Format: ORAL

Aarifah Jakoet1,2, J. Stephen Boatwright2, Ladislav Mucina3, Anthony R. Magee1,4

1South African National Biodiversity Institute, Cape Town, South Africa 2University of the Western Cape, Cape Town, South Africa 3Murdoch University, Perth, Australia 4University of Johannesburg, Johannesburg, South Africa

The genus Cotula L. (button daisies) historically comprises of ca. 50 species, distributed mostly in southern Africa with some species extending to or endemic to tropical Africa, Eurasia, the Americas, and Australia. The genus is closely related to the South American genus Soliva Ruiz Pav. and the largely Australasian genus Leptinella Cass. The latter two genera have been revised and are morphologically well-defined, whereas Cotula has never been revised in its entirety and currently has no synapomorphies to define the genus. Previous phylogenetic analyses of the genus Leptinella included a limited sampling of Cotula, and recovered both genera as non-monophyletic. We here present expanded phylogenetic analyses including 80% of the currently recognized Cotula species, using both nuclear (ITS) and plastid DNA regions (psbA-trnH and trnC-petN). Our analyses support the non-monophyly of Cotula, with Cotula mexicana (a South American endemic) embedded within Soliva, C. alpina (an Australian endemic) embedded within Leptinella, and Cotula sensu strictaa paraphyletic assemblage of four main clades. Together with morphological data, we here propose an expanded circumscription of Cotula to include Leptinella and Soliva (viz. Cotula sensu lato), comprising over 100 taxa with a nearly cosmopolitan distribution. Due to the size and complexity of this expanded concept, we also propose a new infrageneric classification based on both phylogenetic and morphological evidence. Cotula sensu lato is divided into two subgenera, Cotula subgenus Soliva (Ruiz. Pav.) Jakoet Magee and subgenus Cotula, and 21 sections. Extensive herbarium and field studies on Cotula sensu lato resulted in 136 taxa being recognized including four new species and seven species needing new combinations. A broad overview of the expanded phylogeny and the diversity of morphological characteristics, particularly fruit characters, within Cotula sensu lato is presented.