Amelanchier interior
Amelanchier laevis
amélanchier de l'intérieur, inland serviceberry, Wiegand's shadbush
Allegheny serviceberry, amélanchier glabre, smooth serviceberry, smooth shadbush
not fully unfolded;
petiole 10–30 mm;
blade broadly ovate to elliptic, 30–70 × 20–50 mm, base rounded to subcordate, each margin with 3–15 teeth on proximal 1/2 and (2–)4 or 5(–7) teeth in distalmost cm, largest teeth less than 1 mm, apex short acuminate to apiculate, abaxial surface glabrous or sparsely hairy by flowering, surfaces glabrous later.
less than half-unfolded;
petiole (7–)15–26(–36) mm;
blade elliptic to ovate to oblong or obovate, (32–)48–75(–100) × (19–)29–42(–60) mm, base subcordate to rounded, each margin with (0–)10–23(–38) teeth on proximal 1/2 and (1–)5–9(–13) teeth in distalmost cm, largest teeth less than 1 mm, apex acute to acuminate, abaxial surface glabrous (or sparsely hairy) by flowering, surfaces glabrous later.
4–12-flowered, 30–75 mm.
(4–)7–11(–14)-flowered, (25–)43–65(–85) mm.
1 or 2 subtended by a leaf, proximalmost 10–45 mm.
0 or 1(or 2) subtended by a leaf, proximalmost (7–)15–28(–41) mm.
sepals recurved after flowering, 2–5 mm;
petals obovate, 6–15 × 4–5 mm;
stamens 20;
styles 5, 3–5 mm;
ovary apex densely (moderately) hairy (or glabrous).
sepals spreading to recurved after flowering, (1.9–)2.8–4(–5.3) mm;
petals linear-oblong, (8–)12.5–17.3(–22.5) × (2.9–)3.9–5.7(–7.5) mm;
stamens (14–)19–21(–24);
styles (4 or)5(or 6), (2.5–)3.3–4.4(–5.3) mm;
ovary apex glabrous (or sparsely hairy).
purple-black, 6–8 mm diam. 2n = 4x.
dark purple, 8–15 mm diam. 2n = 2x, 4x.
Amelanchier interior
Amelanchier laevis
Amelanchier interior is distinguished by its capacity to grow into a tree to ten meters and by having sparsely hairy young leaves that are often reddish and densely hairy ovary apices. E. L. Nielsen (1939) differentiated A. interior and A. wiegandii on the basis of leaves being carinate in A. wiegandii as opposed to flat in A. interior, and leaf sinuses rounded versus acute. G. N. Jones (1946) considered those differences to be slight, and he included A. wiegandii in A. interior. The authors follow Jones, but retain the common name Wiegand’s shadbush to commemorate Wiegand’s early insights about the taxonomy of Amelanchier. M. L. Fernald (1950) considered A. wiegandii as suggesting a small-leaved A. laevis but with shorter buds, fewer teeth, fewer veins, and summit of ovary heavily tomentose. P. Landry (1975) thought A. wiegandii to be the hybrid of A. arborea and A. sanguinea, and E. G. Voss (1972–1996, vol. 2) reasoned that A. interior is a hybrid swarm involving A. laevis (or sometimes A. arborea) and plants of the A. spicata and/or A. sanguinea complex. A hybrid origin of A. interior from A. laevis and A. sanguinea is reasonable given that stem height, the number of leaf teeth, and petal length are more or less intermediate between those two species. DNA sequences from ITS region indicate that A. interior (A. wiegandii) is a possible later-generation hybrid involving a member of the western North American ITS clade (which also includes A. humilis and A. sanguinea of eastern North America) and some eastern North American taxon (C. S. Campbell et al. 1997). Multiple hybrid origins, possibly from different species, may explain the variability of A. interior. Amelanchier interior has unusually large ranges of lengths for proximal pedicels, sepals, and petals. The leaves of A. wiegandii were described by Nielsen as bronze at flowering; Jones described the leaves of A. interior as green when young. The authors assume that A. interior as they interpret it is polymorphic for the color of young leaves.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Amelanchier laevis is common through much of its range and readily identified by its typically arborescent habit, leaves that are reddish and glabrous by flowering, and relatively long inflorescences, pedicels, and petals. Southeastern United States populations tend to be restricted to high elevations. The relationship to its closest relative, A. arborea, is discussed under the latter.
Amelanchier laevis frequently hybridizes with congeners, including A. arborea, A. bartramiana, A. canadensis, A. humilis, A. interior, A. sanguinea, and A. spicata (M. L. Fernald 1950; L. Cinq-Mars 1971). J. E. Cruise (1964) documented hybrid swarms between A. laevis and both A. arborea and A. canadensis in New Jersey. The hybrid with A. bartramiana can usually be found when these two species grow together (J. E. Weber and C. S. Campbell 1989). The hybrid with A. arborea, A. ×grandiflora Rehder, is used ornamentally.
A. C. Dibble et al. (1998) concluded that Amelanchier laevis is possibly one of the parents of A. "rubra,” an entity that is morphologically distinct. This entity is a tetraploid shrub with stems to 3.5 m and usually colonial, leaves that are reddish and glabrous at flowering, and petals that are often faintly reddish and slightly twisted. Ovary apices are mostly sparsely hairy, but may also be densely hairy or glabrous. Quantitative analysis places A. “rubra” between the cluster of A. laevis plus A. intermedia on the one hand and A. nantucketensis or A. spicata on the other (Dibble et al.). It is possible that this entity could be a hybrid with one of these arborescent species (A. laevis and A. intermedia) plus one of the shrub species (A. nantucketensis and A. spicata). The authors have located populations of A. “rubra” on Mount Desert Island and eastward for about 120 km along the Maine coast. The authors have observed plants that appear to be F1s of this entity and later-generation hybrids with A. bartramiana as one of the parents.
Amelanchier laevis has been documented to be self-compatible and to produce seeds asexually (C. S. Campbell et al. 1985; A. C. Dibble et al. 1998).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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