Mapping is provisional; these trees may appear intermediate between calleryana and communis, suggesting hybrid origin, but there is no definitive evidence of such crosses (FNA 9). The names P. bretschneideri Rehd. or P. serrulata Redh. have been tentatively applied to naturalized trees that are similar to calleryana but have larger fruit, ca. 1-3 cm in width. These are poorly understood taxa of possible hybrid origin (2n = 34, 51, 68), perhaps involving P. pyrifolia (Burmann f.) Nakai, P. betulifolia Bunge or other species (Flora of China Vol. 9;FNA 9; Vincent 2005, Zheng et al. 2014). Better keys are needed to account for potential variation. Vincent cited the colls. mapped here from BULL and CAMP; the other records come from recent observations of JC. These records all date from after 1990. During recent decades development of edible pears for market in North America has involved the southeast Asian species, pyrifolia, which has globose fruit that lack persistent calyx as in other Asian species. P. pyrifolia may be expected to persist from cultivation and it may be spreading by seed. There are recent records of "pyrifolia" from most states adjacent to Ky. (K, W), but it may be preferable to refer these records to "cf. bretschneideri".or some other name (FNA 9).