Agrocybe arvalis

Agrocybe arvalis is a small, brown-spored agaric with a brown cap. It is one of a number of species that grows on woodchip, often in large numbers. Agrocybe species are difficult to identify and many of them are quite similar to each other. Agrocybe arvalis can be confused with Agrocybe pediades and can only be reliably distinguished from it after microscopic investigation. The spores of Agrocybe arvalis are smaller and the cystidia that occur on the face of the gill (pleurocystidia) have finger-like projections. If specimens of Agrocybe arvalis are dug up carefully, then the rooting stem will be seen to arise from a hard, black mass (sclerotium), which is also an identification feature. There are very few records of Agrocybe arvalis from West Glamorgan, but it has appeared on woodchip in Crynant Community Forest.