Parallel evoluton in lichen-forming fungi.

The asexual lichen-forming fungus Parmelia hypotropa has two common chemical races that differ sharply in biogeography and niche characteristics and appear to have been derived by morphologic parallelism from chemically identical races of the closely related Parmelia perforata, which is sexual. Among the lichen fungi many chemically variable asexual morphs, which conventional taxonomies treat as species, are probably polyphyletic like Parmelia hypotropa.

Habitat selection by chemically differentiated races of lichens.

The maritime European lichens of the aggregate species Ramalina siliquosa represent six chemical races. Where the races are sympatric they populate different habitats. Such intensive local ecological sorting of morphologically similar individuals accumulating different, highly specialized metabolic end products appears to be unknown in other plants.