A study of the botanical characters of the many Triflora plums under cultivation fails to show any lines of cleavage whereby the species can be divided. Of plums commonly grown in America it is not very closely related to any unless it be _Prunus simonii_. There are several plums from eastern and central Asia with which we are not at all familiar in America that may show relationship with _Prunus triflora_, chief of which are _Prunus ichangana_ Schneider,[94] _Prunus thibetica_ Franchet[95] and _Prunus bokhariensis_ Royle,[96] the last a cultivated plum from northern India. These, in herbarium specimens, have some characters reminding one of _Prunus triflora_, others of _Prunus domestica_ and still others, of _Prunus cerasifera_. The Triflora, or Japanese,[97] plums are now cultivated in all parts of the world where plums are grown; yet outside of Japan and China they have been grown for their fruit less than half a century. Despite the fact that these plums have been grown in Asia for several centuries the wild form is not known. Indeed, there are doubts in the minds of some as to whether it constitutes a distinct species, Maximowicz, an authority on the flora of Japan, among others, holding that it is but a form of _Prunus domestica_. Roxburgh in naming it gave but little definite information in regard to the species, but the herbarium specimens of his in the Kew Herbarium are readily identified as identical with our Japanese plums.[98] The confusion between _Prunus triflora_ and _Prunus domestica_ seems needless, as the points of difference between these two species are several and very distinct and constant, the resemblances between _Prunus triflora_ and some of the American species being much closer. So, too, the effort, sometimes made, to make more than one species out of _Prunus triflora_ is straining a point, for though the types under cultivation vary considerably yet the variations are not greater than between varieties of other species of the genus Prunus.