Prunus spinosa the more shrubby habit with stiffer, wider-angled branches of "P. spinosa"; in summer by the relatively narrower leaves of "P. spinosa", more than twice as long as broad; and in autumn by the colour of the fruit skin purplish black in "P. spinosa" and yellow or red in "P. cerasifera". "Prunus spinosa" has a tetraploid (2"n"=4"x"=32) set of chromosomes. The specific name "" is a Latin term indicating the pointed and thornlike spur shoots characteristic of this species. The common name "" is due to the thorny nature of the shrub, and its very dark bark. The word commonly used
Prunus persica × Prunus americana tree is included in the Purdue University book "Fruit Breeding", Volume 1. The hybrid at Broadus, Montana has never fruited as the flowerbuds have all winterkilled. The hybrid has bloomed in Pennsylvania and the blooms are sterile. As of 2013, the hybrid near Broadus is still alive. Prunus persica × Prunus americana Prunus persica" × "Prunus americana is the hybrid between the peach "Prunus persica" (often a nectarine) and the wild American plum "Prunus americana". Hybrids were obtained in the 1940s at the University of Minnesota, and have been used in subsequent breeding, such as in the parentage of a