poorly known, might in fact belong to Lactifluus, which has a more tropical distribution than Lactarius. Several species have also been introduced with their host trees outside their native range, e.g. in South America, Southern Africa, Australia, and New Zealand. Ecology Lactarius belongs to a lineage of ectomycorrhiza obligate symbionts. As such, they are dependent on the occurrence of possible host plants. Confirmed habitats apart from temperate forests include arctic tundra and boreal forest, mediterranean maquis, tropical African shrubland, tropical Asian rainforest, mesoamerican tropical oak forests, and Australian Eucalyptus forests. While most species display a preference towards either broadleaf or coniferous hosts, some are more strictly associated with certain genera or species of plant hosts. A well-studied example is that of alders, which have several specialized Lactarius symbionts (e.g. L. alpinus, L. brunneohepaticus, L. lilacinus), some of which even evolved specificity to one of the Alnus subgenera. Other examples of specialized associations of Lactarius are with Cistus shrubs (L. cistophilus and L. tesquorum), beech (e.g. L. blennius), birches (e.g. L. pubescens), hazel (e.g. L. pyrogalus), oak (e.g. L. quietus), pines (e.g. L. deliciosus), or fir (e.g. L. deterrimus). For most tropical species, host plant range is poorly known, but species in tropical Africa seem to be rather generalist. Lactarius species are considered late-stage colonizers, that means, they are generally not present in early-colonizing vegetation, but establish in later phases of succession. However, species symbiotic with early colonizing trees, such as L. pubescens with birch, will rather occur in early stages. Several species have preferences regarding soil pH and humidity, which will determine the habitats in which they occur. Edibility Several Lactarius species are edible. L. deliciosus notably ranks among the most highly valued mushrooms in the Northern hemisphere, while opinions vary on the taste of other species, such as L. indigo or L. deterrimus. Several species are reported to be regularly collected for food in Russia, Tanzania and Hunan, China. Some Lactarius are considered toxic, for example L. turpis, which contains a mutagenic compound, or L. helvus. There are, however, no deadly poisonous mushrooms in the genus. Bitter or peppery species, for example L. torminosus, are generally not considered edible, at least raw, but are nevertheless consumed in some regions, e.g. in Finland. Some small, fragrant species, such as the "candy caps", are sometimes used as flavoring. L. deliciosus is one of the few ectomycorrhizal mushrooms that has been successfully