Agrocybe rivulosa - Agrocybe rivulosa

Added to the British list in 2004 and has
since been found growing all over the country on piles of woodchips. It was first
described by Marijke Naute in 2003 from a site in the Netherlands,
growing on a pile of woodchips.

It can give the appearance of an Agaricus at a first look. The large
but thin ring on the stem and wrinkling of the cap as the mushrooms
mature are very characteristic.

Ref: Ken Burgess