How many different species of mushroom are there all over the world?

The estimated number of mushroom species worldwide varies widely, with different sources providing different ranges. Some sources suggest that there may be as many as 140,000 mushroom species, while others estimate that the true number could be closer to 3.8 million. However, it is important to note that these numbers include both described and undescribed species, and the number of described species is significantly lower. According to the Index Fungorum, a global database of fungi, there are currently around 120,000 described species of mushrooms. As scientific research and exploration continue, new mushroom species are being discovered and described regularly, contributing to the ever-growing diversity of known fungal species.