Hypomyces lactifluorum Lobster FungusThis widespread and common fungus attacks the fruitbodies of species of the mushrooms Lactarius and Russula. The mushroom fruitbodies develop abnormally and become brilliant orange or orange-red. Affected mushrooms are malformed and the gills either do not develop or are reduced to low ridges. The fruitbodies of the parasite appear as tiny dark dots (= perithecia) embedded in the host mushroom. The ascospores are shot off and often gather as a white to cream powder over the surface of the malformed mushroom. The perithecia of the parasite are immersed in a mixture of host and parasite tissue and this mixture is referred to as a pseudostroma (= false stroma). The true stroma is made up entirely of fungus tissue as in Dead Man's Fingers (=Xylaria polymorpha).