Leaf colonizing lichens: their diversity, ecology and future prospects

Abstract

Phyllosphere - the world on a leaf, contains an interesting symbiotic association of a photobiont and a mycobiont, called foliicolous lichens. These are widely distributed in wet or moist, highly humid or foggy tropical and subtropical forests, on leaf surfaces of plants called phorophytes and are characterized by low endemism and short life cycle, corresponding to the leaf lifespan. Species diversity of foliicolous lichens is remarkable, with a single phorophyte individual supporting 65-84, and a single leaf as many as 81 lichen species. They exhibit marked structural diversity and ecomorphological adaptations to light conditions, and are potentially sound indicators of environmental conditions. In India, so far only 116 species of these lichens have been recorded, mainly from the Andaman and Nicobar Islands, Palni and Nilgiri Hills, and the Northeast. This article highlights conspicuous lack of information on the ecology and life history of these interesting organisms.