Lactuca pumila (Asteraceae, Cichorieae) revisited—additional evidence for a phytogeographical link between SE Zagros and Hindu Kush

Abstract

Lactuca pumila, so far known only from a single gathering from E Afghanistan, is shown to occur also in the SE Zagros range, Kerman province, southeastern Iran. The new locality extends the range of the species about 1000 km south-westward and this disjunction further highlights the floristic link between the SE Zagros and the Hindu Kush as well as Central Asian mountains. Fruiting plants, so far not known of the species, confirm it as a member of the L. rosularis group, which includes four closely related species of rosette herbs confined to rock crevices in the montane to alpine zone of the Iranian–Afghan highlands. The relationships of the two disjunctly distributed populations and of the species is corroborated by a molecular phylogenetic analysis. A key to the species of the L. rosularis group, a full description, photographs of life plants, SEM images of achenes and a distribution map of L. pumila are provided, and the generic classification is discussed.