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.

Couplandii Characteristics

pubescence soft

leaves mostly alternate

leaves not cordate based

leaves entire

leaves lanceolate to ovate, mostly cuneate at base

 

Helianthus Characteristics

plants more or less leafy-stemmed

plants not with a woody caudex

leaves not compound

leaves not linear

at least the lower leaves opposite