64f.8. Crataegus Linnaeus (sect. Coccineae) ser. Coccineae (Loudon) Rehder, Man. Cult. Trees ed. 2. 362. 1940.
Crataegus sect. Coccineae Loudon, Arbor. Frutic. Brit. 2: 816. 1838; Crataegus [unranked] Lobulatae Sargent
Shrubs or trees, (40–)70–120 dm, main trunk dominant. Stems: trunk bark older buff, newly exposed orange, exfoliating in fibrous plates, freshly exposed bark orange-brown (not recorded for some species); ˂branches spreading; twigs ± straight˃, new growth glabrous or hairy, 1-year old golden to pale tan, older light gray; thorns on twigs few to numerous, straight to recurved, 2-years old dark blackish brown, shiny, ± stout, sometimes slender, 2–6 cm. Leaves: petiole length 30–40% blade, glabrate to hairy, eglandular or at least some glandular; blade ˂bright green˃, broadly elliptic to elliptic-ovate or ± ovate to deltate-ovate, (4–)5–8(–10) cm, thin, base cuneate to subtruncate, rarely slightly cordate, lobes 4 or 5 per side, sinuses shallow to ± deep, lobe apex acute, sometimes acuminate, margins serrate, ˂teeth numerous˃, venation craspedodromous, veins 5–7(or 8) per side, apex acute to subacute, abaxial surface usually glabrous, veins pubescent, adaxial appressed-pubescent. Inflorescences 8–15-flowered, convex panicles; branches usually pubescent, rarely glabrous or tomentose; bracteoles caducous, linear, membranous, margins sessile- or short-stipitate-glandular. Flowers 16–22 mm diam.; hypanthium usually pubescent, sometimes glabrous; sepals narrowly triangular, much shorter than petals, margins glandular-serrate; stamens 5–8, rarely 10 or 20, anthers pink to rose-purple, sometimes crimson; styles (3 or)4 or 5. Pomes bright to deep red, suborbicular to oblong or ± ovoid, sometimes ellipsoid to broadly pyriform, 10–14 mm tall, glabrous or villous; flesh ± mealy, mellow; sepals variably persistent, ± spreading or erose, ˂non-accrescent˃; pyrenes (3 or)4 or 5.
Species 3 (3 in the flora): c, e North America; introduced in Europe.
As treated here, ser. Coccineae has three species, largely following J. A. Macklin (2001). They occur from extreme southeastern Minnesota and Illinois eastward through the southern Great Lakes to southern New England and south down the Appalachians to North Carolina.
Members of ser. Coccineae are easily confused with those of ser. Molles; Crataegus pennsylvanica from that series keys out in the first couplet. A detailed comparison is presented with ser. Molles. The best distinctions concern bracteoles (hairier and more herbaceous in ser. Molles) and indumentum (more likely tomentose in ser. Molles). Rare putative hybrids with various species are recorded, including ser. Dilatatae (C. putnamiana Sargent), ser. Punctatae (C. mansfieldensis Sargent), ser. Tenuifoliae (C. merita Sargent), ser. Populneae (C. xanthophylla Sargent); see also section on interserial hybrids.
Confusion about the name of the series was caused by C. S. Sargent (1901), who suggested that Crataegus coccinea was the correct name for C. chrysocarpa (at that time called C. rotundifolia). Consequently, until his correction in 1909, the group Coccineae by Sargent was approximately the current ser. Rotundifoliae. His original view was followed by various other workers, which added to the confusion.
Members of ser. Coccineae are shrubs or trees of forest edges and gaps as well as successional sites on agricultural land. They can be exceptionally attractive throughout the growing season and are among the most dramatic fall-fruiting shrubs. Anthesis is early midseason relative to sympatric species.
Selected References Macklin, J. A. 2001. Systematics of Crataegus Series Coccineae (Rosaceae). Ph.D. thesis. University of Western Ontario. Macklin, J. A. and J. B. Phipps. 2002. Sargent's names in Crataegus series Coccineae (Rosaceae). Harvard Pap. Bot. 7: 25–35. Macklin, J. A. and J. B. Phipps. 2006. Studies in Crataegus ser. Coccineae. I. Canad. J. Bot. 84: 70–86. Sargent, C. S. 1901. Notes on Crataegus in the Champlain Valley. Rhodora 3: 19–31.