Common Name: Saskatoon Serviceberry, Western Serviceberry, Pacific Serviceberry, Alder-leaf Shadbush, Dwarf Shadbush, or Western Juneberry

H&C lists 5 "poorly defined" varieties while USDA only lists 4 (no var. pumila)

var. humptulipensis: Generally 4 styles, ovary strongly pubescent, leaves with few teeth, >2 length to width ratio. Petal base width > 3mm. Found southern Olympic Mtns & sw WA.
var. alnifolia: Generally 5 styles, leaves are various but upper half are strongly toothed. Found mostly e Cascades Mtn. [Not found in Columbia River Gorge].
var. semiintegrifolia: ovary tops are densely wooly hairy and greyish. Petals are < 16mm with narrow petal width at base. Plant is tree like. Common variety in w. Cascades Mtn.
var. cusickii: Ovary glalulous (smooth) to tomentose (wooly hairy), but not greyish. Long petals (> 16mm) with a wide base. Freely integrates with others. Found e Cascades including Columbia River Gorge.

These are a good study in what constitutes a "variety or subspecies".
As Hitchcock and Cronquist (H&C) state the varieties listed were "poorly defined". A variety needs both morphological and additional characteristics (geologic separation, ecological and/or phylogenetic differences) to be a variety. I've based my identification on petal size, leaf shape, and location. Something to look for when out in the field.