Sorbus scopulina, American mountain ash

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Intermountain Flora
Shrub or small tree, 1-4 m tall, the bark yellowish to reddish-purple, becoming grayish-red; herbage strigose-pilose, the stems becoming sparsely so and the leaves becoming glabrate; winter buds glutinous-brown, glossy, glabrous to sparsely whitish-pubescent; leaves 11-or 13-pinnate, 14-21 cm long, the rachis grooved above and glandular -pubescent near the nodes, the petiole 2-3.5 (4.5) cm long, the leaflets broadly lanceolate or elliptic, 4-7.5 (8.5) cm long, (1.5) 1.7-2.5 cm wide, rounded to abruptly cuneate basally, acute or usually acuminate apically, finely serrate almost to the base, dark, glossy green above, dull, pale green and sparsely pubescent beneath; corymb more or less flat-topped, 80-200 flowered, white-appressed-pilose on the pedicels, hypanthium, and sepals, the flowers fragrant; sepals deltate, 0.7-1.8 mm long, acute or obtuse; petals (ob)ovate, 3-5 (6) mm long, white or cream; stamens 20, the filaments 2.5-4 mm long, the anthers 0.5-0.7 mm long; styles 3 or 4; pome globose, 8-10 mm thick, bright glossy orange-red, drying purplish, of bitter taste; seeds oblong, 3.5-4 mm long, flattened, light brown.

Cronquist, A., Holmgren, N.H., and Holmgren, P.K. (1997) "Intermountain Flora" pg. 150, vol. 3 part A, The New York Botanical Garden New York.