This is widespread in central and eastern North America, but generally uncommon to absent in regions with infertile acid soils. In the original woodlands of Ky., occidentalis was common in the Bluegrass region, but much less frequent elsewhere (Barton 1919, Campbell 1989). Barton's data shows a strong concentration in FAYE and adjacent counties. During the period of Virginian settlement (1770-1800), surveyors of the Bluegrass region often named this somewhat novel species "hoopwood" (or perhaps "hoop ash" or even "bettywood") instead of "hackberry." It has now increased and spread in many regions. Apparent variation, and possible rare hybridization with laevigata and tenuifolia needs further study. Juvenile, shaded or sprouting leaves of those other species (especially C. laevigata var. smallii) may be hard to distinguish from occidentalis. According to A. Whittemore (Y), occidentalis differs in its larger leaf blades on fertile shoots, mostly 7-12 cm long (versus 3-9 cm), with 23-40 teeth on longer side (versus 0-15) and 5-8 secondary veins (versus 3-5), the secondary areoles 5-9 times as long as wide (versus 2.5-7 times); fruits are 8-10 mm long (versus 5-8 mm) and usually brownish to blue-black (versus often orange to red, at least when immature). Based on earlier treatments (especially GC), most trees in Ky. may be referable to var. canina (Raf.) Sarg., with relatively broad, partly cordate leaves. But some colls. with relatively tough scabrous leaves, including many from the Bluegrass region, fit the more western var. crassifolia (Lam.) Gray. A few scattered colls. fit the more southern var. occidentalis, with relatively broad but less cordate leaves, and with shorter, more reddish fruit (suggesting transition to laevigata). See also notes under tenuifolia regarding possible intergradation with that species. Bark, leaves and fruits of Celtis have general interest for mammalian nutrition, with complex chemistry (e.g. El-Alfy et al. 2011). C. occidentalis, like other species in the genus, provides relatively palatable nutritious food for herbivorous mammals, and it can be reduced by intense continuous browsing (e.g. Atwood 1941, Apsley et al. 1984, Swihart & Picone 1991, Crisler & Russell 2010). It has little chemical defence but much resprouting ability. The curious corky ridges on bark (especially well developed in more northern regions) may be a deterrent to browsing animals; equines often chew on hackberry trunks in the winter. Fruits and seeds are often eaten and cached by small mammals, in addition to being dispersed by birds. Casual observations suggest that seeds of commonly associated Prunus serotina (with cyanogenic chemistry) are cached much less.