Zhou Xin-Mao, Zhang Liang, Chen Cheng-Wei, Li Chun-Xiang, Huang Yao-Moan, Chen De-Kui, Lu Ngan Thi, Cicuzza Daniele, Knapp Ralf, Luong Thien Tam, Nitta Joel H, Gao Xin-Fen, Zhang Li-Bing
CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu, Sichuan 610041, China; Missouri Botanical Garden, P.O. Box 299, St. Louis, MO 63166-0299, USA.
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
Mol Phylogenet Evol. 2017 Sep;114:271-294. doi: 10.1016/j.ympev.2017.06.020. Epub 2017 Jul 1.
The Old World fern genus Pyrrosia (Polypodiaceae) offers a rare system in ferns to study morphological evolution because almost all species of this genus are well studied for their morphology, anatomy, and spore features, and various hypotheses have been proposed in terms of the phylogeny and evolution in this genus. However, the molecular phylogeny of the genus lags behind. The monophyly of the genus has been uncertain and a modern phylogenetic study of the genus based on molecular data has been lacking. In the present study, DNA sequences of five plastid markers of 220 accessions of Polypodiaceae representing two species of Drymoglossum, 14 species of Platycerium, 50 species of Pyrrosia, and the only species of Saxiglossum (subfamily Platycerioideae), and 12 species of other Polypodiaceae representing the remaining four subfamilies are used to infer a phylogeny of the genus. Major results and conclusions of this study include: (1) Pyrrosia as currently circumscribed is paraphyletic in relation to Platycerium and can be divided into two genera: Pyrrosia s.s. and Hovenkampia (gen. nov.), with Hovenkampia and Platycerium forming a strongly supported clade sister to Pyrrosia s.s.; (2) Subfamily Platycerioideae should contain three genera only, Hovenkampia, Platycerium, and Pyrrosia s.s.; (3) Based on the molecular phylogeny, macromorphology, anatomical features, and spore morphology, four major clades in the genus are identified and three of the four are further resolved into four, four, and six subclades, respectively; (4) Three species, P. angustissima, P. foveolata, and P. mannii, not assigned to any groups by Hovenkamp (1986) because of their unusual morphology, each form monospecific clades; (5) Drymoglossum is not monophyletic and those species previously assigned to this genus are resolved in two different subclades; (6) Saxiglossum is resolved as the first lineage in the Niphopsis clade; and (7) The evolution of ten major morphological characters in the subfamily is inferred based on the phylogeny and various morphological synapomorphies for various clades and subclades are identified.
旧世界的石韦属（水龙骨科）为蕨类植物提供了一个研究形态演化的罕见体系，因为该属几乎所有物种的形态、解剖结构和孢子特征都得到了充分研究，并且针对该属的系统发育和演化提出了各种假说。然而，该属的分子系统发育研究相对滞后。该属的单系性一直不确定，且缺乏基于分子数据的现代系统发育研究。在本研究中，利用代表戟蕨属2个物种、鹿角蕨属14个物种、石韦属50个物种以及舌蕨属（舌蕨亚科）唯一物种的220份水龙骨科植物的5个质体标记的DNA序列，以及代表其余4个亚科的12种其他水龙骨科植物的DNA序列来推断该属的系统发育。本研究的主要结果和结论包括：（1）当前界定的石韦属相对于鹿角蕨属是并系的，可分为两个属：狭义石韦属和霍温坎普属（新属），霍温坎普属和鹿角蕨属形成一个得到有力支持的分支，是狭义石韦属的姐妹分支；（2）舌蕨亚科应仅包含三个属，即霍温坎普属、鹿角蕨属和狭义石韦属；（3）基于分子系统发育、宏观形态、解剖特征和孢子形态，确定了该属的四个主要分支，其中四个分支中的三个又进一步分别解析为四个、四个和六个亚分支；（4）有三个物种，即狭叶石韦、洼穴石韦和曼氏石韦，由于其形态异常，霍温坎普（1986）未将它们归入任何类群，它们各自形成单种分支；（5）戟蕨属不是单系的，先前归入该属的物种被解析到两个不同的亚分支中；（6）舌蕨被解析为拟水龙骨分支中的第一个谱系；（7）基于系统发育推断了该亚科十个主要形态特征的演化，并确定了各个分支和亚分支的各种形态共衍征。
