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 ursina It is usually present in too small a quantity to do any harm but any very bitter seed or fruit should not be eaten. Consumption of small quantities of hydrogen cyanide stimulates respiration and improves digestion. Excessive consumption of the toxin can cause respiratory failure and death. "Prunus ursina" fuits better in full sun but is still successful in partial shade. The tree will form suckers if its shallow roots are damaged. Among the pests that affect the "prunus" genus is honey fungus. the seed requires 2–3 months cold stratification in order to germinate. Prunus ursina Prunus ursina (bear's plum,