Some new lichen species from Sri Lanka, with a key to the genus <I>Heterodermia</I> in Sri Lanka

The following new species are decribed from Sri Lanka: Heterodermia rubrotricha which is similar to Heterodermia leucomela but with red, K + purple pigment on the cilia. Malmidea sanguineostigma, which is similar to Malmidea chrysostigma but has red anthraquinone in the thallus medulla, yellow xantholepinone in the excipulum medulla and smaller ascospores. Protoparmelia megalosporoides which is unique in the genus by the lecideine apothecia resembling those of Megalospora. A key to the species of Heterodermia in Sri Lanka is provided, applying a chemically and morphologically strict species concept.