Phylogeny of Gardenieae (Rubiaceae) based on chloroplast DNA sequences from the rps16 intron and trnL(UAA)‐F(GAA) intergenic spacer

Abstract

Chloroplast DNA (cpDNA) sequences of the rps16 intron and the trnL (UAA)‐F(GAA) intergenic spacer were obtained from 59 species, to evaluate phylogenetic relationships among members of the Gardenieae, Rubiaceae. The results indicate that Gardenieae is polyphyletic and that genera included in the subtribe Diplosporinae should be transferred to the Coffeeae and Octotropideae. The Octotropideae tribe may also be polyphyletic. It is also demonstrated that the tribe Pavetteae is polyphyletic. In addition, the present data support a basal position for the disputed genus Bertiera within the Coffeeae clade. Of the informal groups proposed by Robbrecht & Puff within the Gardenieae, the Alibertia group is strongly supported, and is estimated to also include Ibetralia, Genipa aff. williamsii, and one undescribed taxon. However, Genipa americana was not part of this clade suggesting that Genipa is polyphyletic. The Tetrad group is not supported, and character optimisations suggest that pollen released in tetrads may have arisen three times. Most of these genera appear in the same clade as the three neotropical genera Sphinctanthus, Rosenbergiodendron, and Tocoyena, all of which bear pollen in monads. Atractogyne, Mitriostigma, and Oxyanthus form the second group with pollen in tetrads, whereas Gardenia is embedded in a third group. Massularia, with polyads, occurs either singly on a large polytomy or at the base of the Atractocarpus‐Porterandia‐Trukia clade.