Fungi for which sexual reproduction has not been observed.

That is, the deuteromycete lack the structures which traditionally have been used to fungi. Thus, should sexual reproduction be observed – not all that uncommon an occurrence as fungi can be finicky in terms of the conditions under which they display their sexual forms – then the fungus can be assigned into, particularly, the zygomycetes, ascomycetes, or basidiomycetes.

Alternantively, can be employed to classify these otherwise barely classified fungi.

As with most taxa defined by the absence of something, the deuteromycete are a polyphyletic grouping. What particularly tends to be lacking are sexual spores, along with the structures that produce those spores, with reproduction occurring instead employing solely asexual spores.

The deuteromycete are also described as or .