The Cascade Asters
Eucephalus Nutt. is an western North American genus of 9 species of white and purple rayed asters with a chromosome base number of x=9. The majority of the species occur in the Cascade Moutains of the Pacific northwestern United States and southern British Columbia, Canada. The genus is defined on the basis of fruit, hair and phyllary traits; fruits have a quadruple pappus of a short outer series and three mid to longer series, the innermost the longest and strongly clavate; hairs are twisted and form a wooly indument when dense; phyllaries have a thickened (keeled) base. Eucephalus has been treated as Aster sect. Eucephalus, but Xiang and Semple (1996) determined that the genus was not closely related to Aster s.str. and the Symphyotrichum asters. Brouillet, Allen, Semple and Ito (2001) and Brouillet et al. (2009) found the Eucephalus-Doellingeria clade to be basal to all other North America Astereae. Allen, Brouillet and Semple (2001) explored relationships and geographic patterns of subclades within the Eucephalus-Doellingeria clade. They found that two species, H. glauca (A. glaucodes) and H. wasatchensis, usually included in Eucephalus belonged in the Eurybia group, as Nesom (1994) had proposed but based on DNA data are now included in Herrickia (Brouillet 2006).
The treatment here follows Allen (2006 FNA):
- Eucephalus breweri (syn: Chrysopsis b.; Heterotheca b.)
- Eucephalus elegans (syn: Aster perelegans)
- Eucephalus engelmannii
- Eucephalus glabratus
- Eucephalus glaucescens
- Eucephalus gormanii
- Eucephalus gormanii × ledophyllus
- Eucephalus ledophyllus
- Eucephalus paucicapitatus
- Eucephalus tomentellus (A. brickellioides)
- Eucephalus vialis
Allen, G.A. 2006. Eucephalus Nuttall. pp. 39-42. In Flora North America Editorial Committee, eds. Flora of North America. Vol. 20. Asteraceae, Part 2. Astereae and Senecioneae. Oxford University Press, New York.
Brouillet, L. 2006. Herrickia Wooton & Standley. pp. 361--365. In Flora North America Editorial Committee, eds. Flora of North America. Vol. 20. Asteraceae, Part 2. Astereae and Senecioneae. Oxford University Press, New York.
Last updated 8 February 2014 by J.C. Semple
© 2014 J.C. Semple, including all photographs unless otherwise indicated