Date of Award
Master of Science
Ecology, Evolution, and Organismal Biology
Ecology and Evolutionary Biology
Lynn G. Clark
Dennis V. Lavrov
Robert S. Wallace
Rhipidocladum, a genus of about 18 species divided among three sections, is classified within the neotropical woody bamboo subtribe Arthrostylidiinae (Poaceae: Bambusoideae: Bambuseae). Morphology and molecular analyses support the monophyly of the subtribe, but internal relationships remain uncertain. Our objectives are: (1) test the monophyly of Rhipidocladum using molecular phylogenetics, (2) examine evolution of morphological characters using our phylogenetic hypothesis and (3) revise the taxonomy of the genus. We generated a maximum parsimony (MP) phylogeny of 36 taxa (30 representing 11 of the 13 Arthrostylidiinae genera and 6 outgroup taxa) using sequence data from both coding (ndhF) and non-coding (trnD-trnT, trnC-rpoB, rps16-trnQ, trnT-trnL) chloroplast DNA regions. Our results support the monophyly of the subtribe and reinforce the hypothesized multiple origins of apsidate (fan-like) branching, a character shared by Actinocladum, Merostachys and all sections of Rhipidocladum. They also reveal, for the first time, an Arthrostylidium + Rhipidocladum + Elytrostachys clade. Rhipidocladum, however, is paraphyletic, with R. section Didymogonyx forming a polytomy with Elytrostachys and Arthrostylidium + R. section Rhipidocladum + R. section Racemiflorum. In light of this new molecular evidence, we elevate R. section Didymogonyx to generic status, and distinguish it based on gross morphology and foliar micromorphology. The relationship between the other two sections of Rhipidocladum and the allied genus Arthrostylidium remains unresolved. We conclude by revising the taxonomy of the genus: submerging one species, describing three new species, and transferring one species into Rhipidocladum. Please note that this work is not intended as effective publication of new names or combinations.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Christopher Dean Tyrrell
Tyrrell, Christopher Dean, "Systematics of the neotropical woody bamboo genus Rhipidocladum (Poaceae: Bambusoideae)" (2008). Retrospective Theses and Dissertations. 15419.