Prunus pensylvanica
 
Pin Cherry

Pyrene Longitudinal Section

Meadow Lake Provincial Park
11-August-2008

Note the key to the species in Flora of Alberta requires that the petioles of P. pensylvanica be glandular at the upper end, while the petioles of P. virginiana have no glands at the upper end.  In fact, both species usually have glands at the upper ends of their petioles.  The rest of the answers to the key questions appear below.

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Pensylvanica: Answers to key questions in Budd's Flora and Flora of Alberta leading to this species. 
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tall shrub or small tree; NOT [low shrub]

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leaves lanceolate; NOT [leaves elliptic to obovate]

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leaves irregularly serrulate with rounded teeth; NOT [leaves sharply serrate]

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leaves long-acuminate; NOT [leaves abruptly short-acuminate]

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flowers in corymbs; NOT [flowers in umbels], NOT [flowers in long racemes at the ends of the branches]

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flowers 12-25 mm across; NOT [flowers 6-12 mm across]

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stone NOT flattened; NOT [stone more or less flattened]

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stone NOT grooved; NOT [stone with a groove on the end]

 

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Prunus: Answers to key questions in Budd's Flora  and Flora of Alberta leading to this genus. 
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shrubs or trees; NOT [herbs, or with a woody base and otherwise herbaceous]

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plants taller; NOT [creeping dwarf shrubs]

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plants NOT spiny

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leaves simple; NOT [leaves compound or lobed]

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leaves serrate or toothed; NOT [leaves entire]

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

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

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carpel 1; NOT [carpels 2 or more]

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fruit fleshy; NOT [fruit a leathery follicle]

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

 

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Rosaceae: Answers to key questions in Budd's Flora  leading to this family. 
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herbs; NOT [shrubs or trees]

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

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plants NOT with colored milky juice

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plants with more than one normal leaf

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

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

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

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

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

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

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