Multiclavula sp. (possibly M. lucida), on algae-covered road bank, Lost Coast, northern California, Feb 22, 2007. Also known as "scum lover".

• This is an unusual lichen unrelated to most others. While the alga and fungus appear to have an obligate relationship, there is no specialized thallus formed by the union. Also, while this is a true mushroom (Basidiomycetes), the vast majority of lichens are Ascomycetes, perhaps more popularly known as disk or cup fungi -- an entirely different division or phyllum. This isolated genus of lichens almost certainly evolved its symbiosis with algae independently of all other lichens.