In its typical form, Helianthus occidentalis is distinctive with its relatively few basal leaves and scapiform stems. Still unresolved is the status of H. dowellianus, which may deserve recognition at some level. These plants have the head morphology of H. occidentalis but have multiple pairs of well-developed cauline leaves. Plants with this morphology are found in the southern Appalachian region from Maryland to Georgia. According to C. B. Heiser et al. (1969), these plants may be hybrids of H. occidentalis and H. atrorubens. Natural hybrids of H. occidentalis with H. mollis have been called H. ×cinereus Torrey & A. Gray. Hybrids of H. occidentalis with other species are known.
From Flora of Indiana (1940) by Charles C. Deam
This species is local but not rare in the lake area. It is always found in very sandy soil and usually in moist places such as low depressons in black oak woods, at the bases of the slopes of black oak woods, and sometimes on sandy knolls and ridges. In addition to the area shown on the map it has been reported from Vigo County where it doubtless formerly occurred.