P. communis: shrub; leaves ovate or oblong; flowers small white, nearly sessile, solitary or in pairs, appearing before the leaves; drupes covered with a bluish bloom. - Blackthorn. - Woods and hedges. Fl. April May.
Different forms of this are called: P. spinosa, the Sloe, with spiny branches and small austere globular fruits; P. insititia, the Bullace, less spiny, and with larger less austere fruits; P. domestica, the Plum, without spines, and with still larger oblong fruit.
P. Cerasus: shrub or small tree; leaves ovate or ovate-lanceolate; flowers large, white, on long pedicels, 2-3 or more together, appearing before the leaves; drupes without bloom. - Cherry or Gean. - Woods and hedges. Fl. April, May.
There are two forms of this: P. Cerasus, representing the austere Morello cherries, and P. Avium, the sweet cherries of our gardens.
P. Padus: shrub; leaves oval or ovate-lanceolate; flowers small, white, in long drooping racemes; drupes small, without bloom. - Bird Cherry. - Woods and hedges. Fl. May.