A deciduous shrub, producing a thicket of erect stems to 10 ft or more high, or a small tree. Leaves roundish oval, 1 to 2 in. long, about two-thirds as wide, rounded at the apex, more rarely bluntly pointed, rounded or slightly heart-shaped at the base, glabrous, or slightly downy when young, margins coarsely toothed above the middle, more rarely in the lower half. Flowers white, about 3⁄4 to 11⁄4 in. across, borne five to fifteen together in erect racemes, which are covered at first with a whitish down but soon glabrous; summit of ovary densely downy at flowering time but soon glabrous. Fruit black-purple, juicy and edible, glabrous. Bot. Mag., t. 8611.
Native of western N. America from S.E. Alaska to W. Oregon and N.W. California; introduced by Douglas in 1826.
f. tomentosa Sealy – Leaves glaucous, slightly downy or glabrous beneath; flower-stalks densely downy. Bot. Mag., t. 9496.
The following related species from western N. America may be mentioned here:
A. alnifolia Nutt. – This species is closely allied to A. florida and the two have been much confused. According to Jones (op. cit.) it is best distinguished by its smaller flowers (to 4⁄5 in. across); also, the leaves are usually rounder and thicker and the habit dwarfer. Its natural range lies further inland, in the Rocky Mountains. Another close relative is A. pallida Greene, native of California, which differs from the two preceding species in the fine, persistent downiness of the leaves beneath; the leaves are also smaller and narrower and the racemes only four- to six-flowered. Much more distinct is:
A. cusickii Fern. – This is the largest-flowered of all the amelanchiers, the flowers being up to 2 in. across. It is a slenderly branched shrub 4 to 10 ft high; leaves quite glabrous even when young. It occupies a small area within the range of A. alnifolia. For a description of this species in its native habitat see B. O. Mulligan in Journ. R.H.S., Vol. 73, 1948, p. 155.
A. utahensis Koehne – A very variable species inhabiting the drier parts of western N. America. It is unusual among the amelanchiers in having only two to four styles instead of the normal five. This peculiarity is also seen in A. pallida, but in that species the leaves are smaller, with nine pairs of veins at the most (eleven to thirteen in A. utahensis). This species has been introduced under various names from different parts of its range, e.g. A. prunifolia Greene, A. rubescens Greene, A. purpusii Koehne. These, however, are best considered (Jones, op. cit.) as states of A. utahensis.