familyAsteraceae
genusHelianthus
speciesHelianthus nuttallii
subspeciesHelianthus nuttallii subsp. rydbergii
Helianthus nuttallii subsp. rydbergii
Brittonia 18: 77. 1966.
Common names: Rydberg’s sunflower
Endemic
Basionym: Helianthus rydbergii Britton Man. Fl. N. States, 993. 1901
Treatment appears in FNA Volume 21. Treatment on page 167.
Plants usually 100–250 cm. Leaves all or mostly opposite; blades lanceolate to nearly ovate, apices acute to obtuse, abaxial faces hispid to hispidulous. Phyllaries: abaxial faces ± glabrate or sparsely hairy (longer hairs 0.5–1 mm).
Phenology: Flowering late summer–fall.
Habitat: Open areas, sandy dry soils, wet places
Elevation: 200–1000 m
Distribution
Alta., Man., Ont., Que., Sask., Colo., Iowa, Minn., Mont., Nebr., N.Dak., S.Dak.
Discussion
Selected References
None.
Lower Taxa
None.