Systematics of the tribe Buddlejeae (Scrophulariaceae): phylogenetic relationships, biogeography, and morphological evolution

CHAU JOHN; O'LEARY, NATALY; OLMSTEAD, RICHARD

Boise, Idaho

Congreso; BOTANY 2014; 2014

ASPT

Buddleja belongs in the predominantly southern hemisphere Scrophulariaceae s.s., it is the largest genus of tribe Buddlejeae with nearly 100 species and with the broadest distribution, being found in tropical, subtropical, and temperate zones of Africa, America, and Asia, but with the greatest species diversity in America. Buddleja is closely related to the other 4 genera from tribe Buddlejeae: Chilianthus, Gomphostigma, Emorya and Nicodemia. Molecular phylogenetic studies base on nearly 150 taxa, employing nuclear ETS and two PPR loci, as well as three chloroplast loci (trn D-T, trnS-fm, rpoA) evidence monophyly of genus Buddleja, including under it genera  Nicodemia, Chilianthus, Emorya and Gomphostigma. American taxa form a highly supported clade. American species from Norman?s ser. Cordatae seem to form the basal grade within this american clade; the series Stachyoides and Thyrsoides are the more recently diversificated. This encloses biogegraphic implications, indicating a direction of colonization from North America to South America, given series Cordatae is primarily north American and both series Stachyoides and Thyrsoides are south American. Apart from that, Asian taxa also form a clade, and African species are the most basal ones, suggesting a South African origin of genus Buddelja, where Malagasy and Arabian Asia could be part of the dispersion route.