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

Tribe Buddlejeae is a widely distributed group with ca. 108 species comprising five commonly accepted genera, Buddleja, Chilianthus, Nicodemia, Gomphostigma,and Emorya. Conflicting generic- and infrageneric-level classification systems based on morphology attest to a need to evaluate relationships and trait evolution in a phylogenetic framework. The majority of thespecies diversity and distributional area of the tribe is encompassed by Buddleja, which includes more than 90 species distributed in Africa, Asia, North America, and South America.We present here the first molecular phylogenetic analysis of the tribe Buddlejeae with broadly representative taxonomic sampling, including members of all recognized generaand extensive sampling of species in the large genus Buddleja from across its range. We use sequence data from thenuclear ribosomal locus ETS, three low-copy nuclear genes from thepentatricopeptide repeat gene family (At1G31430/PPR24, At4G30825/PPR97,At5G39980/PPR123), and three non-coding plastid regions (rpoA, trnD-trnT, trnS-trnfM).Nicodemia and related genera, Chilianthus, Emorya and Gomphostigma are included in the new circunscription of Buddleja.American Buddleja taxa form a clade with high support. The species grouped under the Cordatae series by Norman form the basis of this American clade. The Stachyoides and Thyrsoides series would be the most recently diversified. The results contain biogeographic implications, indicating a direction of colonization from North America to South America. Asian taxa also form a clade. African taxa are basal. These results suggest a South African origin for the genus Buddleja, in a scenario where Arabic Madagascar and Asia could have been part of the route dispersal.