Sorbus

The bright red fruits of all our species are attractive and persist on the trees until birds get to them, which is usually not long.

1. Sepals, ovary, and winter-buds ± densely white-pubescent; leaflets ± soft-pubescent beneath; rare escapes from cultivation.

S. aucuparia

1. Sepals, ovary, and winter buds (outer scales) glabrous or sparsely pubescent; leaflets glabrous or glabrate over much or all of the surface beneath; native species.

2. Lateral leaflets (3.2–) 3.4–4.5 (–6.4) times as long as broad, ± tapered or acuminate to the sharp apex, usually completely glabrous at maturity; petals (2–) 2.4–3 mm long; pedicels and branches of inflorescence glabrous or nearly so; mature fruit ca. 5–6.5 mm in diameter, not glaucous even when dried.

S. americana

2. Lateral leaflets 2.4–3 (–3.2) times as long as broad, ± abruptly acute to obtuse at the apex, often retaining some pubescence at least along midrib beneath at maturity; petals (2.7–) 3–4.5 mm long; pedicels and branches of inflorescence ± hairy; mature fruit ca. (6–) 8–10 mm in diameter, often becoming glaucous especially in drying.

S. decora

All species found in Sorbus

Sorbus americanaAMERICAN MOUNTAIN-ASH 
Sorbus aucupariaEUROPEAN MOUNTAIN-ASH, ROWAN 
Sorbus decoraMOUNTAIN-ASH 

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. April 25, 2017. http://michiganflora.net/genus.aspx?id=Sorbus.