Amelanchier interior
Amelanchier arborea
amélanchier de l'intérieur, inland serviceberry, Wiegand's shadbush
Allegheny serviceberry, common serviceberry, downy servicberry, downy serviceberry, downy 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 (5.5–)12–20.6(–29.2) mm;
blade ovate to obovate, (30–)47–68(–93) × (16–)26–40(–56) cm, base cordate to rounded, each margin with (0–)11–21(–30) teeth on proximal 1/2 and (3–)5–9(–13) teeth in distalmost cm, largest teeth less than 1 mm, apex acute to acuminate, abaxial surface densely (moderately) hairy by flowering, glabrous or sparsely to moderately hairy later, adaxial glabrous or sparsely (moderately) hairy later.
4–12-flowered, 30–75 mm.
(3–)6–12(–15)-flowered, (19–)30–55(–79) mm.
1 or 2 subtended by a leaf, proximalmost 10–45 mm.
0 or 1 subtended by a leaf, proximalmost (5–)10–20(–32) 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 soon reflexed after flowering, (1.6–)2.3–3.7(–5.3) mm;
petals linear to oblong, (8–)10–15(–19) × (2–)3.1–5(–6.8) mm;
stamens (16–)20(–21);
styles (3–)5(or 6), (2.1–)3.2–4.2(–5.5) mm;
ovary apex glabrous or sparsely (densely) hairy.
purple-black, 6–8 mm diam. 2n = 4x.
maroon-purple, 6–10 mm diam. 2n = 2x, 4x.
Amelanchier interior
Amelanchier arborea
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 arborea is distinctive for its arborescent habit, generally precocious flowering, leaf margins each with (3–)5–9(–13) teeth on distal cm, densely hairy abaxial surface of leaf blades, and strongly reflexed sepals at flowering. Leaves typically have subcordate to strongly cordate bases, acuminate apices, and margins sometimes finely double serrate.
The name Amelanchier canadensis was applied by many botanists to A. arborea and A. laevis until M. L. Fernald (1941) clarified the issue; this usage appears in some older manuals. McKay transferred A. laevis to subspecific status under A. arborea, and the two species are generally considered to be closely related. Allozyme data show that, with one exception, populations of each are more closely related to a nearby population of the other than they are to conspecific populations (R. D. Overath and J. L. Hamrick 1998). At flowering, A. arborea and A. laevis can be distinguished by leaf color, which is typically reddish green or reddish brown in A. laevis and green to greenish white in A. arborea. In addition, the leaves of A. laevis are at least half-expanded and unfolding as well as glabrous (or sparsely hairy) by flowering, and its sepals are spreading to reflexed.
Amelanchier arborea exhibits considerable variation; infraspecific taxa have been named. Variety alabamensis differs in its densely hairy ovary apices. Variation in ovary summit indument in A. arborea does not appear to be associated with any other taxonomically informative variation; individuals with varying amounts of ovary indument occur sporadically in populations; this does not appear ecologically significant. The authors conclude that this variety does not warrant taxonomic recognition; they have observed groups of populations that differ in the number of flowers per inflorescence, color of the expanding leaves, size of the teeth, and other features.
Amelanchier arborea usually flowers a week or more before sympatric congeners. The species has been reported (M. L. Fernald 1950) to hybridize with A. bartramiana, A. canadensis, A. humilis, and A. laevis. The authors have collected putative hybrids with A. amabilis in New York and have observed putative hybrids between A. arborea and other eastern North American species of Amelanchier. Hybrid swarms in New Jersey between this species and A. laevis but not A. canadensis have been reported (J. E. Cruise 1964).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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