Crataegus chrysocarpa var. subrotundifolia
J. Bot. Res. Inst. Texas 3: 240. 2009.
Shrubs, 20–30 dm. Leaves: blade ovate to rhombic-obovate, base ± cuneate, sinuses: max LII 15–20%, lobe apex acute, veins 3–5 per side, abaxial surface glabrous, adaxial appressed-pubescent young, glabrescent or becoming short-scabrous. Inflorescences: branches thin-pilose. Flowers 15–20 mm diam.; hypanthium glabrous; stamens 10, anthers cream or ivory. Pomes red, suborbicular, 8–10 mm diam., pubescent or glabrous.
Phenology: Flowering May–Jun; fruiting Sep–Oct.
Elevation: 0–400 m
Alta., Ont., Que., Sask., Mass., Mich., N.Y., Vt., Wis.
Nearly all Cypress Hills (Alberta and Saskatchewan) specimens of Crataegus chrysocarpa match the characteristics of var. subrotundifolia, but they are evidently different from the eastern form representing the type.
Variety subrotundifolia is a weakly differentiated variety originally held to be restricted to the southern section of the eastern part of the range of Crataegus chrysocarpa, where it is locally common. In plants from this area, the leaves are more coriaceous and a darker green, and the fruit is a deeper, richer red than those of sympatric var. chrysocarpa.