2. Sorbus intermedia (Ehrhart) Persoon, Syn. Pl. 2: 38. 1806.
Pyrus intermedia Ehrhart, Gartenkalender 4: 197. 1784; Aria intermedia (Ehrhart) Schur
Trees, to 70[–200] dm. Stems 1; bark gray; winter buds green to red-brown, ovoid, 5–12 mm, shiny, slightly glutinous, whitish-villous. Leaves simple; stipules early deciduous, densely whitish-villous; blade shiny, green to dark green adaxially, ovate to elliptic, 6–13 × 3.5–8.5 cm, margins proximally 4–7 pinnately lobed, lobes ˂± oblong˃, 1–1.5(–1.8) cm wide, basal sinuses deepest, margins distally coarsely serrate, main pairs of secondary veins 8–10, apex acute to obtuse, abaxial surface white-tomentose, adaxial glabrous or sparsely villous, indument usually persistent. Panicles 18–85-flowered, rounded, 6–17 cm diam.; peduncles white-tomentose. Pedicels white-tomentose. Flowers 14–16 mm diam.; hypanthium whitish-tomentose, hypanthium plus sepals 5–6 mm; sepals 1.5–2.5 mm, margins villous and eglandular, rarely with inconspicuous glands; petals white, elliptic to broadly ovate, 5–7 mm; stamens 20; carpels distinct, apex conic, styles 2, 2.5–4 mm. Infructescences thinly white-tomentose to glabrate. Pomes bright red, ellipsoid, sometimes narrowly obovoid, 7–16 × 6–11 mm, shiny, faintly glaucous; ˂lenticels few˃; sepals inconspicuous, erect, ˂villous toward apex˃. Seeds red-brown, narrowly ovoid, 6–6.5 × 2.5–3.1 mm, slightly asymmetric, slightly flattened. 2n = 68 (Europe).
Flowering spring; fruiting fall. Thickets, roadsides, waste ground, disturbed conifer forests; 0–100 m; introduced; B.C., Ont.; Mass., Wash.; Europe.
Sorbus aria (Linnaeus) Crantz of Europe has been reported from San Juan County, Washington (S. Atkinson and F. Sharpe 1993; J. T. Kartesz and C. A. Meacham 2003). Those populations are S. intermedia, with more deeply lobed leaves and broader winter buds.