Abstract
Dasyphyllum Kunth is the most diverse genus of the South American subfamily Barnadesioideae (Asteraceae), comprising 33 species that occur in tropical Andes, Atlantic Forest, Caatinga, Cerrado, and Chaco. Based on distribution, variation in anther apical appendages, and leaf venation pattern, it has traditionally been divided into two subgenera, namely, Archidasyphyllum and Dasyphyllum. Further, based on involucre size and capitula arrangement, two sections have been recognized within subgenus Dasyphyllum: Macrocephala and Microcephala (=Dasyphyllum). Here, we report a phylogenetic analysis performed to test the monophyly of Dasyphyllum and its infrageneric classification based on molecular data from three non-coding regions (trnL-trnF, psbA-trnH, and ITS), using a broad taxonomic sampling of Dasyphyllum and representatives of all nine genera of Barnadesioideae. Moreover, we used a phylogenetic framework to investigate the evolution of the morphological characters traditionally used to recognize its infrageneric groups. Our results show that neither Dasyphyllum nor its infrageneric classification are currently monophyletic. Based on phylogenetic, morphological, and biogeographical evidence, we propose a new circumscription for Dasyphyllum, elevating subgenus Archidasyphyllum to generic rank and doing away with the infrageneric classification. Ancestral states reconstruction shows that the ancestor of Dasyphyllum probably had acrodromous leaf venation, bifid anther apical appendages, involucres up to 18 mm in length, and capitula arranged in synflorescence.
Highlights
Systematics of Asteraceae (Composite) has undergone major change over the last four decades, mainly due to the insights provided by molecular data
Phylogenetic analyses The incongruence length difference test (ILD) test did not indicate incongruences between the plastid and combined datasets (P > 0.05), allowing both to be used for further phylogenetic analyses
Based on the results of BP and Posterior probabilities (PP) (>80), we did not find any evidence of significant incongruence among the relationships that differed between the trees
Summary
Systematics of Asteraceae (Composite) has undergone major change over the last four decades, mainly due to the insights provided by molecular data. Phylogeny and circumscription of Dasyphyllum (Asteraceae: Barnadesioideae) based on molecular data with the recognition of a new genus, Archidasyphyllum. Subsequent phylogenetic studies indicated that Barnadesiinae is the sister group to the rest of the family (Bremer, 1987; Jansen et al, 1992); the subtribe was elevated to the rank of subfamily as Barnadesioideae (Bremer & Jansen, 1992). Its members are characterized by the presence of axillary spines arranged at the nodes, in pairs or in fascicles, and by the presence of unbranched three-celled hairs called “barnadesioid trichomes” on the corollas, cypselae, and pappus (Cabrera, 1959; Ezcurra, 1985; Bremer & Jansen, 1992; Bremer, 1994; Urtubey, 1999; Erbar & Leins, 2000; Ulloa, Jørgensen & Dillon, 2002; Stuessy, Urtubey & Gruenstaeudl, 2009)
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