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The primitive Epidendroideae (Orchidaceae): Phylogeny, character evolution and the systematics of Psilochilus (Triphoreae)

Rothacker, Erik Paul
http://rave.ohiolink.edu/etdc/view?acc_num=osu1181830674

Abstract Details

2007, Doctor of Philosophy, Ohio State University, Evolution, Ecology, and Organismal Biology.
Considering the significance of the basal Epidendroideae in understanding patterns of morphological evolution within the subfamily, it is surprising that a robust hypothesis of historical relationships has not been presented for these orchids. This is the first study to improve both taxon and character sampling. The phylogenetic study of the basal Epidendroideae consisted of two components. A molecular phylogeny using three loci representing each of the plant genomes including gap characters is presented for the basal Epidendroideae. The results of the morphological analysis results support many of the traditional views of tribal composition, but do not fully resolve relationships among many of the tribes. A robust hypothesis is presented based on the results of a total evidence analysis (TEA) using three molecular loci, gap characters and morphology. Palmorchis is sister to Neottieae, followed successively by Triphoreae sister to Epipogium, then Sobralieae. Tropidieae is sister to the advanced Epidendroideae, and this sister to Nervilieae and Gastrodieae. Diceratostele gabonensis groups within this clade. Morphology is studied mapped onto the TEA and discussed. As part of the study of the basal Epidendroideae, a monograph of the orchid genus Psilochilus (Triphoreae) was prepared in order to better understand the natural variation within the genus. Based on this work, there are seven species recognized, of which one is a newly described species, Psilochilus ecuadoriensis, from lowlands of western Ecuador. A molecular phylogenetic study of the genus, representing five of the seven species, was performed using the plastid trn L-F intergenic spacer. Psilochilus physurifolius is at the base of the genus. Psilochilus modestus and P. macrophyllus form a clade and this sister to P. mollis and P. ecuadoriensis. Morphological characters that were useful for species delimitations were mapped onto this tree. Psilochilus is monophyletic based on sequence data, and is supported by the presence of two calli on the labellum and petiolate leaves.
John Freudenstein (Advisor)
470 p.
Biology, Botany
character evolution; Epidendroideae; morphology; Psilochilus; Triphoreae; phylogeny; Orchidaceae; systematics; total evidence

Recommended Citations

Citations

  • Rothacker, E. P. (2007). The primitive Epidendroideae (Orchidaceae): Phylogeny, character evolution and the systematics of Psilochilus (Triphoreae) [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1181830674

    APA Style (7th edition)

  • Rothacker, Erik. The primitive Epidendroideae (Orchidaceae): Phylogeny, character evolution and the systematics of Psilochilus (Triphoreae). 2007. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1181830674.

    MLA Style (8th edition)

  • Rothacker, Erik. "The primitive Epidendroideae (Orchidaceae): Phylogeny, character evolution and the systematics of Psilochilus (Triphoreae)." Doctoral dissertation, Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1181830674

    Chicago Manual of Style (17th edition)

osu1181830674
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This open access ETD is published by The Ohio State University and OhioLINK.