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.)

Crataegus castlegarensis occurs from around the northern Okanagan, British Columbia, to the northern California Coast Ranges, to northwestern Montana, and the Rocky Mountains to northeast of Salt Lake City, Utah. The species occurs also in the Cypress Hills of Alberta and Saskatchewan; it is found in habitats similar to those of C. douglasii and is at least as abundant as that species in a number of parts of its range.

Crataegus castlegarensis is readily recognized by a combination of hairy inflorescence branches, pomes more or less orbicular, crimson or burgundy (with irregular earlier ripening) around the third week of August, soon becoming purple, often when nearby C. douglasii is already black, as well as a tendency to possess thorns on the young twigs branched at the base to become double, triple, or even sometimes quadruple. Such multiple thorns, though sometimes abundant on a bush, are more often few and may require searching for. Inflorescence pubescence, as in other species with this characteristic, may become sparse by fruiting. Crataegus castlegarensis is most similar to C. douglasii; its fruit is usually more orbicular, even oblately so, than is normal in that species, sometimes even with a recessed junction to the pedicel like an apple.

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