Flora of North America species comparison

Crataegus douglasii occurs from southern and western British Columbia to the panhandle of Alaska and ranges to northern California and the Rocky Mountains of Idaho, Montana, and southwestern Alberta. Disjunct populations occur farther east in the Cypress Hills (Alberta and Saskatchewan), the Montana montane islands, and around the northern Great Lakes. In western North America, C. douglasii is found mainly near water in drier areas; in more mesic regions, it may occur in open woodlands. In the Great Lakes area, it mainly occurs in old pastures and on fencerows.

Crataegus douglasii is distinguished from C. gaylussacia by having ten stamens and is rather variable in leaf shape and size. The species is distinguished from C. okennonii by the latter usually being taller and typically more erect as well as having a usually straight, single trunk, shorter thorns, ampulliform-orbicular fruit, and often purplish crimson fall foliage. Crataegus castlegarensis is the most similar species, and beyond possessing relatively few to many multiple thorns, it is distinguished from C. douglasii by its hairy hypanthia, pedicels, and, often, fruit, which is orbicular, plump, crimson to purple in late August, ripening to deep purple (sometimes black) at a time when sympatric C. douglasii is fully black.

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

Crataegus punctata is a common northeastern North American hawthorn, ranging across the northeast quarter of the United States and adjacent Canada to New Brunswick, to North Carolina and Tennessee, occurring mainly above 1000 m in the southern Appalachians. South of New Jersey, it is not found near the coast. The species may occur in nearly pure populations of up to several thousand individuals. The best growth is in sunny sites near streams.

Crataegus punctata is recognized among sympatric species by its matte green leaves (unlike the somewhat similar C. crus-galli) with impressed veins, tabulate branching when grown in the open, usually burgundy fruits with pale dots; the whitish or ashy gray twigs present a distinctive feature in winter (J. B. Phipps et al. 2003, plate 55), responsible for the common name white haw. The similar C. collina, with an allopatric distribution and much earlier flowering season, is often confused with it but is readily differentiated (see key and discussion for that species). Extension-shoot leaves of C. punctata may be very deeply incised with veins to the sinuses, a characteristic not found in C. collina.

Some forms of Crataegus punctata bear scarlet or yellow (var. aurea Aiton) fruit. Hairier forms, especially hairier leaves, have been named var. canescens Britton; very small-leaved forms have been called var. microphylla Sargent. Nearly glabrous forms, all with somewhat glossy foliage, less coarse leaf toothing than C. punctata, and ten stamens, occur sporadically and have been named C. grandis Ashe and var. pausiaca (Ashe) E. J. Palmer. They are probably hybrids with C. crus-galli, as is the similar C. ×disperma, treated under interserial hybrids. The very rare C. ×puberis Sargent is perhaps a hybrid with C. macrosperma, C. ×kellermanii Sargent a hybrid with C. pruinosa, and C. ×neobaxteri Sargent a hybrid with a species of ser. Rotundifoliae.

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