Introduction

The numbers of known fungi are vast in comparison with the numbers in other groups of microorganisms used in biotechnological and other industries. Around 64 200 species (including yeasts) are currently known (Hawksworth, Sutton & Ainsworth, 1983), with new species being described at the rate of about 1500 each year. The number being described is limited only by the available mycologists, and the actual number of fungal species in the world may well exceed 250 000.

While only 7000 of these species have yet been grown successfully in pure culture, fungi hitherto known only on a specific host or natural substratum continue to be encountered or cultured for the first time; with appropriate techniques it is clear that many more species could also be cultured. This, together with the appreciation that many of the new species discovered each year are grown in pure culture, is exciting to the biotechnologist in search of strains with significant novel properties.

With such large numbers of fungal species, and a dispersed systematic literature growing at the rate of around 1200 titles each year (Bibliography of Systematic Mycology 1943 on), the extent to which a nonspecialist can expect to identify isolates to species with confidence is limited. However, some culture collections have specialists in identification on their staff or are associated with scientists able to assist in their identification of isolates and further information on collections providing these services can be obtained by reference to Chapter 1.

Considerable care is needed in identification if confusion is not to be created in the commercial and scientific literature. There are many cases of elegant biochemical, chemical, cytological or ultrastructural studies which have used incorrectly identified material.