Tricholoma psammopus

English Name: Larch Knight (other scientific names include Agaricus psammopus)

This tawny to ochraceous brown species often gives pause for thought when collected as for some reason it never looks quite like a Tricholoma. It is probably often thrown away or misidentified when for this reason. However, if you follow the key to genus, it comes out at Tricholoma quite easily with white, non-amyloid spores, no cystidia and emarginate gills (curve up towards the cap at the stem but still attached to the stem. See bottom photo) that can sometimes appear almost free (not attached to the stem). More information on gill attachment types.

Although often quite small, the cap can grow up to 8cm across and is generally rather hemispherical or convex in shape. The stipe (stem) is often whitish at the top with a distinct change in the lower part, which is usually a darker red brown. There are no veil remains.

The species is ectomycorrhizal on conifer with a particular preference for larch. More information about some of these terms and fungal lifestyles.

Fruiting:

In Scotland this species starts to appear in July (3 records), peaks in August (35 records) and tails off into October (4 records) with no records so far out with this time period.

Habitat:

Tricholoma psammopus almost always associates with larch (Larix) in the UK although Funga Nordica suggests that it will occasionally grow with pine (Pinus) or fir (Abies) and there is one record on the FRDBI that gives Pinus sylvestris as the host. The edge of mature larch plantations is the obvious place to look but it will also occur with standard trees that have been grown as a part of park or policy landscape.

Distribution:

The Checklist gives the distribution as ‘occasional’ everywhere but in general widespread. The total number of sites for this species on the Fungal Records Database of Britain and Ireland (FRDBI) is 143 with 78 of these from Scotland. Here's a map of the 10km distribution up to 2007. Can you add some new locations?

By Liz Holden, 2012

Tricholoma psammopus (Larch Knight) showing darker red brown at base of stipe.

Tricholoma psammopus (Larch Knight)

Tricholoma psammopus (Larch Knight) showing emarginate gills typical of the genus.

All photos Liz Holden