Helianthus couplandii

Prairie Sunflower

Douglas Provincial Park
24-aug-2002

Flora of Alberta keys genus Helianthus as having "at least the lower leaves opposite".  Yet it keys Helianthus petiolaris (=H. couplandii) as having "leaves mostly alternate". 

I have found that neither flora easily distinguishes between Helianthus and Rudbeckia (Rudbeckia hirta is Black-eyed Susan) in their keys.  However, they do note that the leaves of Rudbeckia are always alternate.

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Couplandii Characteristics
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pubescence soft

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leaves mostly alternate

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leaves not cordate based

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leaves entire

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leaves lanceolate to ovate, mostly cuneate at base

 
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Helianthus Characteristics
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plants more or less leafy-stemmed

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plants not with a woody caudex

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leaves not compound

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leaves not linear

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at least the lower leaves opposite