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 avium in classical schools, it must once more be said that cherry trees (at least the bird cherry) existed in Italy before Lucullus, and that the famous gourmet did not need to go far to seek the species with the sour or bitter fruit. De Candolle suggests that what Lucullus brought back was a particular cultivar of "Prunus avium" from the Caucasus. The origin of cultivars of "P. avium" is still an open question. Modern cultivated cherries differ from wild ones in having larger fruit, 2–3 cm diameter. The trees are often grown on dwarfing rootstocks to keep them smaller for