Phylogeny of Saururaceae Based on Morphology and Five Regions from Three Plant Genomes

Abstract

Phylogenetic relationships of the six extant species of four genera of the Saururaceae are resolved based on sequence data: 18S and ITS from the nuclear genome; rbcL and trnL-F from the chloroplast genome; and matR from the mitochondrial genome. Zippelia begoniaefolia, from a genus of Piperaceae, is used as an outgroup. Results are presented in separate and combined analyses of sequence data. Forty-nine morphological characters reconstruct the phylogeny in this family, again using Zippelia as outgroup. Whether the topologies of Saururaceae are based on individual genomic data sets, the combined DNA sequence data sets, morphological data sets, or the combined DNA sequence and morphological data sets, all are closely congruent. In all analyses, the monophyly of Saururus and Gymnotheca, respectively, is strongly supported, and the sister relationship between Gymnotheca and Saururus is well supported. In the analysis of nuclear DNA data sets, Anemopsis is the sister group to all other Saururaceae, with Houttuynia then sister to Saururus and Gymnotheca, and with Saururas sister to Gymnotheca; however, in the analyses of the other data sets, Anemopsis is the sister group of Houttuynia, and the Anemopsis-Houttuynia clade lies sister to the Saururus-Gymnotheca clade. The result that the Anemopsis-Houttuynia clade comprises the sister group of Saururus-Gymnotheca clade is novel and differs from previous phylogenetic opinion.