Arenaria congesta

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".

Flora of Alberta states that the achenes of genus Helianthus bear a "pappus of small scales or awns, soon falling off".

Budd's Flora keys genus Helianthus as having "achenes without barbed awns" (italics my own).

It also keys genus Helianthus as having "pappus composed of scales, bristles, or barbs"; not "pappus absent, or present merely as a short crown".

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 receptacles of Rudbeckia are more conic and the leaves always alternate.

Couplandii Characteristics

annual plants

pubescence soft

leaves mostly alternate

leaves not cordate based

leaves entire

leaves lanceolate to ovate, mostly cuneate at base

involucre bracts gradually attenuate, without conspicuous, long marginal hairs

receptacle flat or nearly so

disk purple or dark brown

scales between disk florets each with tuft of hairs

Helianthus Characteristics

juice watery, not milky

plants not heavy scented

plants more or less leafy-stemmed

plants not with a woody caudex

leaves not compound

leaves not linear

at least the lower leaves opposite

involucre not glandular nor glutinous

involucre bracts in one or more series, but all of the same nature

receptacle flat or convex, not conic or columnar

receptacle with chaffy scales between the florets

flower heads with both tubular and ray florets

rays conspicuous

ray florets yellow

ligulate (ray) flowers either pistillate or neutral

pappus composed of small scales or awns, soon falling off; not composed of hairs