Vascular Plants of North Carolina
Account for Common Prickly-ash - Zanthoxylum americanum   P. Mill.
Members of Zanthoxylum with account distribution info or public map:
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Section 6 » Order Sapindales » Family Rutaceae
AuthorP. Mill.
DistributionCollected from 3 counties in the southern mountains -- Buncombe, Jackson, and Transylvania -- all, oddly enough, by 3 people in July 1953! This seems a bit suspicious, especially as all collections are at a single herbarium at Western Carolina University. Additionally, the species was not included in NC by RAB (1968), Weakley (2018), or other flora (including the NCNHP). However, these are listed in SERNEC. Nonetheless, the locations of several of these -- if not all -- might not be natural.

Ranges across southeastern Canada and the northeastern and north-central U.S., south mainly to VA, KY, MO, and OK. Scattered records in all eastern states but MS.
AbundanceSeemingly always very rare, and now historical -- all collections in SERNEC were made in 1953. The website editors suggest a State Rank of SH, though it could easily be considered as perhaps not native in NC and with a rank of SE?. The editors also suggest it be at least on the Watch List as W4 [rare and possibly or perhaps not native].
HabitatRequires high pH soil, generally in rocky situations. Favors dry to mesic forests in rocky places, generally over limestone, less so over other calcareous or mafic rocks.
PhenologyFlowers before leaves emerge in March-April, and fruits in July-August.
IdentificationThis is a deciduous shrub growing to 6-9 feet tall (occasionally to 20 feet), and often as wide or wider. Strong and wide thorns are present along the stem/branches. It has alternate compound leaves, with 7-13 leaflets (several pairs with one at the apex); the rachis has small thorns as well. Each leaflet is elliptic to lanceolate, sessile, with a pointed tip. It has small flowers in leaf axils, in clusters, in early spring; in late summer, there are numerous reddish follicles, with shiny blackish seeds. It should be difficult to mis-identify this very rare shrub in NC, owing to its thorny look and often 9 elliptical (and pointed) leaflets, especially with thin spines along the leaf blade. The biggest issue is judging natural-ness of sites of occurrence, as there is no guarantee this species deserves a place on the NC list of native species.
Taxonomic CommentsNone

Other Common Name(s)Northern Prickly-ash, Toothache-tree (used also for a few other species)
State Rank[SH]
Global RankG5
State Status[W4]
US Status
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