Isolation and Culture of Lichenicolous Fungi

Abstract

The lichenicolous fungi are characterised by their habit of growing on lichens. Hawksworth (1982) has estimated that as many as 1000 fungal species within 300 genera can be assigned to this group, and it is clear that they form a myriad of associations with lichens. Many attack living lichens and are obviously parasitic (mycoparasites) or pathogenic, but with levels of virulence that vary considerably. There are parasites that cause massive destruction of lichen tissues, but many cause little or no damage. Of these, some (called parasymbionts) appear to be lichen-forming fungi that share the photosynthate produced by another lichen’s captured photobiont cells. Still others are saprophytic and colonise only dead lichen tissues. Because lichens are now known to harbour many opportunistic fungi that are not restricted to lichens (e.g., Petrini et al. 1990), some investigators (Rambold and Triebel 1992) prefer to exclude saprophytes from the lichenicolous fungi. I will restrict my discussion here to those lichenicolous fungi that are obviously parasitic or pathogenic.