Kirkpatrick, Ruth .
Phylogeny, character evolution, and a proposed taxonomic revision for pellaeoid ferns and their relatives.
CHEILANTHOID ferns, including Pellaea and close relatives, are a fascinating component of the floras of arid regions worldwide. The historic inability to decipher natural evolutionary lineages within this group has been attributed to morphological convergence associated with adaptation to xeric habitats. Recent molecular analyses have provided insights into natural evolutionary lineages among cheilanthoids. In this study the chloroplast gene rps4 and intergenic spacers rps4-trnS and trnL-F were used to explore the relationships among sections Pellaea and Platyloma of Pellaea, Astrolepis, Paraceterach, Paragymnopteris, Argyrochosma, and American Cheilanthes. Well-supported pellaeoid, Argyrochosma, and Cheilanthes clades were recovered from MP and ML analyses. The pellaeoid clade comprises four subclades that correspond to the following taxa: (1) P. sect. Pellaea (primarily); (2) P. sect. Platyloma, Paraceterach, and Paragymnopteris; (3) Astrolepis and Pellaea sagittata; and (4) Paragymnopteris marantae, P. sargentii, and Pellaea breweri. Subclade (1) is sister to (2); (1) and (2) are sister to (3), and (1), (2), and (3) are sister to (4). A morphological data matrix is also being developed. The phylogenetic hypothesis resulting from sampling of 17 species of American Cheilanthes in this study is used to test Reevesí morphology-based hypothesis of relationships among Cheilanthes subg. Physapteris. Several possible circumscriptions of pellaeoid ferns are discussed.
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1 - University of California, Berkeley, Department of Integrative Biology, University and Jepson Herbaria, 1001 Valley Life Sciences Bldg. #2465, Berkeley, California, 94720, USA
Cheilanthoid fern phylogeny
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, August 1st, 2006
Time: 11:00 AM