A new Agrocybe on woodchips in northwestern Europe

In the scope of a revision of the genus Agrocybe for Flora agaricina neerlandica volume 6, a new species was discovered from heaps of woodchips in Rotterdam, the Netherlands, The species, Agrocybe rivulosa, spec. nov. is here described and is characterized by the strongly radially rugose cap, a large but thin ring and large spores of 11.5-12.0 x 7.0-8.0 μm on average. It belongs to subgen. Agrocybe sect. Agrocybe on account of the spores with a conspicuous and wide germ pore and the clavate to sphaeropedunculate cystidia. The species has been found on several localities in the (north)west of the Netherlands. Recently, the species has also been found in the eastern part of the Netherlands and in Luxembourg. Furthermore, a key is provided to the species on woodchips in the Netherlands and adjacent countries.