A new genus and species for Chloantheae (Lamiaceae)

Abstract. A molecular phylogeny of Chloantheae (Lamiaceae) based on a three-marker chloroplast and nuclear DNA dataset was used to test the monophyly of Lachnostachys Hook., Newcastelia F.Muell. and Physopsis Turcz. A clade consisting of at least one species from each of these genera was recovered separately from the ‘core’ Lachnostachys, Newcastelia and Physopsis clades. The members of this composite clade are here transferred to the new genus, Apatelantha T.C.Wilson & M.J.Henwood, which can be recognised by a combination of the base of the style being glabrous or with only non-glandular trichomes (glandular trichomes lacking), apex of corolla lobes (when present) acute to obtuse (not extending into an apical protrusion) and thin-textured (not distinctively thickened), pherophylls subtending three flowers, and anther connectives glabrous (sessile glands absent). A description of the new genus, together with new combinations for five species of Apatelantha, and amended descriptions of Lachnostachys, Newcastelia and Physopsis, are provided. A new species, Newcastelia clavipetala T.C.Wilson & Radunz, is described and illustrated. A taxonomic key to genera of Chloantheae, and keys to species of Lachnostachys, Newcastelia, Physopsis and Apatelantha are provided.