THE GENUS Leveillula ON ASTERACEAE IN IRAN

Numerous newly collected and herbarium specimens belonging to the genus Leveillula on Asteraceae were examined using light microscopy. A total of six species including L. guilanensis, L. lactucae-serriolae, L. lactucarum, L. picridis, L. simonianii and L. taurica s.lat. were identified. It was found that, Lactuca spp. in Iran are infected at least with two different Leveillula species (L. lactucae-serriolae and L. lactucarum). Examination of several specimens belonging to L. taurica s.l. from Asteraceae showed that these taxa posses different conidial morphology. However, most of them are not differentiable from already described species. According to conidial morphology, L. taurica on Asteraceous plants can be categorized at least into three morphological groups. Specimens with lanceollate to more or less ellipsoid primary conidia. L. taurica on Carthamus, Crepis, Gundellia, Helianthus, annuus Taraxacum are categorized in this group. Second group includes specimens with more or less ellipsoid to ovoid primary conidia. L. taurica on Anthemis, Circium, Cousinia, Echinops spp. showed this type of conidia. Third group includes specimens with subcylindric primary conidia which are pointed at apex. Lanceolate primary conidia were also present in this group. Specimens on Acroptilon, Artemisia, Centurea, Launaea and Helianthus are categorized in this group. It is mentionable that sunflower (Helianthus annuus) in Iran is infected at least with two morphologically different groups of Leveillula.