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Published In: The Gardeners Dictionary: eighth edition Xanthoxylum no. 2. 1768. (16 Apr 1768) (Gard. Dict. (ed. 8)) Name publication detailView in BotanicusView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 9/8/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native

 

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1. Zanthoxylum americanum Mill. (common prickly ash, northern prickly ash, toothache tree)

Pl. 552 h–j; Map 2566

Plants shrubs or rarely small trees, colonial from rhizomes, dioecious, 0.5–3.0(–8.0) m tall. Stems with usually few, ascending branches, the bark relatively smooth, gray to dark brown with lighter blotches and scattered, small, light-colored, more or less circular lenticels, occasionally becoming longitudinally fissured on old trunks, armed with small, flattened, slightly downward-curved prickles, these mostly subopposite and stipulelike at the nodes, the twigs gray to dark brown, moderately to densely short-hairy when young, becoming glabrous with age. Leaves alternate, short-petiolate, the petiole not jointed at the tip, unwinged. Leaf blades pinnately compound with 5–11(–13) leaflets, these 1–6(–8) cm long (progressively longer from the basal pair), oblong to elliptic, or ovate, the lateral pairs sometimes very slightly oblique, angled or short-tapered to a sessile or minutely stalked base, rounded or more commonly angled to a bluntly or sharply pointed tip, the margins entire or minutely scalloped, the upper surface dark green, sparsely to moderately and minutely hairy along the veins, becoming glabrous with age, the undersurface pale green to light green, moderately pubescent with somewhat longer, fine, somewhat tangled hairs, mostly along the veins and near the margins, becoming nearly glabrous with age. Inflorescences produced before the leaves, axillary, small umbellate clusters, the individual flowers short-stalked (sometimes appearing nearly sessile at flowering, the stalks elongating as the fruits develop). Flowers imperfect. Sepals absent. Petals 4 or 5, 1.5–2.5 mm long, narrowly oblong-obovate, overlapping in bud, yellowish green, with a minutely uneven apical portion and usually a fringe of short, crinkly reddish brown hairs. Stamens in staminate flowers 4 or 5 (absent or reduced to 4 or 5 minute staminodes in pistillate flowers), alternating with the petals, the filaments free, slender, and glabrous, attached outside of a small, often lobed or incomplete nectar disc around the ovary base. Ovaries 2–5 per flower, each short-stalked (reduced to a more or less lobed rudiment in staminate flowers), glabrous, 1-locular with 2 ovules, rounded or short-tapered at the tip, the styles fused above their bases, the stigma minute, with 2–5 lobes. Fruits 2–5 separate follicles per flower, each 4.5–6.0 mm long, ellipsoid to ellipsoid-obovoid, tapered to a short stalk at the base, abruptly tapered to a minute, oblique beak at the tip, the outer surface leathery, pitted, red to dark red or reddish brown, sometimes brownish yellow with a reddish tinge, glabrous or minutely hairy. Seeds 1 or 2 per fruit, 4.0–4.5 mm long, obovoid to nearly globose, sometimes (in 2-seeded follicles) somewhat flattened, the outer surface with faint, coarse facets or pits and finely pebbled, black, shiny. 2n=34. April–May.

Scattered in the state, most abundantly outside the Ozark Division (eastern U.S. west to North Dakota and Oklahoma; Canada). Openings of mesic to dry upland forests, tops of bluffs, savannas, glades, banks of streams and rivers, and margins of ponds, lakes, and sinkhole ponds; also pastures, old fields, old strip mines, and railroads.

Uphof (1922) reported the closely related Z. clava-herculis L. (Hercules club, southern prickly ash) from southeastern Missouri, but no herbarium specimens have been located to substantiate his observations. This species occurs from Virginia to Florida west to Oklahoma and Texas and differs in flowering after the leaves expand and in having leaves with mostly 9–13 leaflets, the lateral ones strongly oblique at their bases, more or less terminal, looser inflorescences, and calyces of 5 sepals.

 


 

 
 
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