Format: ORAL

Pedro Costales-Maestre1, Seung-Chul Kim2, Marcial Escudero1, Jos A. Mejas1

1 Department of Plant Biology and Ecology, University of Seville, Apdo. 1095, 41080 Seville, Spain 2 Department of Biological Sciences, Sungkyunkwan University, 2066 Seobu-ro, Jangan-Gu, Suwon, Korea 16419

Functional traits are measurable properties of individuals that determine their basic performance model and role in the communities. The assignment of functional traits allows us to configure the ecological and evolutionary attributes of the individuals conforming a taxon and detect divergences associated to speciation processes. Furthermore, the analysis provides a framework for selecting appropriate operational criteria under the approach of Integrative Taxonomy. Sonchus asper (L.) Hill is a relevant case in this sense. It is considered a cosmopolitan self-fertilized annual weed with small, unattractive flower heads. However, the variability within the species current circumscription revealed the presence of differentiated morphotypes in the Mediterranean, characterized by these functional traits: a) large flower heads, which denotes xenogamous sexual systems; and b) variability in growth habit, from the common annual cycle to creeping rhizomatous life form. A taxonomic revision under a multidisciplinary approach is consistently presented here. Morphologic examination revealed that flowers, leaves, underground parts and fruit traits are important to discriminate between morphotypes. Phylogenetic analysis revealed two separate clades: 1) autogamous with small flower heads; and 2) xenogamous with large flower heads, which includes three monophyletic and one paraphyletic groups. Chromosome number is conserved among morphotypes, with slight differences in chromosome morphology. Post-mating isolation barriers appear to be weak. Therefore, the analysis of ecological and distribution patterns is crucial to understand speciation processes. Our results support these conclusions: 1) The limitation of the name S. asper (L.) Hill to autogamous annual forms. 2) The reinstatement of three taxa described in the 19th-century: S. nymanii, a rhizomatous creeping Sicilian endemism; S. glaucescens subsp. glaucescens, a biennial south-eastern French coast endemism; and S. glaucescens subsp. graecus, an annual widely distributed throughout central and eastern Mediterranean. 3) The existence of a different perennial taxon from mountainous areas of North Africa.