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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Understanding Primula moupinensis ssp barkamensis

In 1990, C.M. Hu described a new subspecies of Primula moupinensis from Barkam Xian, Sichuan which differed from the species by its larger flowers to 2.5cm in diameter,  interior leaves with a rounded or slightly cordate base and petioles as long as the leaf blade. The original description lists 9 different collections, though X. Li #70127 at Bejing is designated the holotype. This species was seen before – there is an old collection at Paris (P04544170) which was determined by Marcel Petitmengin (who died in 1908 so before that year) as P. sonchifolia, but later determined by Hu as this subspecies. I don't know who was the original collector of this specimen nor when it was collected.

P. moupinensisssp. barkamensis (L) in flower, (R) in fruit

When I visited Kunming herbarium in 2014, I examined paratype sheets of this subspecies. When in fruit, this species is very easy to identify as the leaves are quite distinct. In flower though, the leaves are oblong-ovate and attenuate at the base, tapering to a short winged petiole that we see in other related species so it is critical to see plants in fruit to accurately identify them. There are several examples online at the Chinese Virtual Herbarium (see the Herbaria and References page under Resources).
There are many plants labelled this subspecies in cultivation, though all I have is images of these plants in flower, so not with the characteristic leaves. If you grow plants of this subspecies, I would be grateful for images of the plant in fruit.

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The Tsari Valley

From where did the snow lion come?

It came forth from the glaciers of Tsari.

It brings joy to the world just by coming

To show off its turquoise mane.

 

Tsari is one of three of the most important pilgrimages in Tibet and it is associated with the divinity Demchok and the mountain called Takpa Shelri, (Pure Crystal Mountain), located at  28°35'58.90"N 93°13'35.44"E. Tradition bans hunting and cultivation in parts of the Tsari valley. There are two main pilgrimage circuits, the Tsari Rongkhor which starts in Chosum and Tsari Kyilkhor which is a lesser circuit around Takpa Shelri. This lesser (central) circuit was hiked by the plant explorers Bailey in 1913 and Sherriff in 1936. In 1998, a party led by Peter Cox made an expedition to the Tsari valley (limited to the north side) with an emphasis on hunting for Rhododendrons. No botanical exploration by Westerners has been done since because of political difficulties (this valley is close to the Indian border), but Chinese botanists have been here in the last 3 years.

Primula odontica in Tsari by Wu Zhikun

Tsari is suddenly (within 25kms) a much wetter valley than those valleys immediately to the west and north and there are many marshy areas. This makes for great Primula habitat. The main valley along the Tsari Chu (river) has masses of P. alpicola (var. violacea), P. calderiana, and P. sikkimensis. In higher alpine areas, P. dickieana, P. tsariensis, P. dryadifolia, P. muscoides, P. rhodochora, P. hookeri, P. tenuiloba, P. munroi ssp yargongensis, P. atrodentata, P. glabra, P. macrophylla, P. prenantha and P. cawdoriana are found. Notably this area is the type location for P. jucunda, P. odontica, P. sandemaniana, P. ioessa and P. flabellifera. Most of these species are little known, but P. odontica was seen and photographed by Chinese botanist Wu Zhikun in 2013 (see in the Species Gallery). It resembles P. kingii and P. valentiniana but with leaves that are prominently toothed.

Primula ioessa remains a difficult plant to assess as it may be part of a continuum of variation with P. sikkimensis, being a dwarf version with pink flowers and dark black calyces. Certainly on the Bimbi La, Tsari, (one of the syntype locations) flower shape and color varies from deep and light pink, to salmon and yellow.

Variation of Primula ioessa on the Bimbi La

For the Primula hunter, Tsari must be one of the most desirable locations to visit.

Location of Tsari valley (orange outline)

References: Seeds of Adventure In Search of Plants by Peter Cox & Peter Hutchison, Tibet Handbook by Victor Chan, The Cult of Pure Crystal Mountain by Toni Huber.

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Herbariums

Type specimens are (usually) dried and pressed plants, mounted on paper, stored in a herbarium and used to describe a new species. Associated with the specimen are details of its collection including where it was collected, when and by whom. Being able to access herbarium specimens is key to understanding what makes a species distinct and what variation the plants exhibit. Under Resources in the main menu of Primula World is a list of Herbaria that has collections of special interest to the study of Primula. This list is always being updated with more links, so check back frequently. If you know of a herbarium that should be on the list, please contact the webmaster. There is a great reference to the kinds of types at the New York Botanic Garden.



RBGE Herbarium image by Paul Macrae (CC BY-NC-ND 2.0) from Flickr

There a several great videos about herbariums below that are worth watching:

 

 

 

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