Ultrastructural observations on the rust fungus Puccinia malvacearum in Malva sylvestris ssp mauritiana

Our investigations show the structure of the intracellular mycelium of the rust fungus, Puccinia malvacearum, in leaves of Malva sylvestris ssp. mauri tiana. Some intracellular structures of the fungus pass through, others end in the host cells. Fungal infection leads to an increase in the number of mucilage cells in the leaves; but mucilage production does not stop fungal growth. In contrast, the fungus is able to invade mucilage cells without an y sign of fungal degradation.