MAST, AUSTIN R.1*, ELENA CONTI1, A. JOHN RICHARDS2, SYLVIA KELSO3, DANIELA LANG1, and D. SKY FELLER1. 1Institute for Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland; 2Department of Agriculture and Environmental Science, Ridley Building, University of Newcastle upon Tyne, NE1 7RU, United Kingdom; 3Colorado College, Biology Department, 14 East Cache La Poudre St., Colorado Springs, CO 80903, USA. - Implications of a two-intron cpDNA phylogeny of Primula (Primulaceae) for the group’s taxonomy and evolutionary history
.
In this, the first molecular study to sample within the genus
Primula at such a large scale, the rpl16 and trnL introns
(cpDNA) have been sequenced from 95 of the ca. 450 species, covering
30 of the 37 sections and 5 of the 6 subgenera. Among the 24
additional accessions are representatives of all genera that are
likely to be embedded in the primula clade, as well as outgroups from
the Maesaceae, Theophrastaceae, and Myrsinaceae. In the strict
consensus of the most parsimonious trees, the primula clade is sister
to a clade of several genera once thought to be nested in it,
including Omphalogramma, Soldanella, and
Hottonia. A trichotomy is formed at the base of the primula
clade by subgenus Auganthus (plus P. dryadifolia, an
enigmatic member of subgenus Aleuritia), subgenus
Auriculastrum, and the remaining subgenera. In this last clade
are the following well-supported relationships: (i) a clade containing
some of the subgenus Aleuritia is sister to subgenus
Sphondylia (and Dionysia, see below), (ii) the clade of
i is sister to subgenus Primula, and (iii) the clade formed by
i and ii is sister to a clade containing the remainder of subgenus
Aleuritia (plus the unplaced section Davidii). Four
genera are embedded in the primula clade: (i) the Eurasiatic genus
Cortusa in subgenus Auganthus, (ii) the North American
genus Dodecatheon in subgenus Auriculastrum, (iii) the
west Asian genus Sredinskya in subgenus Primula, and
(iv) the Middle Eastern genus Dionysia as the sister of
subgenus Sphondylia. Homostyly is resolved as a derived
condition in two sections (Sphondylia and Proliferae)
currently thought to have inherited the primitive homostylous
condition of the primula clade. The evolution of characters that have
played a significant taxonomic role, including chromosome base number,
leaf vernation, and pollen type, will also be discussed in light of
the phylogeny.
Key words: Cortusa, cpDNA phylogeny, Dionysia, Dodecatheon, heterostyly, Primula