Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
1 Flowers solitary, in fascicles, in umbellate or corymbose inflorescences, or in short racemes (P. mahaleb) of 1-12 flowers.
..2 Fruit glabrous; ovary glabrous or pubescent initially; flowers and fruit pedicellate, the pedicel > 4 mm long (except…)
....3 Stones globose, not 2-edged; sepals hairy or not; inflorescences subtended by leafy bracts arising from the same bud as the flowers (except P. pensylvanica, P. susquehanae, and P. pumila); [cherries, subgenera Cerasus and Lithocerasus]
....3 Stones somewhat to strongly flattened, 2-edged; sepals hairy on the upper surface (except P. domestica, P. insititia, and P. cerasifera); inflorescences without leafy bracts arising from the same bud as the flower; [plums, subgenus Prunus]
..2 Fruit densely velvety or puberulent; ovary densely velvety or puberulent; flowers and fruits sessile or on pedicel 0-2 mm long.
......4 Fruit scarlet-red, 0.8-1.5 cm in diameter; twigs densely tomentose; fruit and ovary glabrous or somewhat pubescent (but not velvety); leaves < 5 (-7) cm long; petals white (pink in bud), < 13 mm long; [subgenus Lithocerasus, section Armeniacocerasus]
......4 Fruit yellow, peach, or orange-colored, > 2 cm in diameter; twigs glabrous; fruit and ovary velvety pubescent; leaves > 5 cm long; petals white or pink, > 11 mm long.
........5 Leaves 8-15 cm long, > 4× as long as wide, falcate; fruit peach-colored, > 5 cm in diameter; [peach; subgenus Amygdalus, section Persica]
........5 Leaves 5-10 cm long, 1-1.5× as long as wide, not falcate; fruit yellow to orange, 3-5 cm in diameter; [apricots; subgenus Prunus, section Armeniaca].
..........6 Twigs reddish-brown; fruits 3-5 cm in diameter, the flesh sweet when ripe