Fam. Nat. Syn. Monogr.3: 147. 1847
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).
|1||Ovary apices glabrous (or sparsely hairy); shrubs 1–2(–4) m.||Amelanchier alnifolia 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.||Amelanchier alnifolia var. alnifolia|
|2||Inflorescences (8–)14–26(–35) mm; proximalmost pedicels (2 or)3–8(–13) mm.||Amelanchier alnifolia var. semiintegrifolia|
|Author||Christopher S. Campbell +, Michael B. Burgess +, Kevin R. Cushman +, Eric T. Doucette +, Alison C. Dibble + and Christopher T. Frye +|
|Basionym||Aronia alnifolia +|
|Common name||Alder-leaved shadbush +, saskatoon +, saskatoon berry + and amélanchier à feuilles d'aulne +|
|Illustrator||Marjorie C. Leggitt +|
|Taxon name||Amelanchier alnifolia +|
|Taxon parent||Amelanchier +|
|Taxon rank||species +|
|Volume||Volume 9 +|