Generic circumscription of Cineraria L. (Senecioneae, Asteraceae) based on molecular evidence

Phylogenetic analyses of separate and combined plastid trnL-trnF and nuclear ITS DNA sequences were used to investigate (1) the position of Cineraria in the tribe Senecioneae (Asteraceae), (2) its delimitation with respect to five species previously included in Cineraria, and (3) its infrageneric structure. The results concur with previous reports that Cineraria is related to Pericallis, Dendrosenecio and Euryops, and our increased taxonomic sampling identifies Bolandia as the sister-genus to Cineraria. Bolandia comprises two South African species (B. argillacea and B. pedunculosa) previously included in Cineraria, and is characterised by pinnately veined, exauriculate leaves, solitary ecalyculate capitula on long peduncles, truncate style apices and heteromorphic fusiform cypselae with short, white mucilaginous hairs. 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 other Senecio species in a clade that also includes Pericallis. The fifth species is now treated as the monotypic Oresbia heterocarpa (syn: C. tomentosa) because of its unique morphological features and strongly incongruent placement with Kleinia galpinii versus Dendrosenecio kilimanjari in the trnL-trnF and ITS data-sets, respectively. 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 data-sets. Cineraria evidently experienced a rapid biogeographic and morphological diversification periodically punctuated by bouts of reticulate evolution. INTRODUCTION The genus Cineraria Cineraria L. (Senecioneae, Asteraceae) mostly comprises perennial herbs and subshrublets with heterogamous, radiate capitula, all with yellow florets. As suggested by the name (from ‘cinereus’ meaning ash-coloured), many of the species have grey leaves and stems due to a tomentose or cobwebby indumentum. The genus is distinguished mainly by its compressed cypselae (Hilliard, 1977), palmately veined leaves (Bremer, 1994) and yellow, radiate capitula (Figure 1a–c). Cineraria is essentially an African genus, ranging from the Cape Peninsula and mountains of South Africa, where it has its centre of diversity, along the eastern highlands of Africa to 2.2 Figure 1. Distinguishing features of Cineraria: (a ) C. ngwenyensis, an herbaceous perennial. Scale bar = 10 mm. (b) Palmate venation in leaf of C. austrotransvaalensis [Cron 19 (J)]. Scale bar = 5 mm. (c) Laterally compressed cypsela of C. vallis-pacis with distinct wings [Balkwill et al. 11802 (J)]. Scale bar = 325 μm. (d) Balusterform filament collars of Cineraria canescens [Pearson 5762 (BOL)]. Scale bar = 100 μm. (e) Obtuse disc style apex with sweeping hairs centrally and fringing apex of Cineraria aspera [Cron & Goodman 531 (J)]. Scale bar = 50 μm.