The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

alder-leaf shadbush, amélanchier à feuilles d'aulne, saskatoon, saskatoon berry, saskatoon serviceberry, service berry, western serviceberry

Photo is of parent taxon

dwarf service berry, dwarf shadbush

Habit Shrubs, 1–12 m. Stems 1–50, solitary or colonial. Shrubs, 1–2(–4) m. Stems 1–50, solitary or in colonies.
Leaves

mostly unfolded;

petiole (3–)6.8–19.1(–28) mm;

blade usually elliptic to oval to suborbiculate, sometimes quadrangular, (14–)24–47(–67) × (7–)17–36(–55) mm, base usually subcordate to truncate, sometimes ± tapering or ± cuneate, each margin with 0–3(–9) teeth on proximal 1/2 and (0–)3–5(–8) teeth in distalmost cm, largest teeth more than 1 mm, apex rounded to truncate or occasionally acute or mucronate, abaxial surface sparsely to densely hairy (or glabrous) by flowering, sparsely to moderately hairy (or glabrous) later, adaxial glabrous or sparsely (moderately) hairy later.

petiole (7–)11.9–19.1(–27) mm;

blade orbiculate to oval, (14–)26–37(–50) × (18–)23–36(–43) mm, base usually cordate to truncate, sometimes ± cuneate, apex rounded or subtruncate, surfaces glabrous.

Inflorescences

(4–)6–11(–16)-flowered, (8–)14–43(–62) mm.

(6 or)7–9(–12)-flowered, (24–)29–40(–47) mm.

Pedicels

(0 or)1 or 2(or 3) subtended by a leaf, proximalmost (2–)3–20(–29) mm.

proximalmost (8–)10–20(–27) mm.

Flowers

sepals erect to recurved after flowering, (1.4–)2.2–4(–4.9) mm;

petals oblanceolate to oval or obovate to elliptic, (5.7–)9.5–14(–18.8) × (2.2–)3.3–5.2(–6.6) mm;

stamens (10–)15–21(–22);

styles (3 or)4 or 5(or 6), (1.3–)2–2.9(–3.9) mm;

ovary apex moderately to densely hairy (or glabrous).

sepals (2.7–)3.2–4(–4.5) mm;

petals obovate to elliptic, (9–)10.9–11.5(–12.6) × (3–)3.8–5.2(–5.9) mm;

ovary apex glabrous (or sparsely hairy with a ring of hairs at base of styles).

Pomes

black or purple, 8–15 mm diam.

8–9 mm diam. 2n = 4x.

Amelanchier alnifolia

Amelanchier alnifolia var. pumila

Phenology Flowering May–Jun; fruiting Jul–Sep.
Habitat Mountain slopes
Elevation 2000–3400 m (6600–11200 ft)
Distribution
from FNA
AK; AZ; CA; CO; IA; ID; KS; MN; MT; ND; NE; NM; NV; OR; SD; TX; UT; WA; WY; AB; BC; MB; NT; ON; SK; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; UT; WY
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

Amelanchier alnifolia is widespread and polymorphic, and its taxonomic and geographic limits have been viewed differently. L. Cinq-Mars (1971) considered this species to range eastward to the Gaspé Peninsula. Disagreements about the boundary between A. alnifolia and A. humilis are evident in herbarium specimen annotations. The distinctness of the varieties of A. alnifolia has also been questioned. G. N. Jones (1946) treated the three varieties recognized here as distinct species and noted that the leaves of var. alnifolia and var. semiintegrifolia (A. florida) are virtually indistinguishable, and, although petal lengths of the two do not overlap, occasional larger-flowered var. alnifolia and occasional smaller-flowered var. semiintegrifolia occur, so the petal length distinction is not an absolute one. Geographically these two varieties are largely separate, with var. alnifolia occurring in the Great Plains and Rocky Mountains and var. semiintegrifolia on the Pacific slopes of mountains from Alaska to northern California.

Amelanchier alnifolia is thought to hybridize with Sorbus scopulina (x\Amelasorbus jackii Rehder).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The most distinctive features of var. pumila are that its leaves, pedicels, sepals, and ovary apices are glabrous (with the exception of a few hairs on emerging leaves and a ring of hairs around the base of the styles in some plants), and its leaf teeth are relatively long and sharp-pointed. This variety appears to be restricted to higher elevations.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Ovary apices glabrous (or sparsely hairy); shrubs 1–2(–4) m.
var. pumila
1. Ovary apices moderately to densely hairy (or glabrous); shrubs or trees, 1–12 m
→ 2
2. Inflorescences (8–)26–43(–62) mm; proximalmost pedicels (5–)8–16(–29) mm.
var. alnifolia
2. Inflorescences (8–)14–26(–35) mm; proximalmost pedicels (2 or)3–8(–13) mm.
var. semiintegrifolia
Source FNA vol. 9, p. 651. FNA vol. 9, p. 652.
Parent taxa Rosaceae > subfam. Amygdaloideae > tribe Maleae > Amelanchier Rosaceae > subfam. Amygdaloideae > tribe Maleae > Amelanchier > Amelanchier alnifolia
Sibling taxa
A. amabilis, A. arborea, A. bartramiana, A. canadensis, A. cusickii, A. fernaldii, A. gaspensis, A. humilis, A. interior, A. intermedia, A. laevis, A. nantucketensis, A. nitens, A. pallida, A. sanguinea, A. spicata, A. utahensis
A. alnifolia var. alnifolia, A. alnifolia var. semiintegrifolia
Subordinate taxa
A. alnifolia var. alnifolia, A. alnifolia var. pumila, A. alnifolia var. semiintegrifolia
Synonyms Aronia alnifolia A. canadensis var. pumila
Name authority (Nuttall) Nuttall ex M. Roemer: Fam. Nat. Syn. Monogr. 3: 147. (1847) (Torrey & A. Gray) C. K. Schneider: Ill. Handb. Laubholzk. 1: 739. (1906)
Web links