect with pedicels 2–4 m long; there are 4–5 petals, elliptic to ovate-oblong 1.6–1.9 mm long and have green with reddish hairs near the tips; stamens 5; ovary with 2–5 carpels. The fruit is a follicle, with 2 seeds per carpel. Rare in the South, it is more common in the northern United States. In the United States, it occurs in Alabama, Arkansas, Connecticut, Delaware, the District of Columbia, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Virginia, Vermont, Wisconsin and West Virginia; the species also occurs in Ontario and Quebec in Canada. The species is listed as Endangered in Florida, Maryland, and New Hampshire; and as Special Concern in Tennessee. Butterflies that use Zanthoxylum americanum as a larval food source include the Thoas swallowtail (Papilio thoas), giant swallowtail (P. cresphontes), and spicebush swallowtail (P. troilus).