Lactarius pyrogalus, Fire Milk and the basic role of Mycorrhizal Fungi

 

Lactarius pyrogalus, growing below Hazel Corylus avellana. North Yorkshire

I found several troops of Firey Milkcap Lactarius pyrogalus growing in clusters of up to 15 in an area of broad-leaved woodland (Cock Mill Wood), along the Scarborough to Whitby disused railway line, known locally as the Cinder Track last week. This is a relatively common and widespread, autumn, mycorrhizal fungus, which usually grows in close association with Hazel. Although locally I tend to find it particularly in the forests of the northern Vale of Pickering and North York Moors and personally feel it becomes more scarce in East Yorkshire (although possibly this reflects my recording effort). 

Mycorrhizal fungi are symbiotic with their host plant, the term mycorrhiza referring to the fungus's role in the plants rhizosphere (root system), which it colonises. The plant makes organic sugars through photosynthesis and supplies them to the fungus, in return the fungus supplies the plant water and mineral nutrients notably phosphorous taken from the soil. This complex relationship is a reason certain plants struggle to survive in certain environments, and why planting new woodlands as mitigation for the loss of old woodland communities is not always the perfect solution.

Lactarius in latin means producing milk (lactating) and pyrogalus means fire milk. Lactarius pyrogalus is therefore a very appropriate name for this species of fungus, which exudes an extremely hot tasting white liquid when damaged. This can help with its identification (similar L.glyciosmus has a coconut smell and is almost always found beneath birch Betula spp.), although I tend not to use taste as a means of identifying fungi for obvious reasons. This species is considered inedible and some authors even suggest that it is poisonous.