Article

A molecular phylogenetic analysis using the Internal Transcribed Spacer 2 region (ITS 2) of nuclear ribosomal DNA was conducted to investigate the evolution of spines within Convolvulus and to test the monophyly of section Acanthocladi. A total of 49 species were included in the analysis, comprising 40 species of Convolvulus, Calystegia sepium and eight outgroup taxa. The results from parsimony analysis ofthe data showed that C. caput-medusae, a spined species from the Canary Islands, is more closely related to other Canarian endemic species of Convolvulus than to the spined C. trabutianus, from Morocco, with which it has been previously considered conspecific. Spines are shown to be homoplastic within Convolvulus and eight steps are required to optimise the character on the most parsimonious tree presented. Section Acanthocladi together with the other two sections recognised in the most recent revision of Convolvulus from Western Asia, the Mediterranean and Macaronesia are shown to be polyphyletic.