Systematic position of Cyathocline Cass. (Asteraceae): evidences from molecular, cytological and morphological data

Abstract

Cyathocline, a small genus, has been treated as a member of subtribe Grangeinae of tribe Astereae (Asteraceae), but has been neglected in molecular phylogenetic analyses of Astereae. Plastid trnL-F and nuclear ribosomal DNA ITS sequences were used to carry out phylogenetic analyses of Cyathocline (represented by C. purpurea) through maximum parsimony and Bayesian analyses. In addition, its karyotype, morphology and micromorphology were also investigated. The results show that in our three phylogenetic trees, C. purpurea is deeply nested within the Blumea clade and/or the Inulinae clade, and is closest to Blumea balsamifera (Inuleae, Inulinae). C. purpurea is similar to Blumea in chromosome size bimodality and to Inulinae in one single large oxalate crystal within each cell of the cypsela epidermis, which, together with molecular evidences, suggests strongly that Cyathocline should be transferred from Astereae to Inuleae subtribe Inulinae. Although C. purpurea has many anomalous features, its most characters still are within a wide range of morphological variations of Blumea. DNA data and the karyotypic character support to merge C. purpurea into Blumea. As a result, the new combination Blumea purpurea (O. Kuntze) W.P. Li was made.