Crataegus acutifolia Sargent; C. albanthera Sargent; C. arborea Beadle; C. barrettiana Sargent; C. calophylla Sargent; C. candens Sargent; C. cherokeenis Sargent; C. consueta Sargent; C. crus-galli var. capillata Sargent; C. crus-galli var. exigua (Sargent) Eggleston; C. crus-galli var. leptophylla (Sargent) E. J. Palmer; C. crus-galli var. macra (Beadle) E. J. Palmer; C. crus-galli var. oblongata Sargent; C. crus-galli var. pachyphylla (Sargent) E. J. Palmer; C. hamata Sargent; C. hannibalensis E. J. Palmer; C. infera Sargent; C. leptophylla Sargent; C. ludoviciensis Sargent; C. monosperma Sargent; C. pachyphylla Sargent; C. paradoxa Sargent; C. parkiae Sargent; C. permera Sargent; C. phaneroneura Sargent; C. polyclada Sargent; C. pyracanthoides Beadle var. arborea (Beadle) E. J. Palmer; C. regalis Beadle; C. rubrifolia Sargent; C. rudis Sargent; C. severa Sargent; C. strongylophylla Sargent; C. tantula Sargent; C. tardiflora Sargent; C. tenax Ashe; C. tenuispina Sargent; C. truncata Sargent

Leaf blades: relatively wide (1.5:1–2.5:1).

Flowering Apr–Jun; fruiting Sep–Nov. Brush, sandy soil, dense shade; 10–300 m; Ont., Que.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Minn., Miss., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., W.Va., Wis.

Attempts to divide this complex into taxa based on stamen number and anther color have been unsatisfactory. Crataegus arborea (cream anthers) and C. tenax (pink anthers) appear to be the earliest names for 20-stamen forms, which E. J. Palmer and others wrongly called C. fontanesiana (Spach) Steudel [= C. calpodendron (see J. B. Phipps 1987)]. Crataegus crus-galli in the strict sense would be restricted to the 10-stamen, white-anthered form. Such a circumscription is not followed here because the collective variation in all 10- and 20-stamen forms, not only in stamen number and anther color, is much greater than the differences between them. T. A. Dickinson (1983) showed that in southern Ontario, clear phenological and morphological differences occur between 10- and 20-stamen forms.

Rare forms with three to five styles, for example, Crataegus leptophylla, may be hybrids with C. reverchonii var. reverchonii. The widely recognized var. capillata Sargent with inflorescence branches sparsely villous is here synonymized as that is all that distinguishes it.