Forestry

Tree and Shrub Identification

Prunus Key

Because the identification of the members of this genus is difficult, two summer keys, as well as a winter key are included here.

 

Summer Key (A)

1 Flowers axillary (solitary, umbellate or corymbed) from scaly buds, which remain on the branches over the winter months, expanding with or before the leaves 2
  Flowers terminal (in elongate racemes) at end of new leafy branches 4
2 (1) Ovary and fruit covered by a bloom or pubescence; fruit with two opposite longitudinal shallow lines or grooves with more or less fibrous flesh and somewhat flattened stone; pedicels short and stout 3
  Ovary and fruit glabrous and without bloom; fruit red, globose or nearly so, without longitudinal furrows, having a subglobose stone; flowers in umbels or corymbs, white; leaves membranaceous, gradually acute or acuminate, glabrous, finely serrate with the young teeth gland tipped (pin cherry) Prunus pensylvanica
3 (2) Teeth of leaves not glandular, sharply acute; calyx lobes mostly glandless; leaves abruptly long acuminate; petioles mostly without terminal glands; fruit red or yellow (American plum) Prunus americana
  Teeth of young leaves glandular or gland tipped, rounded, crenate or depressed (if deciduous the glands leave callous remnants); calyx lobes glandular on margin; leaves abruptly acuminate, their teeth relatively coarse and spreading; petioles usually with 2 apical glands; fruit light red, orange red or yellow (Canada plum) Prunus nigra
4 (1) Leaves ovate to obovate, thin, with sharp teeth; calyx limb deciduous, its lobes broad and blunt; fruit deep red to red purple (common chokecherry) Prunus virginiana
  Leaves lance oblong to oblong ovate, taper pointed or acute, firm, with blunt callous teeth; calyx limb persistent in fruit, its narrow lobes acute; fruit dark red, becoming purple black (black cherry) Prunus serotina

 

Summer Key (B)

1 Leaves lanceolate, oblong lanceolate or elliptical 2
  Leaves broader, ovate, obovate or oblong ovate 3
2 (1) Leaves smooth and waxy on lower surface, pubescent along midrib on under side, with blunt callous teeth; flowers terminal, in racemes (black cherry) Prunus serotina
  Leaves wrinkled and veiny on under side, with finely serrate, gland-tipped margins; flowers axillary, in corymbs (pin cherry) Prunus pensylvanica
3 (1) Leaves sharply serrate 4
  Leaves crenate serrate with apex acuminate; stem or branches often thorny; terminal bud absent; flowers axillary, 3 to several (Canada plum) Prunus nigra
4 (3) Leaves with acuminate apex; stem or branches often thorny; terminal buds absent; flowers axillary (American plum) Prunus americana
  Leaves with obtuse or acute apex; stem or branches not thorny; terminal bud present; flowers in terminal racemes (common chokecherry) Prunus virginiana

 

Winter Key

1 Terminal buds present 2
  Terminal buds absent; buds glabrous, ovoid fusiform; thorns usually present 4
2 (1) Buds clustered at the ends of slender red twigs and short spurs; twigs glossy (pin cherry) Prunus pensylvanica
  Buds not clustered at the ends of both twigs and spurs (clusters of buds present only at the end of spurs, or at the end of slender twigs when spurs are absent) 3
3 (2) Buds about 6 mm long; bud scales rounded at apex, their margins light gray, covered part brown; twigs stout, light brown, dull: bark of trunk smooth (common chokecherry) Prunus virginiana
  Buds about 4 mm long; bud scales blunt or pointed at apex, exposed part nearly uniform reddish brown, covered part green or reddish; twigs slender or medium, reddish brown, glossy; bark rough and scaly on old trunks (black cherry) Prunus serotina
4 (1) Buds black or gray, usually over 4 mm long (Canada plum) Prunus nigra
  Buds red brown, usually 4 mm long (American plum) Prunus americana
Last Revised: Monday July 30 2007