This "Japanese walnut" is widely planted in North America, especially the "heartnut" cultivar which has meats that can be cracked out whole. Escapes have been reported from some northeastern states, including W.Va. (K). Plants are resistant to the canker that has afflicted cinerea, which is sometimes confused. Hybrids of these two species are vigorous and some introgression has been documented across the range of cinerea (Hoban et al. 2009, Zhao et al. 2011, Parks et al. 2014). Distinction of ailantifolia from cinerea can be difficult, especially without fruits. Both species have pale greyish- to whitish-plated bark but the plates of ailantifolia tend to be narrower and less distinct in their paleness as contrasted with fissures, which tend to be shallower and brownish or pinkish in ailantifolia (versus distinctly darker grey in cinerea). Ross-Davis et al. (2009; see also Farlee et al., 2009) reported significant differences in the following characters but did not provide some dimensions: buds shorter and with wider shape (lower L/W); leaf scars narrower (L/W ca. 0.45 versus 0.6) and more notched; lenticels larger (ca. 2.6 mm long versus 0.9 mm), often elongated longitudinally (versus mosly round or often elongated transversly), and less dense (averaging ca. 25 per cm2 versus 40). Male catkins tend to be longer (ca. 10-20 cm versus 6-14 cm). Fruits are produced in clusters of 3-5 are more or less spherical in their main bodies (versus ovoid to cylindric), but with a more abruptly pointed apex; surfaces are densely glandular pubescent, as in cinerea. Cleaned nut surfaces are smooth (versus complexly ridged), which is the most obvious difference.