Betula pumila
 
Swamp Birch

Lower Stem

Duck Mountain Provincial Park
29-June-2007

Note the brown bark.

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Pumila: Answers to key questions in Budd's Flora and Flora of Alberta leading to this species. 
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shrubs seldom over 2 m high; NOT [trees or tall shrubs 3 m or more high]

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reddish or brown bark; NOT [white, papery bark]

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twig pubescent with scattered hairs; NOT [twig indistinctly puberulent with short hairs]

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twig somewhat glandular; NOT [twig densely glandular]

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petiole under 1 cm long; NOT [petiole 1 cm or more long]

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leaf usually under 3 cm long; NOT [leaf usually over 3 cm long]

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leaf obovate; NOT [leaf orbicular]

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leaves tapering at base; NOT [leaves rounded at base]

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leaf with 10 or more teeth each side; NOT [leaf with 10 or fewer teeth each side]

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leaf with 4 or more lateral veins; NOT [leaf with 3 or fewer lateral veins]

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leaf relatively thick and stiff; NOT [leaf membranous]

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samara wings more than half as wide as nutlet; NOT [samara wings less than half as wide as nutlet]

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samara wings narrower than nutlet; NOT [samara wings at least as wide as nutlet body]

 

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Betula: Answers to key questions in Budd's Flora and Flora of Alberta leading to this genus. 
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staminate flowers usually three in the axils of the catkin bracts; NOT [staminate flowers solitary in the axils of the catkin bracts]

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stamens 2; NOT [stamens 4]

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pistillate catkin elongated; NOT [pistillate flowers few in a short, bud-like catkin]

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bracts of pistillate catkins thin; NOT [bracts of pistillate catkins becoming thick and woody]

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bracts of pistillate catkins deciduous; NOT [bracts of pistillate catkins persistent]

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bracts of pistillate catkins 3-lobed

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fruit a nutlet in the axil of a catkin bract; NOT [fruit a nut enclosed in a hispid, leafy involucre with a long beak]

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fruit often winged

 

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

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flowers with only one floral ring, with sepals but not petals

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male flowers, at least, in catkins or aments; NOT [flowers not in catkins or aments]

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styles 2; NOT [styles 3]

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fruit NOT an acorn

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seeds WITHOUT a tuft of hairs