on at least Russula crassotunicata. Fruitbodies of Lactifluus or Russula species otherwise hot-tasting and unpalatable are regarded as choice edibles in North America when infected by the "lobster mushroom" Hypomyces lactifluorum. Heterotrophic plants, including orchids or monotropoids, also parasitise ectomycorrhizal Russulaceae and their plant partners – see above, Other types of mycorrhiza. Threats and conservation As with most fungi, little information is available on the threat of extinction for Russulaceae species, and they have not been assessed in the International Union for the Conservation of Nature's Red List. However, national lists contain some species of Lactarius, Lactifluus and Russula, indicating that they have small populations and are endangered, e.g. in Great Britain, Switzerland, the Czech Republic, and New Zealand. Although data on Russulaceae themselves are scarce, more is known about the habitats they occur in, especially for the ectomycorrhizal species which depend on their host plants: Several of these habitats are affected by loss or degradation, such as peatlands, Mediterranean forests and scrub or tropical African dry woodland. Similarly, dead wood, the habitat of the corticioid Russulaceae, is rare in many exploited forests and needs special management. Recent studies have found some traditional Russulaceae species to comprise several cryptic species (see Systematics and taxonomy: Species diversity). This may imply that distribution range and population size for each of such distinct species are smaller than previously thought. Edibility Several species of Lactarius, Lactifluus and Russula are valued as excellent edible mushrooms. This is the case for example for the north temperate species Lactarius deliciosus, Lactifluus volemus, or Russula vesca, and other species are popular in other parts of the world, e.g. Lactarius indigo in Mexico, or Lactifluus edulis in tropical Africa. Some species, like Russula vesca, can even be eaten raw. The brittle texture of Russula fruitbodies makes them different from other mushrooms and is not appreciated by some. Several species have a hot to very acrid taste and can cause gastrointestinal symptoms. Despite this, such species are eaten in some regions, e.g. Lactarius torminosus in Finland or Russia. Often, they are parboiled or pickled to make them palatable, and sometimes, they are used as spice, for example Russula emetica in Eastern Europe. Some species are however truly poisonous: the East Asian and North American Russula subnigricans causes rhabdomyolysis and is potentially lethal, and Lactarius turpis from Eurasia contains a mutagenic substance. Cultivation of edible Russulaceae, as in other ectomycorrhizal fungi,