Observations by conboy

From Rhoads' and Block's "The Plants of Pennsylvania" 2nd edition:
A. leaves convolute in bud, unlobed; branchlets not spine-tipped, anthers yellow.
C. leaves pubescent or villous beneath.
D. hypanthium and pedicels glabrous to villous ---> Malus prunifolia

Chinese crabapple (M. prunifolia) - young branches pubescent; young leaves pubescent beneath but becoming glabrescent; flowers white; calyx glabrous to villous; fruits yellow or red, 2.5 cm in diameter, with persistent calyx; cultivated and rarely escaped, parks, waste ground, and railroad ballast, scattered throughout. Flowers in May, Fruit throughout August and October.