A shrub of varying habit, often of low growth, but capable of attaining a height of 20 ft or so, stoloniferous; young twigs and leaf-undersides hairy at first, soon glabrous. Leaves mostly oval to broadly oblong or even orbicular, rounded to truncate at the apex, up to about 2 in. long, coarsely toothed at least in the upper half, the prominent veins or their branches running out to the teeth. Flowers in May, creamy white, few in at first hairy racemes 3⁄4 to 11⁄2 in. long. Petals 1⁄4 to 3⁄8 in. long. Top of ovary clad with a short woolly down. Fruits juicy, roundish, dark purple, about 1⁄2 in. wide.
A native of North America from central Ontario and the Great Lakes west to Alaska, south to British Columbia and Oregon, but absent from the coastal ranges. It has always been rare in British gardens in its typical state, and unlikely to be a success in our oceanic climate. According to R. E. Harris it can survive - 60°F. in its native country, and he mentions a cultivar 'Altaglow' with fine autumn colour (Journ. R.H.S. Vol. 95 (1970), p. 118).
var. semiintegrifolia (Hook.) C.L. Hitchc. A. ovalis var. semiintegrifolia Hook.; A. florida Lindl.; A. alnifolia var. florida (Lindl.) Schneid.; A. oxyodon Koehne. – The differences between this amelanchier, usually known as A. florida, and the typical state of A. alnifolia are not at all clear, but it seems to be on the average more robust in habit, often a tree, with larger flowers and the top of the ovary less hairy to glabrous. Contrary to what has been stated, there is no reliable difference between the two in foliage. However, this variety is better adapted to the British climate, occurring as it does nearer the Pacific, in the Cascade ranges as far south as northern California. It was introduced to Britain by David Douglas in 1826 and the name A. florida Lindl. was based on a plant raised from his seeds, but it has also been grown as A. alnifolia simply. Although pretty enough in flower, it has no special merit.
This amelanchier has been figured twice in the Botanical Magazine. In t.8611 is represented a plant received from a continental nursery as A. oxyodon, which may have been raised from seeds collected by Purpus towards the end of the last century; this was rather anomalous in its dwarf habit and short petals. In t. 9496 the plant figured grew at Dawyck and is of unknown provenance; it differed from the Douglas introduction in its more tomentose inflorescence (A. florida f. tomentosa Sealy).
var. cusickii (Fern.) C.L. Hitchc. A. cusickii Fern. – The only remarkable feature of this variety is that the flowers are very large in some forms, with petals up to 1 in. long. It was described from a specimen collected in Oregon, but occurs elsewhere in western North America.
A. utahensis Koehne A. alnifolia var. utahensis M. E. Jones; A. prunifolia Greene – Allied to A. alnifolia, but with leaves to only about 11⁄2 in. long, which are permanently woolly at least beneath, and with unusually short and relatively broad petals, to about 3⁄8 in. long at the most, borne in late April or early May. Stamens often only four. At Kew the flowers are off-white, very freely borne, but quite uncharacteristic of the genus as usually seen in gardens. Native of the drier parts of the western USA. Introduced towards the end of the last century.
The following seems to be the eastern counterpart of A. alnifolia:
A. sanguinea (Pursh) DC. Pyrus sanguinea Pursh – A stoloniferous shrub to about 10 ft high, which owes its specific epithet to the reddish young branchlets. Leaves coarsely toothed to the base, 11⁄4 to 21⁄2 in. long, similar in shape to those of A. alnifolia except that they are sometimes subacute at the apex and rarely truncate there; veins in twelve to fifteen pairs on each side, the upper ones running out to the teeth. Flowers in lax racemes. Petals to about 5⁄8 in. long, narrow. Top of ovary hairy. Native of eastern North America from the Atlantic to the Great Lakes and Iowa, south to North Carolina. It has been introduced, but has no special merit.
A. amabilis Wieg. A. grandiflora (Wieg.) Wieg., not Rehd.; A. sanguinea f. grandiflora Wieg. – Perhaps only varietally distinct from the preceding, the main difference being apparently that the flowers are larger, with broader petals. It has a limited distribution in eastern Canada, south to New York. It was originally given species rank under the illegitimate name A. grandiflora, which belongs properly to the hybrid mentioned under A. lamarckii.
If all the above species were to be regarded as only subspecifically or varietally distinct, they would have to be grouped under A. sanguinea, which is nomenclaturally the oldest. This is the treatment accorded to them by the Canadian botanist Pierre Landry, who sinks A. amabilis in the typical part of A. sanguinea; and gives varietal rank under it to A. alnifolia (including A. florida) and to A. utahensis (Bull. Soc. Bot. France, Vol. 122, pp. 243-51 (1975)).