Acarospora orcuttii (Acarosporaceae), a rare terricolous lichen from southern California

Abstract

The terricolous Acarospora orcuttii is described from three historical collections from San Diego in 1883 and 1884 by C.R. Orcutt in the Farlow Herbarium. The species looks similar to A. fuscescens, but differs in the absence of gyrophoric acid, thinner paraphyses as well as several other characters. The species may be extinct. Terricolous lichen habitats are rare and threatened throughout coastal southern California. It is hoped some remaining populations may be discovered.