On the Phylogenetic Position of Cystodium: It’s Not a Tree Fern – It’s a Polypod!
نویسندگان
چکیده
—The phylogenetic position of Cystodium J. Sm. is studied here for the first time using DNA sequence data. Based on a broad sampling of leptosporangiate ferns and two plastid genes (rbcL and atpB), we show that Cystodium does not belong to the tree fern family Dicksoniaceae, as previously thought. Our results strongly support including Cystodium within the large polypod clade, and suggest its close relationship to the species-poor grade taxa at the base of the polypod topology (Sphenomeris and Lonchitis, or Saccoloma in this study). Further studies, with an expanded taxon sampling within polypods, are needed to fully understand the more precise phylogenetic relationships of Cystodium. Cystodium J. Sm., with its single species C. sorbifolium (Sm.) J. Sm., has traditionally been included in Dicksoniaceae (Christensen, 1938; Pichi Sermolli, 1977; Tryon and Tryon, 1982; Kramer, 1990; Stevenson and Loconte, 1996) and, more specifically, has been considered to be closely related to Dicksonia L’Hér. (Hooker, 1844; Copeland, 1947; Holttum and Sen, 1961). Cystodium grows in lowland rainforests from Borneo to New Guinea and adjacent islands such as the Bismarck and Louisiade Archipelagos, and the Solomon Islands (Holttum, 1963; Croft, 1986; Kramer, 1990). It has a creeping, hairy, dictyostelic rhizome with large, bipinnate leaves that are two meters or more in length (Croft, 1986). The terminal sori are covered by a true indusium 1 Corresponding author. Current address: Department of Phanerogamic Botany, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, SWEDEN. E-mail: petra.korall@ nrm.se. American Fern Journal 96(2):45–53 (2006)
منابع مشابه
Contrasting Predictors of Fern versus Angiosperm Decomposition in a Common Garden
We evaluated differences in the rates and correlates of decomposition among 32 fern and angiosperm litter types collected in Hawai’i. Leptosporangiate ferns were separated into groups based on phylogeny: ‘polypod’ ferns, a monophyletic clade of ferns that diversified in the Cretaceous, and all other (‘non-polypod’) ferns that diversified earlier. We measured initial litter chemistry (nutrients ...
متن کاملPhylogenetic Relationships of the Fern Cyrtomium falcatum (Dryopteridaceae) from Dokdo Island Based on Chloroplast Genome Sequencing
Cyrtomium falcatum is a popular ornamental fern cultivated worldwide. Native to the Korean Peninsula, Japan, and Dokdo Island in the Sea of Japan, it is the only fern present on Dokdo Island. We isolated and characterized the chloroplast (cp) genome of C. falcatum, and compared it with those of closely related species. The genes trnV-GAC and trnV-GAU were found to be present within the cp genom...
متن کاملPhylogeny and morphological traits evolution of Astragalus sects. Acanthophace and Aegacantha in Iran on the basis of nrDNA ITS and rpl32-trnLUAG sequences
In this study, phylogenetic relationships and evolutionary trends of morphological characters of Astragalus sects. Acanthophace and Aegacantha were studied using nrDNA ITS and rpl32-trnLUAG datasets while Astragalus stocksii was selected as the outgroup. The phylogenetic results indicated the non-monophyly of A. sect. Acanthophace in its current circumscription due to the distant exclusion of A...
متن کاملA Plastid Phylogeny of the Cosmopolitan Fern Family Cystopteridaceae (Polypodiopsida)
Among the novel results of recent molecular phylogenetic analyses are the unexpectedly close evolutionary relationships of the genera Acystopteris, Cystopteris, and Gymnocarpium, and the phylogenetic isolation of these genera fromWoodsia. As a consequence, these three genera have been removed from Woodsiaceae and placed into their own family, the Cystopteridaceae. Despite the ubiquity of this f...
متن کاملPhylogenetic Relationships of the Fern Cyrtomium falcatum (Dryopteridaceae) from Dokdo Island, Sea of East Japan, Based on Chloroplast Genome Sequencing.
Cyrtomium falcatum is a popular ornamental fern cultivated worldwide. Native to the Korean Peninsula, Japan, and Dokdo Island in the Sea of Japan, it is the only fern present on Dokdo Island. We isolated and characterized the chloroplast (cp) genome of C. falcatum, and compared it with those of closely related species. The genes trnV-GAC and trnV-GAU were found to be present within the cp genom...
متن کامل