This is widely scattered in eastern North America, but concentrated in the midwest from Ohio and Mich. to Mo. and Minn. It becomes uncommon to rare in more southeastern states, where replaced by the infamous Z. clava-herculis L. Zanthoxylum species are among the few woody plants of temperate regions that combine both thorniness and browsing-repellant chemistry; see also Maclura pomifera. The genus Zanthoxylum is well known for its powerful chemistry with culinary, medicinal or toxic properties; compounds include diverse alkaloids, amides, furanocoumarins and lignans (Bafi-Yeboa et al. 2005, Negi et al. 2011). The numbing effect in human taste is attributed to the amide "sanshool", which is similar to "capsaicin" of chili peppers; fruits of americanum can probably be processed into a spice, but initial trials with just a few fruits have led to painful experiences. In Ky. americanum is widely scattered but locally common at relatively few localities, especially on base-rich soil in thorny scrub around old pastures. Its distribution in Ky. and Tenn. is somewhat similar to the original concentrations of Juniperus virginiana, as documented by Barton (1919) and others. It is unusually abundant near the J.K. Smith power plant in CLAR. And on ridges above Slate Creek near Howards Mill in MONT, stems are up to 4 m tall and 10 cm dbh. Further north, the species reportedly reaches 10 m in height and 15 cm in dbh (Cr, F; Benjamin et al. 2005).