Flora of North America species comparison

Varieties 2 (2 in the flora).

Crataegus berberifolia is widespread from Texas to Missouri, Florida, and Virginia; it is particularly abundant in Louisiana.

Crataegus berberifolia is little differentiated from some forms of C. crus-galli, except in indumentum; it has relatively small and less variably shaped leaves. Its distribution is quite different. Intermediates with hairy leaves and glabrous inflorescences or nearly glabrous leaves and hairy inflorescences may represent hybrids with C. crus-galli (where they might be reached in the key). Such a situation is found in C. araioclada. Abrasion of the adaxial leaf pubescence may occur, rendering identification more difficult with fruiting material. Crataegus berberifolia has a plethora of yellow and orange-fruited forms, particularly from southern Louisiana. Crataegus fera and C. tersa are red-fruited, C. crocina yellow. The fruit color in the type is unknown; E. J. Palmer (in specimen annotation) called it yellow-orange. A form with exceptionally white-tomentose leaves near Copenhagen, Louisiana, is probably this species. Crataegus regalis var. paradoxa (Sargent) E. J. Palmer, from Missouri and adjacent Kansas and Arkansas, is probably a hybrid between the deeply serrated 'regalis' leaf form of C. crus-galli and a form of C. berberifolia. Two common forms of C. berberifolia occur, treated here as varieties: var. engelmannii with ten pink anthers and var. berberifolia with 20 cream anthers. Forms with 20 pink or ten cream anthers also occur sporadically.

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

Crataegus laurentiana was considered a sporadic entity of the northeast and Wisconsin until the recent discovery of a large population in Minnesota.

Hybrid origin for Crataegus laurentiana between a ser. Macracanthae species and C. chrysocarpa in the broad sense, or C. jonesiae, is supported by intermediacy and sympatry of the suspected parents. Chrysocarpoid characteristics include leaf shape and glandular petioles; macracanthoid traits include late anthesis, pink anthers, and variably eroded pyrene sides.

Specimens from Newfoundland and Quebec are var. laurentiana and are characterized by larger but proportionately narrow leaves, thicker and paler twigs, and pink, normal-sized (1 mm) anthers. They may be distinguished from the partly sympatric var. brunetiana by the smaller and proportionately broader leaves of the latter, and cream anthers, more like Crataegus chrysocarpa. In both forms, the leaves abaxially have conspicuously appressed-pilose veins. A Maine variant is atypically arborescent.

The rare var. dissimilifolia Kruschke from northern Wisconsin has white-cream anthers but larger and more nearly isodiametric, shallowly incised leaves. Similar, also rare, plants from southern Manitoba have pink anthers. Stature and leaf size and shape in both of these place them outside the range of C. chrysocarpa; perhaps C. submollis is a parent.

Unnamed populations from a large area in northeastern Minnesota are the most biologically interesting. They are self-perpetuating and, compared to other forms, have more slender twigs that are generally very dark in their second year, like Crataegus macracantha, smaller leaves, somewhat impressed leaf venation, small (0.6 mm), pink anthers, and ellipsoid fruits.

Crataegus fernaldii is a rare form from Maine and Quebec with lax, elongated, extremely villous corymbs, large flowers (20 mm diam.), pink anthers, and large, pear-shaped fruits gracefully drooping in wide clusters on their long stems.

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