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1 May 2014 A Molecular Phylogeny and Generic Classification of Asphodelaceae Subfamily Alooideae: A Final Resolution of the Prickly Issue of Polyphyly in the Alooids?
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Abstract

Phylogenetic analysis of plastid (rbcLa, matK, trnH-psbA and the trnL intron) and nuclear (ITS1) sequence datasets in a wide sampling of species of Asphodelaceae: Alooideae provides a generally well-resolved phylogeny. Among traditionally accepted genera only Astroloba and Gasteria are supported as monophyletic. Species of Haworthia are distributed among three clades corresponding to the current subgenera. Aloe s. l. (including Chortolirion) segregates into six, well-supported clades corresponding respectively to sections Dracoaloe (= Aloidendron), Kumara Haemanthifoliae, Macrifoliae, Aristatae, Serrulatae, and the remainder of the genus. The first three clades are retrieved as early branching lineages, whereas A. sects. Aristatae and Serrulatae are strongly supported as members of a clade including Astroloba Haworthia subg. Robustipedunculatae. We examine possible options for recircumscribing the genera of Alooideae as reciprocally monophyletic entities. Although morphological and molecular data are consistent with expansion of Aloe to include all members of Alooideae, we accept and implement an alternative option maintaining historical usage in the group as far as possible. Astroloba and Gasteria are retained as currently circumscribed; Haworthia is restricted to H. subg. Haworthia; the genus Tulista is accepted for members of H. subg. Robustipedunculatae, with the new combination T. minima; and H. subg. Hexangulares is treated as the genus Haworthiopsis with the new combinations H. koelmaniorum, H. pungens, and H. tessellata. The genus Aloe is restricted to the clade comprising the ‘true aloes’, with Aloidendron, Aloiampelos, and Kumara accepted as segregates, the latter broadened to include A. haemanthifolia as K. haemanthifolia. Aloe aristata is segregated in the monotypic genus Aristaloe as A. aristata and Aloe sect. Serrulatae is treated as the new genus Gonialoe with the species G. dinteri, G. sladeniana, and G. variegata.

© Copyright 2014 by the American Society of Plant Taxonomists
John Manning, James S. Boatwright, Barnabas H. Daru, Olivier Maurin, and Michelle van der Bank "A Molecular Phylogeny and Generic Classification of Asphodelaceae Subfamily Alooideae: A Final Resolution of the Prickly Issue of Polyphyly in the Alooids?," Systematic Botany 39(1), (1 May 2014). https://doi.org/10.1600/036364414X678044
Published: 1 May 2014
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