Sorbus scopulina

Western Mountain Ash

Leaf Bottom (13 leaflets)

Duck Mountain Provincial Park
30-August-2008

Both Budd's Flora and Flora of Alberta uses the number of leaflets to distinguish this species from others in the genus.  However, the number of leaflets of S. Scopulina can vary from 9-13.

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Scopulina: Answers to key questions in Budd's Flora (BF)  and Flora of Alberta (FOA) leading to this genus. 
bulletshrubs or small trees less than 5 m high; NOT [trees 6-10 m high]
bulletwinter-buds glabrous, glutinous or rufous-pilose; NOT [winter-buds densely white-villose]
bulletleaflets usually 11-13; NOT [leaflets usually 7-11] 
bulletleaflets generally less than 13; NOT [leaflets 13 or more]
bulletleaflets acute or acuminate at apex; NOT [leaflets rounded at the apex]
bulletleaflets serrate to near the base; NOT [leaflets entire toward the base]
bulletyoung twigs and inflorescence white-pubescent; NOT [young twigs and inflorescence with rust-coloured hairs]
bulletinflorescence broad, flat-topped; NOT [inflorescence small, rounded]
bulletstyles 3-5; NOT [styles 2-3]

 

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Sorbus: Answers to key questions in Budd's Flora (BF)  and Flora of Alberta (FOA) leading to this genus. 
bulletsmall trees; NOT [shrubs], NOT [herbs, or with a woody base and otherwise herbaceous]
bulletleaves pinnately compound; NOT [leaves simple], NOT [leaves lobed]
bulletleaflets 11-17; NOT [leaflets 3-11]
bulletflowers in broad compound corymbs
bulletflowers white; NOT [flowers yellow or pink]
bulletovary inferior, enclosed in and adnate to the hypanthium; NOT [ovary or ovaries superior, hypanthium shaped like a saucer, cup or urn and free from the ovary]
bulletfruit a pome but often berry-like, more or less fleshy; NOT [fruit dry]

 

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Rosaceae: Answers to key questions in Budd's Flora leading to this family.  These answers do not apply to all members of the Rosaceae family, but they all do apply to this species.
bulletshrubs or trees; NOT [herbs]
bulletplants NOT climbing
bulletplants with normal leaves
bulletleaves alternate; NOT [leaves opposite]
bulletleaves compound; NOT [leaves simple]
bulletleaflets NOT leathery
bulletleaflets NOT spinose-tipped
bulletflowers with two floral rings, and with each petal distinct from the others]
bulletflowers perfect; NOT [flowers dioecious or perfect]
bulletflowers NOT legume-like
bulletpetals 5
bulletstamens numerous; NOT [stamens 5]
bulletfruit not a legume