Tree to 12 m, not sprouting from the roots; lvs firm, oblong to oblong-obovate, 6-10 cm, abruptly acuminate, broadly rounded at base, coarsely and usually doubly serrate with broad, acuminate, ovate-triangular teeth 1-2 mm, slightly pubescent and somewhat rugose above, permanently soft-pubescent and ±reticulate-veiny beneath; petiole usually with a pair of distal glands; pedicels usually glabrous, 8-20 mm; hypanthium glabrous or sparsely pubescent; sep narrowly oblong, 2-3 mm, pubescent on both sides; pet white, 8-10 mm; fr purplish-red, glaucous, globose or ellipsoid, 2-3 cm long; stone turgid, obovoid to subglobose. Rocky open woods; Mo. and s. Ill. to Ala. and Tex., and n. Mex., with outlying stations to O., Ky. and S.D. Apr. (P. americana var. lanata)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Probably frequent in southwestern Indiana, and infrequent to rare northward. The plums are not easy to identify, hence their collection may be neglected. It is necessary to collect the flowers and mature fruit from the same plant and this task is not as easy at it might seem. I have collected flowers from many a shrub and tree and returned at fruiting time to find that fruit had not developed.