Species of Pirottaea grow on plants that are taxonomically widely dispersed but seem mainly to belong to "advanced" families. About half the number of them inhabit Compositae and some of them are, furthermore, certainly collective. Other remarkable features are that Geranium silvaticum L. (and G. pratense L.) takes three species (P. geraniicola, P. paupercula and P. pilosissima) that represent three different lineages and that the inter se closely allied hosts Lamium album L. and L. maculatum L. take two species, P. lamii and P. saxonica respectively, that represent widely different lineages. It is much too