In 1825, Elias Magnus Fries (1794–1878) predicted that the fungi would prove to be the largest group in the vegetable kingdom, analogous to the insects in the animal kingdom. Notwithstanding that fungi are not actually part of the plant kingdom, how right he has proved to be as the bicentenary of his prediction approaches. By the 1960s a few mycologists were speculating that there might be as many fungal as plant species, but almost no attempts to calculate estimates from the available data were made. As concern over the conservation of biodiversity in general grew in the subsequent decades, culminating in the signing of the Convention on Biological Diversity in 1992, more precise figures on species numbers of all kinds of organisms were required. A series of estimates of the number of fungi settled on figures ranging from 500,000 to almost 10 million species, with 1.5 to perhaps 5 million receiving most support among mycologists. A recent study even predicts up to a trillion species of microorganisms globally (1); how many of these are supposed to be fungi is not specified, but if this estimate holds true and only 1% of these were fungi, the global estimate of fungal diversity would be a thousand times higher than the current highest estimate of 10 million species.