Truffulales

Whereas most Russulaceae (Russula, Lactarius and Lactifluus species) form regular mushrooms, others show an abbarant morphology. Rather, they form enclosed fruitbodies, which can be either with or without a stipe. These species are called truffle-like or sequestrate. Some grow completely hypogeous, others are partially or fully epigeous.

They are easily recognized by their enclosed shape, compressed and contorted white to cream-colored gills, and typically ornamented, amyloid spores. In case of milkcap-truffles, the fruiting bodies release a milky substance when cut. Some species are especially interesting, as they show both co-occuring ‘regular’ and truffle-like morphologies.

You can learn more on the genus from our booklet.

Almost 30 species of these truffle-like milkcaps or russulas have been described in Europe, but their distribution is poorly known due to their hidden lifestyle. They are possibly very rare, but more knowledge is needed to assess their ecology and Red List status.

Part of the Truffulales Project is to investigate the genomes of these species, to understand how this morphology has arisen several times in the evolutionary history of this family. To do so, we will focus on Russula messapica and Russula meridionalis. The latter species is always sequestrate, whereas the former forms both regular (var. messapica) and truffle-like morphologies (var. messapicoides).

Most European species of truffle-like Russulaceae occur in the Mediterranean region, whilst a few can be found in temperate and alpine habitats. The wishlist species occur mostly in Italy and Spain, where Russula meridionalis occurs under Quercus rotundifolia, and Russula messapica can be found under Quercus coccifera and Q. ilex, from Spring to Autumn. They both show a yellow-ochre pileus, that reacts red in contact with KOH in R. messapica. Figures and more detailed descriptions can be found in our booklet.

By reporting your findings, you will add to the knowledge of these species and your records will be important contributions to nature conservation.