Simmons, Mark P. , McKenna, Miles J. , Archer, Robert H. , Bacon, Christine D. , Lombardi, Julio A. .
Delimitation of the Segregate Genera of Maytenus sensu lato (Celastraceae) Based on Morphological and Molecular Characters.
Maytenus sensu lato (including Gymnosporia) is large genus of about 300 species that is widely distributed in the tropics and subtropics of both the Old and New Worlds. Maytenus is a morphologically diverse genus of trees or shrubs with alternate leaves, axillary inflorescences, bisexual or unisexual flowers on monoecious or dioecious plants, 4- or 5-merous flowers, intrastaminal disks, 2- or 3-locular ovaries, one or two erect ovules per locule, loculicidally dehiscent capsules, and arils that partially or completely envelop the seeds. The delimitation of Maytenus has been extensively debated for over 100 years. Despite the segregation of Celastrus and Gymnosporia from Maytenus, Maytenus sensu stricto remains a heterogeneous, polyphyletic group. To delimit natural segregate genera we increased taxon sampling for the pertinent lineages and generated sequences from two nuclear loci (ITS and 26S rDNA) and two plastid loci (matK and trnL-F). These sequences were analyzed together with morphological characters and sequences generated in previous studies. Both Moya and Tricerma were found to be nested within the New World Maytenus and are recognized as synonyms of Maytenus sensu stricto. In contrast, the three New World species of Gymnosporia are recognized as a distinct genus that is closely related to Gyminda. Putterlickia is nested within Gymnosporia and is synonymized with that genus. Existing intrageneric classifications of Gymnosporia and Maytenus sensu stricto were not supported. Austral-Pacific Maytenus are transferred to Denhamia. African Maytenus are treated as Scytophyllum.Â Gymnosporia are inferred to have had an African origin followed by a single successful radiation in southeast Asia and the Austral-Pacific.
Log in to add this item to your schedule
1 - Colorado State University, Department of Biology and Program in Molecular Plant Biology, Fort Collins, Colorado, 80523-1878, USA
2 - Colorado State University, Department of Biology, Fort Collins, CO, 80523-1878, USA
3 - South African National Biodiversity Institute, National Herbarium, Private Bag X101, Pretoria, 001, Republic of South Africa
4 - Instituto de Biociências de Rio Claro, Departamento de Botânica, Universidade Estadual Paulista - UNESP, São Paulo, Brazil
Presentation Type: Oral Paper:Papers for Sections
Location: Ballroom B/Convention Center
Date: Monday, August 2nd, 2010
Time: 1:00 PM