Flora of North America species comparison

Crataegus iracunda ranges from Louisiana to South Carolina and Georgia, and to Virginia, but only at low altitudes. Nearly all records of C. iracunda north of the listed distribution are referable to C. macrosperma or to various species in ser. Populneae.

The distinguishing features of Crataegus iracunda are most evident when it is in flower. The species can be construed as a smaller, more southern, allopatric relative of C. macrosperma distinguished by smaller leaves (particularly at anthesis), more slender thorns, and harder, drier pomes. Its distribution is almost wholly to the south of or in Appalachia, at lower elevations than C. macrosperma. The nearest records of C. macrosperma to the Louisiana populations of C. iracunda are from the Arkansas Ozarks.

Crataegus iracunda has been confused with C. gattingeri (ser. Pruinosae) but is readily distinguished in flower by adaxial leaf pubescence, stamen number, and by lacking the usually attenuate terminal leaf lobes of the latter. However, in fruit, unless the filament bases can be counted, one is left with the less reliable feature of the terminal lobe shape. Confusion with the larger-leaved C. populnea (ser. Populneae) is perhaps possible, but the two species are essentially allopatric and their leaves differ markedly in size and texture.

Earlier attempts to segregate varieties based on leaf size are not taken up here but may have merit as the relatively numerous Louisiana (Crataegus drymophila) form has much smaller leaves than North Carolina specimens.

Variety brumalis (Ashe) Kruschke (Crataegus brumalis Ashe) with syntype material from near Pittsburgh, Pennsylvania, is a different entity. Compared to C. iracunda, it has larger and differently shaped (often more or less truncate-based) leaves, proportionately larger at anthesis, and adaxially subglabrous, conspicuously glandular petioles, and larger flowers. This taxon (as a variety of C. iracunda) is primarily responsible for the northwards extension of the range of the latter species. In fact, north of the Mason-Dixon line, most of the specimens attributed to C. brumalis seen by the author appear to be forms of C. macrosperma.

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

Varieties 5 (5 in the flora).

Crataegus mollis is common and widespread west of the Appalachians from eastern South Dakota to extreme southwestern Ontario, to southern Texas and central Alabama. It is rare in the southeastern part of its range. Sporadic records to the east of this are misidentifications or recent introductions.

Crataegus mollis has 20, or, in one unusual form, 10, cream anthers and is distinguished from the superficially similar 10-stamen C. submollis by lack of pedicel glandularity and stamen number and from pink-anthered taxa of restricted range such as C. texana varieties by anther color. Whether C. mollis is truly distinct from the C. texana complex will require biosystematic work. Crataegus mollis is less glandular than the allopatric C. submollis, from which it differs in further ways (see 52. C. submollis). Crataegus canadensis, from Quebec, but with glandular petioles, could key out here and is treated as a form of C. submollis.

Crataegus mollis is variable in leaf shape and size; other characters are more constant. Northern plants are more floriferous, and their trunk bark is more exfoliating than southern ones, which have a more rough-corrugated bark. The leaves are usually shortest and proportionately widest in Texas. Larger and proportionately narrower leaves are found northeastward. The most superficially distinct form is var. incisifolia, with acute lobes and deep sinuses. The lobing varies from very small to absent in var. dumetosa and C. invisa Sargent. Crataegus meridionalis from Alabama and Mississippi is somewhat similar to var. dumetosa but has longer, elliptic to narrowly ovate, sharply serrate, rather coriaceous leaves.

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