Monday, December 7, 2015
ascomycete fungus that grows on several species of mushrooms, they virtually always parasitize Lactarius (Milkys) and Russula species. I slowly forms a red crust like a lobster shell over the white underlying mushroom, eventually covering the host species, making it unidentifiable.
According to Wikipedia lobster mushrooms are widely consumed and commercially available, although some like Tom Volk raise doubts about eating found specimens. While they are usually safe, we can't tell if it is growing on a toxic species of mushroom. Lobster or not, it doesn't have much eye appeal to me as in its late stages it tends to distort the shape of the host.
There are lots of fungi that are parasitic on mushrooms, either on the fruiting body that we call a mushroom or in other cases on just the mycelium. It may kill the host or simply gain nutrition without significant damage. There is more at this link and Michael Kuo lists 25 of these mushroom parasites.