Psilactis Asters

Psilactis A. Gray is a small southwestern U.S. and Mexican genus of six species following Morgon (1993; Syst Bot 18: 290-308.) differing from other Symphyotrichinae. Species are annuals, biennials or rhizomatous perennials and have dimorphic cypselae with the ray fruit lacking a well developed crown of bristles. Species have been included in Machaeranthera (in the broad sense) in the past (Turner & Horne 1964). The relationships of Psilactis to other Symphyotrichinae taxa was explored by Morgan and Holland (2012); questions about the phylogenetic relationships of the genera and subgenera in the Symphyotrichinae remain unsettled.  The treatment followed here is that of D.R. Morgan (2006 Flora North America.

  • Psilactis asteroides A. Gray
  • Psilactis brevilingulata Schultz-Bipontinus ex Hemsley
  • Psilactis gentryi (Standley) D.R. Morgan
  • Psilactis heterocarpa (R.L. Hartman & M.A. Lane) D.R. Morgan
  • Psilactis odysseus (G.L. Nesom) D.R. Morgan
  • Psilactis tenuis S. Watson

Morgan, D.R. and B. Holland. 2012. Systematics of Symphyotrichinae (Asteraceae: Astereae): Disagreements Between Two Nuclear Regions Suggest a Complex Evolutionary History. Syst. Bot. 37: 818–832.

revised 10 May 2013 by J.C. Semple

© 2013 J.C. Semple, including all photographs unless otherwise indicated