This widespread species of northeastern woodlands extends south into Appalachian regions, the Ozarks and other hills in eastern states, mostly on medium acid soils. In Ky. it extends into the Knobs but more western records remain somewhat dubious. Some uncertain records may reflect hybridization with pensilvanicus or related taxa in the Arguti group; see notes under alumnus. R. allegheniensis (sensu lato) differs from the Arguti group in its predominantly glandular (versus largely glandless) inflorescence and primocanes, the glands flattened to cupulate versus rounded (FNA9, W). Also, its terminal leaflets are ovate, cordate or broadly rounded at base, and long attenuate or caudate at apex; those of the Arguti group are ovate to oblong-lanceolate, often more gradually narrowed at base, and usually acuminate at apex (F). R. allegheniensis is more shade tolerant than the Arguti group, but it is still sensitive to browsing by deer. Within woodland, canopy gaps and fires can cause large increases (especially where combined), but only if herbivory is limited (Royo et al. 2010; and pers. comm.).