Five facts that show we know too little about fungi, and their harmful effects on human health

Fungi are ubiquitous in nature. No one really knows how many species of fungi there are – one estimate is between 2.2m and 3.8m – and of those species only 120,000 have been documented. Fungi and moulds encompass a dizzying range of physical forms and attributes, living in both temperate environments and in extremes of hot, cold, or in the depths of the ocean.

Most play a vital but unseen role breaking down plant matter and redistributing nutrients through the soil. Some are good to eat – yeasts, for example, are integral to creating bread, beer and other foodstuffs that have shaped societies and cultures over many centuries. But many others are toxic, for example the poisonous death cap.