The leaves of Ailanthus altissima are compound, alternate and large with numerous leaflets--well-developed leaves usually exceed 30 cm in length with 13 or more leaflets. The leaflets are each more than 1 cm broad and the margins are entire, or with a few coarse, blunt teeth near the base.

Ailanthus altissima is not native to North America, but it has been widely planted and tends to escape into disturbed, sunny, mostly urban sites. It is very fast growing, but is generally a small tree with a short lifespan. It is probably more common as an escape than is indicated by the map, but urban weeds are often overlooked by collectors and the large leaves are inconvenient to press for vouchers.