Crataegus [unranked] Molles Sargent, Silva 13: 33. 1902; Crataegus sect. Molles (Sargent) C. K. Schneider

Shrubs or trees, (20–)40–100 dm, main trunk dominant. Stems: trunk bark buff to gray-brown, fibrous, checked into longitudinal plates, freshly exposed bark orange-brown; ˂branches spreading; twigs ± straight˃, new growth pubescent, sometimes glabrescent, 1-year old tan or grayish tan to brown, 2-years old pale gray-brown, older gray; thorns on twigs absent (particularly mature) or few to numerous, ± straight to ± recurved, 2-years old dark brown to black, ± stout, 3–7(–9) cm. Leaves: petiole length (25–)30–50% blade, pubescent to tomentose, sometimes glabrescent, usually eglandular; blade ± elliptic to ± ovate, ± rhombic, or rhombic-ovate, sometimes suborbiculate or ovate-deltate, 4–8(–12) cm, thin to ± firmly chartaceous, base broadly cuneate to subtruncate or rounded, lobes 0 or 1–6 per side (1 or 2 apiculi per side in C. brazoria), sinuses shallow to deep, lobe apex obtuse to very acute, margins usually strongly serrate, venation craspedodromous, veins (3 or)4–7(–9) per side, apex acute to obtuse, abaxial surface hairy to glabrate except on veins, adaxial hairy young. Inflorescences (5–)10–20-flowered, convex panicles, ˂arising subterminally from woody shorts shoots of season˃; branches densely pubescent to tomentose; bracteoles (smaller) caducous, linear, membranous, margins sessile- or stipitate-glandular, (larger) ± persistent, narrowly oblong, ± herbaceous, margins sessile- or stipitate-glandular, abaxially villous. Flowers (14–)18–25 mm diam.; hypanthium ± densely pubescent to tomentose; sepals narrowly triangular, much shorter than petals, margins glandular-laciniate to glandular-serrate, rarely nearly entire; ˂petals white, sometimes pink at late anthesis in C. mollis˃; stamens 5 or 6, 10, or 20, anthers usually ivory or rose, sometimes cream to pale pink or salmon, red, or purple; styles (3–)5. Pomes orange-red, bright or deep red, or bright yellow, usually suborbicular, 8–15(–25) mm diam., hairy (at least base and apex); flesh mealy; sepals ± retained, erect or erect-patent to broadly spreading, rarely incurved, ˂± accrescent˃; pyrenes (3–)5.

Species 6 (6 in the flora): North America; introduced in Europe.

Crataegus mollis and immediate relatives (with 20 stamens except in rare forms of C. mollis) mostly occur from the Great Plains to the Appalachians south to the Gulf Coast; C. pennsylvanica and C. submollis (with ten stamens) range from Wisconsin to New England, to Delaware, and North Carolina (C. pennsylvanica).

As defined here, and following E. J. Palmer (1925) except for excluding Crataegus greggiana, ser. Molles comprises four wide-ranging and two local species.

Plants in ser. Molles comprise relatively large-leaved, large-flowered, rather early flowering hawthorns that are shrubs or trees with stout thorns, relatively large, usually red fruit, glandular-serrate sepals, and plant parts that are usually very hairy, especially when young; similar characteristics are found in ser. Coccineae. Compared to ser. Coccineae, specimens of ser. Molles are usually more hairy, particularly on the abaxial leaf surfaces, in the inflorescences, and in the density and persistence of indumentum. Other distinctions lie in the larger bracteoles in ser. Molles being broader and subherbaceous (versus narrower and membranous in ser. Coccineae) and in the fruiting sepals in ser. Molles being accrescent and tending to be suberect (versus non-accrescent and spreading in ser. Coccineae). The characteristic bracteoles of ser. Molles taxa are very evident in figures for J. B. Phipps (2012). Additionally, at least in their region of sympatry, the filament lengths of ser. Molles are shorter relative to length (50–60% versus 70–90%). Because of difficulties in measuring these delicate organs, this information is not used in the key.

Members of ser. Molles may also be confused with the somewhat similar ser. Punctatae but differ in their much more tomentose indumentum, usually larger and relatively wider leaves, wider and more persistent bracteoles, and, in most species, more deeply dissected sepals. Crataegus phippsii, a purple-fruited species of ser. Purpureofructus from the Pacific Northwest, is also similar in aspect and can be confused in flower. The rare local species C. ×dispessa, C. ×kelloggii, and C. ×latebrosa, previously assigned to the series, represent hybrids or hybrid derivatives with species of other series and key out in the second, fifth, and eleventh couplets, respectively; they possess more membranous, less persistent bracteoles, are usually not tomentose in the same way, and have thinner leaves, and are treated under interserial hybrids.

SELECTED REFERENCE Phipps, J. B. 2012. Critical taxa in series Molles (Crataegus, Rosaceae): Typifications, new combinations, and taxonomic review. Phytoneuron 2012–78: 1–23.