Syn.: Amellus villosus Pursh, Aster gracilentus Banks ex DC., Chrysopsis villosa (Pursh) Nutt. ex DC., Chrysopsis villosa (Pursh) Nutt. ex Hook., Diplogon falcatum (Pursh) Kuntze, Diplogon villosum (Pursh) Kuntze, Diplopappus villosus (Pursh) Hook., nom. illeg., Diplostephium hispidum Nees ex DC., Inula villosa (Pursh) Nutt., nom. illeg., Sideranthus integrifolius Nutt., nom. illeg.
Family: Asteraceae Bercht. et J. Presl
Heterotheca villosa
Distribution: West of North America, from British Columbia, Alberta and southern Ontario (could be introduced), through Illinois and Oregon to west Texas and California. Highly variable species, 9 varieties are recognized. The nominate variety is the most common and it is found mostly in northern part of the area, to a lesser degree var. ballardii and var. foliosa. The rarest variety H. v. var. depressa occurs in Wyoming (Yellowstone Park), and in Sonora var. pedunculata. The most variable is also very common var. minor with numerous local morphotypes.
Ecology: Nominate variety grows in prairie, grasslands, in sand, along roads and railroads, in elevations 300 to 2300(–2900) m. Blooms from June to November. New Mexican var. sierrablancensis climbs to 2200–3500 m.
Heterotheca villosa
Description: Perennial herb, stems (5–)16–40(–70) cm tall. Stems 1–50, spreading to ascending, hairy and/or glandular. Stem leaves oblong to lanceolate, 2–5 cm long, 2–13 mm wide, stiff to glandular-haired, short stalked, margins smooth to finely toothed. Flower heads one to several, terminal, flowers 25–30 mm across; disc florets yellow, numerous; ray florets 15–35, yellow, 6–10 mm long; bracts bristly to sticky-haired, borne in several overlapping rows. Fruit is an achene, pappus of short outer and longer inner bristles.
Note: The genus belongs to a large group of American asters, to which the following genera belong: Dieteria, Eurybia, Herrickia, Machaeranthera, Oreostemma, Symphyotrichum, Triniteurybia, Xanthisma. The genus contains 28 species altogether, all occurring in Canada, USA and Mexico.
Heterotheca villosaHeterotheca villosa
Heterotheca villosa
Heterotheca villosa
Heterotheca villosa
These images were taken in Canada, Alberta, Calgary, Nose Hill Park (summer 2012 and 3. 10. 2013).