Phylogenetic evidence for the generic circumscription of Cineraria L. (Asteraceae‐Senecioneae)

Abstract

AbstractPhylogenetic analyses of separate and combined plastid trnL‐trnF and nuclear ITS DNA sequences were used to investigate the delimitation of Cineraria with respect to five species previously included in Cineraria, its infrageneric structure, and to contribute to knowledge regarding its relationships in the tribe Senecioneae (Asteraceae). The molecular phylogenetic study (corroborated by morphological evidence) has resulted in a revised generic concept/circumscription for Cineraria with the removal of anomalous species from the genus and the recognition of two new genera: Bolandia and Oresbia. Bolandia comprises two South African species (B. argillacea, B. pedunculosa) previously included in Cineraria. The monotypic Oresbia heterocarpa (syn.: C. tomentosa) has unique morphological features and exhibits strongly incongruent placement with Kleinia galpinii versus Dendrosenecio kilimanjari in the trnL‐trnF and ITS datasets, respectively. Two other species previously placed in Cineraria are reinstated as Senecio cordifolius (syn.: C. mitellifolia) or reassigned as S. hederiformis (syn.: C. hederifolia) because of their close relationships to species currently placed in Senecio s.l. in a clade that also includes Pericallis. Cineraria now has a coherent morphological concept as plants with palmately veined leaves, radiate, calyculate capitula, obtuse/penicillate style apices and obovate, compressed cypselae with two distinct margins or wings and a substantial carpopodium. The species‐level comparisons within Cineraria show surprisingly limited amounts of DNA variation that nonetheless have striking points of incongruence between the trnL‐trnF and ITS datasets. Cineraria evidently experienced a rapid biogeographic and morphological diversification periodically punctuated by bouts of reticulate evolution. Investigations into relationships within the Senecioneae concur with previous reports that Cineraria is related to Pericallis and Dendrosenecio, and our increased taxonomic sampling identifies Bolandia as a putative sister‐genus to Cineraria.