Amelanchier alnifolia
 
Saskatoon

Flower Top, Stage 4

Struthers Lake Regional Park
27-May-2011

Note the 20 stamens.  One of them has a large, unopened anther while the rest have smaller, opened anthers.  Flora of the Great Plains states that this species has 15-20 (uncommonly 10) stamens.

Alnifolia: Answers to key questions in Budd's Flora leading to this species. 

pedicels short, mostly 6-8 mm; NOT [pedicels long, the lower ones 15-20 mm long]

 

Amelanchier: Answers to key questions in Budd's Flora and Flora of Alberta leading to this genus. 

shrubs or trees; NOT [herbs, or with a woody base and otherwise herbaceous]

plants taller; NOT [creeping dwarf shrubs]

stems not thorny; NOT [stems with stout thorns]

leaves simple; NOT [leaves compound or lobed]

leaves serrate or toothed; NOT [leaves entire] (BF)

leaves entire to toothed; NOT [leaves mostly incised-toothed or lobed] (FOA)

flowers usually more numerous; NOT [flowers solitary on a long peduncle]

NOT [flowers in broad compound corymbs]

ovary inferior, enclosed in and adnate to the hypanthium; NOT [ovary or ovaries superior, hypanthium free from the ovary]

fruit fleshy; NOT [fruit a leathery follicle]

fruit a berry-like pome with several seeds; NOT [fruit a red or black drupe with a single stone]

 

Rosaceae: Answers to key questions in Budd's Flora  leading to this family. 

herbs; NOT [shrubs or trees]

plants terrestrial or semiaquatic; NOT [plants aquatic, leaves submerged or floating]

plants NOT with colored milky juice

plants with more than one normal leaf

some or all leaves alternate; NOT [leaves opposite, whorled, or basal]

leaves with stipules; NOT [leaves without stipules, or having glands]

flowers with two floral rings, and with each petal distinct from the others

flowers regular in shape; NOT [flowers irregular in shape]

calyx regular; NOT [calyx irregular, some sepals smaller than others]

stamens usually separate or partly so, not in a column; NOT [stamens numerous, united into a column]

ovary of one or more carpels, either separate or enclosed by a fleshy receptacle; NOT [ovary of 5 united carpels]