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 uniflora is widespread in the southeastern United States from Long Island (New York) to eastern Texas; it is most abundant in the coastal plain and lower piedmont. A disjunction in the Mississippi embayment between trans-Mississippian and cis-Mississipian populations mirrors a similar pattern in C. spathulata (J. B. Phipps 1998).

Crataegus uniflora is usually easy to identify because of its small size, leaves small and coriaceous with lobes absent, numerous straight, fine thorns, inflorescences uniflorous or few-flowered, sepals glandular-pectinate and equal to or longer than the petals, anthers white to cream, and pomes yellowish to ruddy. Possible confusion with some members of ser. Lacrimatae is treated under the series discussion. Sterile plants might be confused with small, sterile ones of C. berberifolia (ser. Crus-galli) except for the smaller number of lateral veins on the leaves. An interesting feature of C. uniflora is the occasional deep lobing of extension-shoot leaves, even narrow ones, with veins to sinuses.

Crataegus uniflora is somewhat variable in plant size, leaf shape, number of flowers to an inflorescence (though commonly one), and anther color (usually ivory to cream). The typical form, which is common, has 1- or 2-flowered inflorescences, and is usually a small shrub with more or less spatulate to narrowly obovate leaves. Some particularly dwarf forms of this, on laterite soil in Georgia, have been observed with over 100 flowers when less than 3 dm.

Forms of Crataegus uniflora with 3–6-flowered inflorescences are also common and are represented by C. parvifolia and C. trianthophora. These are connected to the typical uniflorous kind by numerous intermediates and may be distinguished from the related C. brittonii by their smaller and narrower leaves with lobes absent.

Three anomalous variants, very similar or identical to Crataegus uniflora except for possessing small, more or less unlobed but glandular-serrate sepals, are known. These are: C. croomiana Sargent from northern Florida, C. bisulcata Ashe from North Carolina, and C. grossiserrata Ashe from Florida. The first, also best known, is further distinguished by pink anthers, the second by broader leaves, and the third by often orbiculate (unusual for ser. Parvifoliae) extension-shoot leaves with a tendency to deep lobing sometimes with veins to sinuses, and particularly strong and sharp leaf teeth. All suggest hybrid origin with ser. Lacrimatae.

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