A taxonomic revision of Calea subgenus Meyeria (Asteraceae, Neurolaeneae), endemic to the Southeast and South Brazilian open vegetation

Meyeria Baker is endemic to southeastern and southern Brazil, where it occurs in open vegetation such as grasslands, savannas, and rock outcrops. This subgenus includes eight species and one hybrid, and its monophyly has recently been supported by molecular data. The aim of this study is to provide a taxonomic revision of the subgenus.

Protologues and herbarium specimens were studied and together with fieldwork, these efforts resulted in more than 1300 specimens analyzed in detail. Morphological descriptions of the subgenus and its subordinate taxa are provided, including the description of a new nothospecies C. × malmeana V.R.Bueno & G.Heiden nothosp. nov. The subgenus currently comprises eight species and two nothospecies, and is characterized by having a shrubby habit, ovate leaf blade, two series of foliaceous phyllaries, radiate capitula, and pappus of 8–15 scales.

In addition, we provide data on distribution and habitat, informal conservation status, phenology, taxonomic notes, distribution maps, selected examined material, field images, and illustrations for the eight species and two nothospecies. This revision contributes to a better understanding of Calea and represents an important step forward by performing a detailed revision of an infrageneric group after classification based on a phylogenetic hypothesis.