Species of the Month - September 2017

Amethyst Deceiver

Laccaria amethystina
 

The Amethyst Deceiver is a common woodland mushroom characterised by the purple cap, gills and stem.  The cap is normally about 2-4 cm across, with the outer part often lined due to the gills showing through the cap.  It grows with a wide variety of trees, both broadleaved and coniferous, but the most frequent is beech, as in the photo above.  The caps can be hard to spot among beech leaf litter but are more conspicuous in bare, mossy or grassy soil.

In dry weather the caps turn white, as in this photo by Jan Hamilton.  The stems are very tough and often twisted.
 

The stem has a covering of loose white fibres, especially when young.  This photo by Sallie Jack shows the widely-spaced gills with shorter gills between them at the cap edge.  These rather wavy and waxy gills help to distinguish the Amethyst Deceiver from other purple mushrooms.  The spores are white; this can often be seen on the gills of mature specimens, or can be detected by leaving the cap overnight on a smooth surface to give a spore print.

The main confusion species is Cortinarius violaceus but that is a much larger mushroom with a chunky bulbous stem, a rough scaly cap and brown spores.  It is very rare.  Other mushrooms with purple cap and/or stem don't generally have purple gills as well, or if they do the gills are spaced close together.
 

The cap also has a covering of white fibres when young, but these soon disappear to leave a smooth or minutely scaly surface.
 

These were growing under Spruce on Lismore, photo by Teenie Wilson.  The whole mushroom becomes brown as it gets older, eventually losing every trace of purple.  The stems are often the first part to turn brown.

Please send in your Amethyst Deceiver sightings using the form below, or email sightings@lnhg.org.uk with the details if you prefer.  If you are not sure of the identity of your mushroom, please send a photo to sightings@lnhg.org.uk, or put one on the LNHG Facebook page.