This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
A shrub or small tree, sometimes 30o high, the foliage and inflorescence densely white-woolly when young, often nearly or quite glabrous when old. Leaves oval, oblong, elliptic or obovate, acute or obtuse, rounded, or sometimes narrowed or subcordate at the base, finely and sharply serrate nearly all around; racemes short, rather dense; pedicels short, seldom over 1' long; petals spatulate or linear-spatulate, 5"-7" long, 2-3 times as long as the calyx-lobes; calyx usually densely white-woolly; pome globose, 3"-4" in diameter.
A. nantucketensis Bicknell differs in having shorter petals and thicker leaves, and ranges from Massachusetts to New Jersey.
Stems 1°-3° high from a long root creeping among rocks. Leaves elliptic or oval, 9"-1 1/2' long, rounded at both ends, or sometimes subacute at the apex, sometimes subcordate at the base, serrulate or dentate-serrate nearly all around or sometimes entire below the middle, dark green and quite glabrous when mature, woolly when young; racemes numerous, 4-10-flowered; pedicels slender, 1/2'-1'long in fruit; petals 2"-4" long; calyx-lobes nearly triangular; top of the ovary woolly; pome globose, about 3" in diameter.
Mespilus canadensis var. rotundifolia Michx.
A tall shrub or small tree, sometimes 25o high. Leaves broadly oval, ovate or nearly orbicular, 1'-3' long, obtuse or rounded at both ends, or rarely subacute, often cordate at the base, serrate nearly all around with large teeth, or entire near the base, glabrous from the time of unfolding or more or less woolly when very young; racemes several-flowered; pedicels slender, 1'-1 1/2' long in fruit; calyx-lobes lanceolate; petals spatu-late or oblanceolate, 5"-8" long; pome globose, 3"-4" in diameter.
In woods and thickets, New Brunswick to Minnesota, North Carolina and Michigan. May.