Amelanchier sanguinea

Red-twigged shadbush, amélanchier sanguin

Description
Shrubs or small trees. Stems 1–20, 1– 7 m, somewhat clumped; twigs glabrous at flowering. Leaves conduplicate in bud; expanded as well as unfolded or nearly so, green (purple), abaxially densely hairy by flowering; petioles 12–30 mm; blades abaxially green, elliptic-oblong to suborbiculate or obovate, 2.5–7 x 2–5.5 cm, firm , bases rounded to subcordate, margins dentate to or nearly to base with 3–5(–6) teeth per cm, lateral veins 12–15 pairs, remaining distinct to the margin and not anastomosing, apices rounded and mucronate to subacute, surfaces glabrous or glabrate . Inflorescences 4–10-flowered, soon arching or drooping, 4–8 cm, only proximalmost 1–2 pedicels subtended by leaf. Pedicels hairy, proximalmost 1–3 cm. Flowers: hypanthia saucer-shaped, 3.5–7.5 mm diam.; sepals recurving or spreading after flowering , 3.5–5 mm, adaxially hairy; petals white, linear to narrowly spatulate, 11–18 x 3–5.7 mm, not andropetalous; stamens 20; styles 5; ovary summit rounded, densely hairy. Pomes dark purple or almost black, 5–8 mm diam., sweet. 2n = 34, 51, 68.


Flowering/Fruiting
Flowering May–Jun; fruiting Jul–Aug.

Habitat
Margins of woods, river ledges, shorelines, rocky slopes, crevices of open rock faces and cliffs, noncalcareous to slightly calcareous sites; 0–1000 m

Range
N.B., Ont., Que., Sask.; Ala., Iowa, Ky., Ill., Maine, Mass., Md., Mich., Minn., N.H., N.Y., N.C., Ohio, Pa., Tenn., Vt., Va., W.Va., Wis.

Discussion
(see Systematics page for references cited)
We follow G. N. Jones’s (1946) and E. G. Voss’s (1985) inclusion of Amelanchier huronensis in A. sanguinea. Amelanchier huronensis was considered to differ from A. sanguinea in having longer proximalmost pedicels, sepals, and petals, and a wider hypanthium, but overlap occurs in the ranges of all characters except hypanthium width. Moreover, we have seen A. sanguinea far from the range of A. huronensis (southern Ontario, Michigan, Minnesota, and Wisconsin) with petals as long as the longest reported for A. huronensis.

Amelanchier sanguinea and A. amabilis stand out among eastern North American Amelanchier in their coarsely dentate leaves with veins that clearly extend to the margin. Amelanchier sanguinea has shorter petals and narrower hypanthia than A. amabilis. These two species share with A. humilis saucer-shaped instead of campanulate hypanthia, as in other eastern North American members of the genus. Amelanchier humilis differs from A. sanguinea and A. amabilis in having less prominent leaf teeth, erect inflorescences, and shorter petals.

Amelanchier sanguinea, A. amabilis, and, to a lesser extent, A. humilis resemble western North American Amelanchier in leaf teeth and veins.

G. N. Jones (1946) broadened the interpretation of Amelanchier sanguinea to include A. amabilis, E. G. Voss (1985) also included A. gaspensis, and P. Landry (1975) added A. humilis and all western North American species. Landry’s very broad circumscription of A. sanguinea is justified by the coarsely toothed leaves (2–5 teeth per cm), and by strong support from ITS DNA sequences (C. S. Campbell et al. 1997) for a clade of all sampled western North American taxa plus A. humilis and A. sanguinea.

Amelanchier sanguinea flowers 10 to 14 days after A. arborea and A. laevis, according to K. M. Wiegand (1912), and at the same time as A. amabilis. Hybrids between A. sanguinea and A. bartramiana, A. canadensis, A. laevis, and A. spicata have been reported (M. L. Fernald 1950; P. Landry 1975). We have observed A. sanguinea flowering with A. amabilis but no putative hybrids.