Butterworth, Charles .
Phylogenetic Studies of the Coryphantha / Escobaria complex, Cactaceae.
Originally treated within Mammillaria, species of Coryphantha are small to medium globose cacti native to Mexico and the southern USA (a single species reaches Canada). Generic delimitation of Coryphantha is confusing with a number of genera such as Neobesseya, Escobaria Protomammillaria, Acharagma, Cumarinia, Ortegocactus, Neolloydia being variously sunk or split from Coryphantha depending upon the chosen taxonomic treatment.
The purpose of this presentation is to present preliminary results from a phylogenetic study of Coryphantha and related taxa. Chloroplast DNA sequence data was obtained from a large sampling of Coryphantha as well as related taxa such as Neolloydia, Ortegocactus, Pelecyphora, Mammilloydia, and Mammillaria. Outgroup taxa include Stenocactus, Ferocactus, and Leuchtenbergia. Chloroplast regions used in this study include rpl16 intron, psbA-trnH IGS, and trnL-trnF IGS. Phylogenetic reconstruction utilized maximum parsimony, parsimony ratchet, and Bayesian methods. Results indicate that Coryphantha sensu lato may not be monophyletic as currently circumscribed. For example, a narrow delimitation of Coryphantha likely renders Escobaria paraphyletic. Furthermore, Coryphantha macromeris subsp. macromeris and C. macromeris subsp. runyonii, both treated at genus level as Lepidocoryphantha by some authors may actually form a sister taxon to the core species of Mammillaria.
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1 - Desert Botanical Garden, Research, 1201 North Galvin Parkway, Phoenix, Arizona, 85008, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 554/Convention Center
Date: Wednesday, August 4th, 2010
Time: 4:00 PM