NEW SPECIES OR INTERESTING RECORDS OF FOLIICOLOUS LICHENS .1. TRICHOTHELIUM-ARGENTEUM (LICHENIZED ASCOMYCETES, TRICHOTHELIACEAE)

Trichothelium argenteum R. Lucking & L. I. Ferraro sp. nov. is disting uished by its very large perithecia with a well-developed, silvery whi te, basally black crown of setae, and by a non-radiate phycobiont. In young perithecia, the setae are confluent and form a characteristic, t wo-coloured disc-like expansion. Ascospores are 7-septate and bacillar . Trichothelium argenteum is known from a few populations in Costa Ric a, Ecuador, Brazil, Paraguay, and Argentina. (C) 1997 The British Lich en Society.