It is impossible to be completely certain of how many species of fungi occur in a particular locality. Fungi are not a well-studied group, and are easy to miss, as the length of time between the emergence of a fruiting body and its decay can be very short. The British Mycological Society
compiles a list of fungi species recorded throughout Britain, called the Fungal Records Database of Britain and Ireland. This database lists 2,289 species of fungi recorded in West Norfolk, and 3,262 species recorded in East Norfolk. If you are interested in the particular species occurring in your area, visit their website (click the link above). It is important to note that while the Fungal Records Database lists all species recorded, many of these species are microscopic - too small to identify with the naked eye - and are usually not listed in field guides.