A revision of the genus Trichoderma. II. Infrageneric classification

Abstract

The genus Trichoderma Pers.:Fr. is defined to include anamorphs of Hypocrea, previously placed in Gliocladium and Verticillium, having elongate phialides and irregularly branched conidiophores. A sectional classification is proposed for Trichoderma recognizing the following five sections: section Trichoderma, section Longibrachiatum Bissett, section Saturnisporum Doi et al., section Pachybasium (Sacc.) stat.nov., and section Hypocreanum sect.nov. Trichoderma lactea sp.nov. is described, typifying section Hypocreanum. The species in section Trichoderma have narrow and flexuous conidiophores and branches, with branches and phialides uncrowded, frequently paired, and seldom with more than three elements in a whorl. Section Pachybasium includes species with highly ramified conidiophores that are often aggregated into compact fascicles or pustules and with relatively short, broad branches bearing inflated phialides in crowded verticils. Section Hypocreanum accommodates Trichoderma anamorphs of Hypocrea that have effuse conidiation, sparingly branched conidiophores, and cylindrical to subulate phialides. The placement of existing Trichoderma species, species aggregates, and some anamorphs of Hypocrea in the five sections is discussed, and a key is provided to differentiate the sections of Trichoderma. Key words: Trichoderma, sectional classification, Hypocrea, Gliocladium.