Dodecatheon or Primula? (Updated 2017)

"In my heart two things are true: shooting stars will always belong to Dodecatheon, and, regretfully, all of them are actually members of the genus Primula" - James Reveal

The research paper "Transfer of Dodecatheon to Primula (Primulaceae)" by Austin Mast and James Reveal in Brittonia 59(1):79-82. 2007 (PDF), transferred the species of the Genus Dodecatheon into the Genus Primula under a new Section called Dodecatheon (L.). This was a controversial move for gardeners, especially those in the North American Rock Garden Society (NARGS) whose symbol is a Dodecatheon. One of the coauthors, James Reveal, wrote about the results of this paper in an article (PDF) in the Rock Garden Quarterly (the NARGS journal). He explained that previous research by Austin Mast into the evolutionary history of Primula showed that Dodecatheon falls within the Auriculastrum Subgenus (which includes the well known Section Auricula) and is closest to Section Suffrutescens, which has only one member, Primula suffrutescens.
Primula suffrutescens by Jay Lunn
This Subgenus consists of species which have involute leaf venation, and a base chromosome number of x=11, while Dodecatheon has the same venation and x=22 (meaning Primula is the basal group from which Dodecatheon evolved). Dodecatheon evolved from a common Primula ancestor through the actions of buzz-pollination by bees who prefer the "shooting star" flower arrangement now present in Dodecatheon (see also) . In a meadow of Dodecatheon, you can hear the buzzing noise as bees rapidly move their wings to shake the pollen from the anthers.
Buzz pollination by bee on Dodecatheon
Most of the identification keys are for Dodecatheon and one of the best is this revision by James Reveal.
Section Dodecatheon flower structure from Mitchem, The Plantsman 13(3) 1991.
In 2002, Trift, Källersjö and Anderberg (Systematic Botany 27: 396–407) found that not only does Dodecatheon fall within Primula, so does Cortusa, Sredinskya and Dionysia. While Sredinskya has slipped quietly into Primula as Primula grandis, it seemed as though there was greater reluctance to move Cortusa, though eventually this was done by N. K. Kovtonyuk in 2011 as Primula matthioli. Dionysia still remains separate and will likely to remain so with strong support from Dionysia enthusiasts.

The acceptance of the transfer of Dodecatheon to Primula has been slow. The Flora of North America acknowledges Mast & Reveal's work, but keeps Dodecatheon separate while indicating the new names in synonymy. Later treatments, such as the Jepson eFlora and the Encyclopedia of Life include Dodecatheon in Primula. I now include these species in my Species Gallery though the new names aren't a simple replacement of the name Dodecatheon with Primula, so consult the Mast & Reveal paper for naming.

Primula conjugens var. viscida

Pam Eveleigh © 2017


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