Phylogeny of Selaginellaceae: Evaluation of Generic/Subgeneric Relationships Based onrbcL Gene Sequences

A cladistic analysis based onrbcL gene sequences from a representative sample of 18 species yields three most parsimonious trees that strongly support monophyly of Selaginellaceae. Within Selaginellaceae, the morphologically distinctive subgenusSelaginellais resolved as sister group to a clade compo...

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Bibliographic Details
Published inInternational journal of plant sciences Vol. 160; no. 3; pp. 585 - 594
Main Authors Korall, Petra, Kenrick, Paul, Therrien, James P.
Format Journal Article
LanguageEnglish
Published The University of Chicago Press 01.05.1999
Subjects
Biological taxonomies
Endemic species
Fossils
Leaves
Megaspores
Phylogenetics
Plant morphology
Plants
Stems
Taxa
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Summary:A cladistic analysis based onrbcL gene sequences from a representative sample of 18 species yields three most parsimonious trees that strongly support monophyly of Selaginellaceae. Within Selaginellaceae, the morphologically distinctive subgenusSelaginellais resolved as sister group to a clade composed of all other species, here termed the rhizophoric clade. In the rhizophoric clade, subgenusStachygynandrumis paraphyletic to subgeneraEricetorum,Tetragonostachys, andHeterostachys. Monophyly ofEricetorumandTetragonostachysis strongly corroborated. Results support a close relationship between “resurrection plants” inStachygynandrumand the mat‐forming or tufted drought‐tolerant species ofTetragonostachys, indicating a common origin of xerophytism in these groups. A close relationship for all isophyllous species, as hypothesized in many classifications, is not supported by therbcL data. Leaf isophylly and reduction inEricetorumandTetragonostachysmost probably represent independent reversals of the marked anisophyllous condition inStachygynandrum. Leaf reduction is one of a suite of characters that may have evolved in response to seasonal drought.
ISSN:1058-5893
1537-5315
DOI:10.1086/314137