Phylogenetics and Taxonomy of the Tribe Merianieae

Abstract

The tribe Merianieae is a strictly Neotropical group with ca. 300 species in eight genera: Adelobotrys, Axinaea, Centronia, Graffenrieda, Macrocentrum, Maguireanthus, Meriania, and Salpinga. The tribe is characterized by diplostemonous flowers, anthers with simple to complex dorsal connective appendages, lacking ventral appendages, short or absent pedoconnectives, superior or partly superior ovaries, and capsular fruits. The majority of species have terminal inflorescences, pyramidal and cuneate seeds, and subulate anther thecae, but there is a remarkable amount of variation in habit, calyx, and androecial morphology. Phylogenetic analyses have shown that Salpinga is the only monophyletic genus as currently defined, but most clades are well supported by morphology and geography. Taxonomic realignments should wait until the tribe is better sampled with a higher number of species and loci.