Flora of North America species comparison

Varieties 6 (6 in the flora).

Crataegus pruinosa extends from Arkansas to Wisconsin, through the southern Great Lakes to southern New England, and, in the south, mainly in the Appalachians to northern Georgia.

In the north of its range, Crataegus pruinosa is mainly a shrub of open successional habitats but in the south may commonly be a taller tree of open or thin woodlands.

Many hawthorns have a little waxy bloom on their pomes; it is particularly prominent on Crataegus pruinosa and C. cognata compared to others. Some authors include in C. pruinosa their white-anthered counterparts, here assigned to C. cognata. Whereas C. pruinosa characteristically has entire or subentire sepal margins, some forms in the southwest of the range of the species (for example, C. calliantha Sargent, C. seducta Sargent) may have glandular-serrate sepal margins. They may represent introgression with C. coccinioides. The varieties of C. pruinosa are weakly differentiated from each other, most of them on leaf shape and size characters. The more widespread varieties constitute a range of morphotypes held together by common traits. Crataegus gaudens Sargent is a strikingly distinct form from Pennsylvania that has more or less elliptic leaves with lobes absent; it is clearly related to C. pruinosa. Note that 159. Crataegus ×coleae, a Michigan endemic, will key out here if its laterally scarred pyrenes are missed.

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

Crataegus atrovirens is known from the northern Okanagan, where it is locally common to abundant. One of its most notable characteristics are the unusually large glands on the leaf teeth. It also has smallish flowers for its series. Of species known to date from this region, C. shuswapensis is the one most likely to be confused with C. atrovirens. The mature fruit and the growth habit of C. shuswapensis are similar, but that species has leaves more sharply lobed, glabrous inflorescences, sometimes 15–18 stamens per flower, redder fruit in the fourth week of August, much smaller, less prominent fruiting sepals, whose margins, rather than being serrato-laciniate, are minutely glandular. Crataegus atrovirens also has similarities to C. okanaganensis; it is easily differentiated in the field by the usually much longer thorns, smaller flowers with pink anthers, and much darker fruit in late August. Compared to C. orbicularis, the fruit of C. atrovirens is also conspicuously larger; it is soft and ripe in the fourth week of August when the former is hard but not ripe. The erect, multi-trunked habit is also somewhat distinctive. It is a dull hawthorn, somber in appearance, contrasting markedly with more colorful congeners such as C. okanaganensis.

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