FURTHER MYCOSPHAERELLA SPECIES ASSOCIATED WITH LEAF DISEASES OF EUCALYPTUS

Three new species of Mycosphaerella are described from diseased leaves of Eucalyptus growing in a species trial in south-eastern Australia: Mycosphaerella marksii sp. nov. was associated with circular to irregu lar, sometimes confluent lesions, bordered by a prominent red-brown ma rgin on several species of Eucalyptus; M. grandis sp. nov. and M aggre gata sp. nov. were associated with lesions confined to the leaf margin , extending from the tip almost back to the petiole, on leaves of E. g randis. It is likely that M grandis is a primary parasite and M aggreg ata a secondary invader. The species are distinguished mainly by their ascospore morphology and germination. Discrepancies between spore dim ensions recorded in this and a previous study are explained by differe nces in the stains used.