A morphological and molecular perspective of Trichoderma viride: is it one or two species?

Trichoderma viride are identified as having warted conidia. However, two morphologically distinct types of conidial warts, type I and type II, have been found. Because each type corresponds to a unique mitochondrial DNA pattern, it has been questioned whether T. viride comprises more than one species. Combined molecular data, morphology, physiology and colony characteristics distinguish type I and type II as different species. Type I corresponds to true T. viride, the anamorph of Hypocrea rufa. Type II represents a new species, T. asperellum, which is close to T. hamatum.