Flora of North America species comparison

Varieties 2 (2 in the flora).

Because of variation in the degree of hairiness on branches and leaves, thickness of leaves, leaf shape, sizes of racemes and flowers, and colors of fruits, Prunus virginiana has been split into forms, varieties, and segregate species. When viewed on a continental scale, most of the key characteristics used to separate these taxa intergrade enough so as to be useless.

The most useful distinction is between chokecherries found east of the Rocky Mountains and those found from the mountains westward. They differ in leaf shape and raceme size; the variation is imperfectly correlated. The eastern plants generally have their larger leaves obovate with lengths less than two times widths, racemes typically less than 7 cm, and petals to 4 mm. Plants of the Rockies and west have longer racemes and larger petals, and generally their larger leaves are elliptic to oblanceolate leaves with lengths two or more times widths. Distinctions between the eastern and western varieties are least obvious from Montana to eastern Washington north into British Columbia, where the varietal ranges overlap. Plants of the High Plains show intergradation between those of the Rockies and those of the East. The taxonomic solution provided here is a single species of chokecherry in North America with an eastern and a western variety that overlap in range along a line from northeastern New Mexico to southwestern British Columbia.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Varieties 4 (3 in the flora).

Variety capuli (Cavanilles) Hatusima [subsp. capuli (Cavanilles) McVaugh] is known from Mexico (Chiapas, Jalisco, Distrito Federal, México, Puebla), Central America, and South America (Argentina, Bolivia, Colombia, Ecuador, Peru, Venezuela). It is distinguished from var. serotina by lanceolate to ovate-lanceolate leaves with decurrent bases (versus elliptic to obovate with obtuse to cuneate bases) and a long (to 2 cm), thin (1 mm) petiole; inflorescences tend to be subtended by 3 or 4 leaves [versus 2 (or 3), reduced in size], with a rachis relatively longer (greater than 15 cm), thicker, and flexuous compared to other varieties, and shorter pedicels (3–5 mm versus 5–10 mm, in var. serotina).

The characters given in the key usually allow easy separation of Prunus serotina from P. virginiana; some specimens from Arizona and southern Utah are difficult to determine. In that area, it is not uncommon for the sepals of P. virginiana flowers to lack the glandular teeth that are common elsewhere and thus mimic those of P. serotina. Variety rufula has thicker leaves that are also much shinier on both surfaces than those of P. virginiana and shorter petioles (2–15 mm versus 4–27 mm).

Compounding the confusion with chokecherry is a nomenclatural conundrum in which the epithet virginiana has been used for both chokecherry (the next species) and for black cherry (this species). The status of the two names Prunus serotina and P. virginiana was discussed by K. N. Gandhi et al. (2009), who proposed the conservation of both names.

Of our native Prunus species only P. serotina grows large enough to produce commercial lumber, which is highly prized for its fine grain and rich, warm, reddish brown color.

(Discussion copyrighted by Flora of North America; reprinted with permission.)