Molecular phylogenetics and floral evolution in the sarracenioid clade (Actinidiaceae, Roridulaceae and Sarraceniaceae) of Ericales

Autor(en)
Stefan D. Loefstrand, Jürg Schönenberger
Abstrakt

The sarracenioid families (Actinidiaceae, Roridulaceae, Sarraceniaceae) were rarely affiliated with other ericalean taxa in pre-molecular classifications and have seldom been considered closely related to each other. In molecular phylogenetic studies, the sarracenioids form a strongly supported clade and are sister to the ericoid clade (Clethraceae, Cyrillaceae, Ericaceae); the sarracenioids and ericoids together make up core Ericales. To date, no phylogenetic study has included all sarracenioid genera (Actinidia, Clematoclethra and Saurauia in Actinidiaceae; Roridula in Roridulaceae; Darlingtonia, Heliamphora and Sarracenia in Sarraceniaceae). In particular, the monophyly of Saurauia has not previously been tested using molecular characters. We shed light on the phylogenetic relationships within the sarracenioid clade and, based on ancestral state reconstructions, test floral characters previously suggested as potential synapomorphies for the sarracenioids and ericoids. Phylogenetic analysis was performed for the DNA regions ITS, rbcL, rpl32-trnL, trnK and trnL-F using RAxML, MrBayes and PAUP*. Our results support the monophyly of the sarracenioid clade as well as of all its families and non-monotypic genera. Two distinct geographical lineages are identified in Saurauia; the two lineages are characterised by differences in petal union (choripetaly versus sympetaly), style union (free versus partially united), gynoecium merism and base chromosome numbers. Our analyses identify the following floral characters as synapomorphic for core Ericales: adaxial anther attachment, anther inversion and a depression at the ovary-to-style transition. Proximally thick to massive petals, the presence of a nucellar hypostase in ovules and polystemony are synapomorphies of the sarracenioid clade. The presence of calcium oxalate raphides, mucilage cells, a secretory inner gynoecium surface and the absence of synlateral vasculature in the ovary are synapomorphies of the Actinidiaceae-Roridulaceae clade. A two-whorled androecium is a synapomorphy of the ericoid clade.

Organisation(en)
Department für Botanik und Biodiversitätsforschung
Journal
Taxon
Band
64
Seiten
1209-1224
Anzahl der Seiten
16
ISSN
0040-0262
Publikationsdatum
12-2015
Peer-reviewed
Ja
ÖFOS 2012
106008 Botanik, 106042 Systematische Botanik, 106012 Evolutionsforschung
Schlagwörter
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/molecular-phylogenetics-and-floral-evolution-in-the-sarracenioid-clade-actinidiaceae-roridulaceae-and-sarraceniaceae-of-ericales(56889a95-3738-4551-a371-c665b3b84fad).html