Taxonomy and distribution of three alien species of Senecio s.l. (Asteraceae) in Greece

Senecio angulatus and S. tamoides (Asteraceae), two species native to South Africa and naturalized in Greece are described and illustrated by photographs. A third species Roldana petasitis (syn. Senecio petasitis) native to Central America is similarly treated. The flowers resemble each other but the plants differ most clearly in their leaves. In S. angulatus the leaves are truncate or cuneate at base, entire or shallowly lobed while in S. tamoides the leaves are hastate or cordate at base and acutely angular-lobed. Roldana petasitis differs in having Petasites-like leaves, densely pubescent stems and involucres without supplementary phyllaries. It is a first report for the alien Greek flora. Distribution, ecological and habitat notes are provided for all three species together with a map of known occurrences in Greece.