Date Published: March 31, 2017
Publisher: Public Library of Science
Author(s): Nan Jiang, Zhuang Zhou, Jun-Bo Yang, Shu-Dong Zhang, Kai-Yun Guan, Yun-Hong Tan, Wen-Bin Yu, Tzen-Yuh Chiang.
Morphological and molecular evidence strongly supported the monophyly of tribe Anemoneae DC.; however, phylogenetic relationships among genera of this tribe have still not been fully resolved. In this study, we sampled 120 specimens representing 82 taxa of tribe Anemoneae. One nuclear ribosomal internal transcribed spacer (nrITS) and six plastid markers (atpB-rbcL, matK, psbA-trnQ, rpoB-trnC, rbcL and rps16) were amplified and sequenced. Both Maximum likelihood and Bayesian inference methods were used to reconstruct phylogenies for this tribe. Individual datasets supported all traditional genera as monophyletic, except Anemone and Clematis that were polyphyletic and paraphyletic, respectively, and revealed that the seven single-gene datasets can be split into two groups, i.e. nrITS + atpB-rbcL and the remaining five plastid markers. The combined nrITS + atpB-rbcL dataset recovered monophyly of subtribes Anemoninae (i.e. Anemone s.l.) and Clematidinae (including Anemoclema), respectively. However, the concatenated plastid dataset showed that one group of subtribes Anemoninae (Hepatica and Anemone spp. from subgenus Anemonidium) close to the clade Clematis s.l. + Anemoclema. Our results strongly supported a close relationship between Anemoclema and Clematis s.l., which included Archiclematis and Naravelia. Non-monophyly of Anemone s.l. using the plastid dataset indicates to revise as two genera, new Anemone s.l. (including Pulsatilla, Barneoudia, Oreithales and Knowltonia), Hepatica (corresponding to Anemone subgenus Anemonidium).
Tribe Anemoneae is a member of subfamily Ranunculoideae (Ranunculaceae) [1–4]. Traditionally, this tribe included three subtribes, i.e., Anemoninae, Clematidineae and Kingdoniae [1–3]. An overview of classifications for tribe Anemoneae is summarized in S1 Table. The subtribe Kingdoniae contains only one species, Kingdonia uniflora Balf. f. & W. W. Sm., which is characterized by one cordate-orbicular leaf, veins bifurcated and a short flower stalk with a small flower. Kingdonia uniflora grows at high elevations in western China . Currently, morphological and molecular evidences show that K. uniflora should be excluded from tribe Anemoneae, even from Ranunculaceae , and it has been treated as an independent family Kingdoniaceae, or incorporated into family Circaeasteraceae since 2009 [4, 7]. Excluding K. uniflora, tribe Anemoneae was strongly supported as monophyletic in phylogenetic analyses [4, 8–11].
Monophyly of tribe Anemoneae has been demonstrated by several studies [4, 8–11]. However, phylogenetic relationship among genera was not full resolved, due to limited DNA markers were used, and/or incomplete genera samplings were analyzed. In this study, we included nine of ten recognized genera in tribe Anemoneae (only Metanemone was not sampled) and used one nuclear and six plastid markers to reconstruct a comprehensive phylogeny of tribe Anemoneae. Based on evaluation of topological incongruence, seven DNA markers were classified as two groups, nrITS and atpB-rbcL, and the remaining five plastid genes. The combined datasets resolved tribe Anemoneae as three major clades: clade 1 included Anemoclema and Clematis s.l. (including Archiclematis and Naravelia), clades 2 and 3 corresponded to Anemone subgenus Anemone (including Barneoudia, Knowltonia, Oreithales, and Pulsatilla), and subgenus Anemonidium (including Hepatica), respectively. The nrITS + atpB-rbcL supported the monophyletic of Anomone s.l. (including clades 2 and 3). However, the five-plastid-gene dataset made subgenus Anemone (clade 2) sister to the clade Anemoclema + Clematis s.l. (clade 1). Our results strongly supported to subsume Archiclematis and Naravelia within Clematis s.l., and to retain Anemoclema as an independent genus. For the genus Anemone s.l., all analyses supported to include Barneoudia, Knowltonia, Oreithales, and Pulsatilla in this genus. However, the five-plastid-gene dataset tended to retain Hepatica as a separated genus, corresponding to Anemone subgenus Anemonidium. Therefore, the updated tribe Anemoneae consists of four revised genera, Anemoclema, Anemone s.l., Clematis s.l. and Hepatica, and an unresolved genus, Metanemone.