Trait evolution and nomenclatural adjustments in the Hawaiian lobeliads (Campanulaceae: Lobelioideae)

Abstract The 143 species of Hawaiian lobeliads constitute the largest adaptive radiation on any oceanic archipelago and comprise six recognized genera distributed across eight well‐supported clades. While molecular studies, including a recent study based on 633 nuclear loci, have supported a single colonization of the Hawaiian‐Emperor seamount chain, the Hawaiian species of Lobelia and the endemic genera Clermontia and Cyanea are not monophyletic. To maintain a natural classification and minimize taxonomic instability, we adopt a least‐change approach in providing a new generic circumscription of the Hawaiian lobeliads. This classification scheme is supported by ancestral state reconstruction of key morphological and ecological traits. We recognize six genera of Hawaiian lobeliads by resurrecting the genera Galeatella and Neowimmeria to rectify the non‐monophyly of Lobelia in Hawaii and subsuming Clermontia into Cyanea to render the latter monophyletic. This new classification expands the size of the largest plant genus on Hawaii, with 104 accepted species of Cyanea . To accommodate the morphological diversity of an expanded Cyanea , we propose a subgeneric classification that corresponds to the three major clades: Cyanea subg. Cyanea , Cy. subg. Clermontia , and Cy. subg. Delisseoideae . While we do not propose a sectional classification for the latter two subgenera, we do propose a preliminary sectional classification for Cy. subg. Cyanea using existing sectional names and well‐supported molecular clades. We highlight areas where species have been shown not to be exclusive lineages, and where attention in future phylogenetic and taxonomic studies may be warranted.