34. Crataegus reverchonii Sargent, Trees & Shrubs. 1: 55, plate 28. 1903.
[(as reverchoni)]
Reverchon hawthorn
Shrubs, 10–30(–80) dm. Stems: twigs: new growth glabrous, 1-year old dark gray; thorns on twigs slightly reflexed, 2-years old blackish, usually stout, 3–6 cm. Leaves: petiole 2–5 mm, length 7–11% blade, glabrous, eglandular; blade (on extension shoots) ± orbiculate to broadly elliptic, (on short shoots) ± orbiculate to broadly oblong-elliptic, 2–6 cm, very coriaceous, base broadly cuneate, lobes 0, margins serrulate in distal 1/2, venation semicamptodromous, veins 5 or 6 per side, apex subacute to obtuse, surfaces sparsely hairy young, glabrescent. Inflorescences 8–15-flowered; branches usually glabrous; bracteoles linear, ˂small˃, margins short-stipitate-glandular. Flowers 8–12 mm diam.; hypanthium glabrous, sometimes slightly pilose; sepals 4 mm, margins subentire, abaxially glabrous; stamens 10–15(–20), anthers cream, rose, or red; styles (2 or)3–5. Pomes red to orange-red, suborbicular, 10 mm diam., glabrous; sepals ˂persistent˃, patent or reflexed; pyrenes (1–)3–5.
Varieties 3 (3 in the flora): sc, se United States.
Crataegus reverchonii is differentiated from C. crus-galli by a greater number of styles and pyrenes (except for var. mohrii) and extension-shoot leaves that tend to be suborbiculate. Distinction from a small-leaved form of C. crus-galli from the Edwards Plateau, Texas, needs elucidation. Crataegus stevensiana is sometimes separated out as a variety or species; however, the complex, unresolved variation makes this distinction moot at the moment.
The principal variation within Crataegus reverchonii is between smaller-statured, smaller-leaved, smaller-fruited, more-styled, xeromorphic plants of the southwest (var. reverchonii), and larger-leaved, large-flowered, fewer-styled plants of the mid latitude, eastern United States (var. palmeri). Variety mohrii is intermediate.
