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Ionactis E.L. Greene

STIFF-LEAVED ASTERS

Ionactis is small North American genus of five species (Nesom and Leary 1992) of pink to purple rayed asters with a chromosome base number of x=9. The four species occur at mid to high elevations in the Rocky Mts and Cascade Mts. One species occurs in eastern North America. The genus is distinguished by its stiff leaves, narrow phyllaries with chlorophyllous zone restricted to narrow bands along the raised midrib, and fusiform achenes with a double pappus of two  whorls of long bristles.

Brouillet, Allen, Semple and Ito (2001) fund the genus to be basal in the clade including the Symphyotrichinae, Oreostemma, Herrickia, Eurybia and Nesom's subtribe Machaerantherinae.

Illustrations

• Ionactis alpina (syn: Aster scopulorum); habit
• Ionactis caelestis
• Ionactis elegans
• Ionactis linariifolia; habit
• Ionactis stenomeres; habit, head

Last update 25 October 2005 by J.C. Semple                 © 2005, J.C. Semple