Little is known about the distribution, requirements, and relationships of the byssaceous, mainly South American ascolichen genus Roccellinastrum, tentatively placed in the family Chrysotrichaceae by Follmann (1967), in the Micareaceae by Poelt (1974), in the Lecideaceae by Henssen, Vobis, and Renner (1982), and finally assigned by Hafellner (1984) to its own lecanoralean family, Roccellinastraceae. It comprises a series of highly specialized epiphytes, rarely recollected and scarcely represented in herbaria: R. epiphyllum Henss. & Vob., for instance, was previously known only from the type locality, a small forest relict on the ridge of the Altos de Talinay in subarid northern Chile. However, a second, isolated but abundant population of this foliicolous species has recently been found in a conifer wood on the heights of the Cordillera de Nahuelbuta in semihumid austral Chile about 800 km further south (fig. 1). Together with extensive new collections from the northern area, this gave rise to the comparative studies detailed below, the results of which might be of chorological, ecological, and taxonomical interest