Sorbus americana is a relatively small tree, reaching in height. It resembles the European mountain-ash,
Sorbus aucuparia. ; Bark: Light gray, smooth, surface scaly.
Branchlets downy at first, later become smooth, brown tinged with red,
lenticular, finally they become darker and the papery outer layer becomes easily separable. ; Wood: Pale brown; light, soft, close-grained but weak.
Specific gravity, 0.5451; weight of cu. ft., 33.97 lbs. ; Winter
buds:Dark red, acute, one-fourth to three-quarters of an inch long. Inner scales are very
tomentose and enlarge with the growing shoot. ; Leaves:
Alternate,
compound,
odd-pinnate, long, with slender, grooved, dark green or red
petiole.
Leaflets 13 to 17,
lanceolate or long oval, two to three inches long, one-half to two-thirds broad, unequally wedge-shaped or rounded at base,
serrate,
acuminate,
sessile, the terminal one sometimes borne on a stalk half an inch long, feather-veined,
midrib prominent beneath, grooved above. They come out of the bud downy,
conduplicate; when full grown are smooth, dark yellow green above and paler beneath. In autumn they turn a clear yellow.
Stipules leaf-like,
caducous. ; Flowers:May, June, after the leaves are full grown. Perfect, white, one-eighth of an inch across, borne in flat compound cymes three or four inches across.
Bracts and
bractlets
acute, minute, caducous. ;
Calyx: Urn-shaped, hairy, five-lobed; lobes, short, acute,
imbricate in bud. ;
Corolla:
Petals five, creamy white,
orbicular, contracted into short claws, inserted on calyx, imbricate in bud. ;
Stamens: Twenty to thirty, inserted on calyx tube;
filaments thread-like; anthers introrse, two-celled; cells opening longitudinally. ;
Pistil: Two to three
carpels inserted in the bottom of the calyx tube and united into an inferior
ovary.
Styles two to three;
stigmas capitate;
ovules two in each cell. ; Fruit: Berry-like
pome, globular, one-quarter of an inch across, bright red, borne in
cymous clusters. Ripens in October and remains on the tree all winter. Flesh thin and sour, charged with
malic acid; seeds light brown, oblong, compressed;
cotyledons fleshy. == Distribution ==