at least as many yet to be documented. Over 100 species belonging to 52 genera have been reported from China, which has emerged as one of the worldwide hotspots of Boletaceae diversity. The family is also reasonably well-represented in the Mediterranean region, where many rare or range-restricted species can be found. Ecology As heterotrophic organisms, the majority Boletaceae species are symbiotic, and form mutually beneficial ectomycorrhizal associations with various trees and shrubs. However, a number of ancestral species in genera Buchwaldoboletus and Pseudoboletus, are saprotrophic or parasitic. Evidence suggests that some, if not all, species of Chalciporus might also have a mycoparasitic interaction with other fungi. The exact trophic status of some South American and African boletes, such as species of Phylloboletellus, is nonetheless not yet fully clarified, as fruit bodies are often found without the presence of ectomycorrhizal vegetation. Most frequently associated tree-hosts are members of the Fagaceae, particularly oak (Quercus), beech (Fagus) and chestnut (Castanea). Fewer species are associated with conifers, mostly spruce (Picea) and fir (Abies). In the Mediterranean region, most boletes are strongly associated with evergreen oaks, particularly members of the "Ilex" group, such as the holm oak (Quercus ilex), the kermes oak (Q. coccifera), or the golden oak (Q. alnifolia). Some boletes are also known to grow in association with Cistaceae shrubs, mainly Cistus and Helianthemum, and at least one species (Leccinellum corsicum) is exclusively associated with rockrose. Most boletes are sensitive to cold and fruit during warm spells in the summer and early months of the autumn, while some have very specific preferences with regards to substrate. For instance, the highly sought after Boletus aereus is mostly found on acidic soils, whereas the poisonous Rubroboletus satanas is predominantly calciphilous and mostly occurs on chalk. Other species, such as Hemileccinum impolitum or Leccinellum lepidum, are indifferent to the substrate and frequently occur on both calcareous and acidic soil. Conservation A number of Boletaceae species are considered rare, vulnerable or endangered, and some have been included in regional or national Red Lists. Rubroboletus dupainii is listed among the 33 threatened fungi of Europe, as part of Appendix I of the Bern Convention. Rubroboletus rhodoxanthus is considered extinct in England and critically endangered in the Czech Republic. Also critically endangered in the Czech Republic are Aureoboletus moravicus, Buchwaldoboletus sphaerocephalus, Butyriboletus fuscoroseus, Imperator rhodopurpureus, Leccinum roseotinctum and Rubroboletus rubrosanguineus. Eleven species of Boletaceae, Boletus aereus, Boletus pinophilus, Butyriboletus