The Significance of the Northern Andes for Lichens

Abstract

ABSTRACT Evaluation of the lichen flora of the Northern Andes must be based on a restricted number of better-known groups, probably less than 25% of the flora. This is because our knowledge of the taxonomy and distribution of lichens in the Tropics is still very incomplete. In the Andes, the groups with foliose and fruticose growth forms are particularly well represented; the crustose group seems less important. This is in contrast with the surrounding lowlands, where crustose is the dominant growth form. At higher taxonomic levels there is a resemblance in taxonomic composition with the cooler zones of the world, which disappears at the generic or sectional levels. A conspicuous morphological feature is the frequency of foliose lichens with linear, rhizinate, or ciliate lobes, probably an adaptation to very humid conditions. More than half of the species have a wide distribution throughout the Tropics or at least in the Neotropics. Among the more restricted taxa is a humid montane element. At the highest...