General:
Perennial herb from a rhizome and tuberous-thickened root; stems erect, simple or few, branched above, hairless below the inflorescence or with a few coarse, spreading hairs, 0.6-2 m tall.
Leaves:
Basal leaves lacking; lower leaves opposite; upper leaves alternate, lanceolate to linear, short-stalked, rough-hairy, 8-16 cm long, 6-30 mm wide, entire, flat, 3-nerved at the base.
Flowers:
Heads with ray and disk flowers, solitary to few, terminal; involucres 1.0-2.0 cm tall; involucral bracts lance-linear, loose, inconspicuously hairy on the margins; ray flowers 10-16, 1.5-3 cm long; disk flowers yellow; receptacles convex to low-conic.
Fruits:
Achenes moderately compressed, usually glabrous; pappus of 2 readily deciduous awns with enlarged, thin, papery bases.
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
Synonyms and Alternate Names:
Helianthus nuttallii var. nuttallii T.& G.
Helianthus nuttallii var. rydbergii (Britton) B. Boivin
Helianthus rydbergii Britton