Which generic name you prefer: Trichoderma or Hypocrea?

In brief: The ISTH as a subcommission of the International Commission on the Taxonomy of Fungi (ICTF), is expected to decide on the names in Hypocrea and Trichoderma.

Dear ISTH members,

among several changes a drastic change of the ICBN (International Code of Botanical Nomenclature) was adopted at the IBC in Melbourne in July 2011 for fungi: from 1 January 2013 only one official name will be allowed for each pleomorphic fungus.

The question of which name to use generally follows the principle of priority of publication, BUT

• a new passage in Art. 57.2 says that an anamorph-typified name (e.g. Trichoderma) that has priority must not be taken up until retention of the teleomorph-typified name (e.g. Hypocrea) has been considered by the General Committee and rejected.
• mass conservation: A new Art. 14.n says that lists of preferred names may be submitted to the General Committee, which will refer them to the Nomenclature Committee for Fungi and committees of experts for examination. After approval, these names will then become permanent, i.e. treated as conserved.

Currently some subcommittees for several groups of fungi are being formed, which are expected to provide draft lists of fungal names for examination and final conservation.

The ISTH as a subcommission of the International Commission on the Taxonomy of Fungi (ICTF), is expected to decide on the names in Hypocrea and Trichoderma.

Note that priority of names will have to be decided at both specific and generic levels.

As a first step it has to be decided, which generic name has to be used in future, Hypocrea OR Trichoderma.

To facilitate your decision, we provide the respective changes as an attachment and the following arguments for and against each generic name:

Hypocrea is the teleomorphic name. Iit is younger (1825) than Trichoderma, i.e. theoretically it has no priority of publication, but see above concerning Art. 57.

Arguments for the exclusive use of Hypocrea:

• continuation of the well-practiced principle of naming the whole fungus with the teleomorph name;
• an exclusive use of Hypocrea would necessitate fewer new combinations (ca. 90) than an exclusive use of Trichoderma (ca. 230);
• over recent years Hypocrea has gained much acceptance, even for species that are important in industry, such as Hypocrea jecorina versus its anamorph Trichoderma reesei;
• the diversity of species forming Hypocrea teleomorphs exceeds that of Trichoderma (species that had mainly been addressed as soil fungi). In fact, for isolates from soil much fewer species have been described.

Trichoderma is the anamorphic name. It is older (1794) than Hypocrea, i.e. basically it has priority of publication, but see above concerning Art. 57.

Further arguments for the exclusive use of Trichoderma:

• a much higher number of citations in applied microbiology and biotechnology due to the wide use in economic applications and considerations;
• frequent sampling from soil and other natural substrata;
• exclusive result of isolation and most culture work;
• higher degree in morphological variation in some groups of the genus.

Note the arguments against the exclusive use of Trichoderma:

• It would disrupt the well-understood and well-applied use of teleomorph names for the holomorph.
• An exclusive use of Trichoderma would necessitate more numerous new combinations (ca. 230) than an exclusive use of Hypocrea (ca. 90).
• In addition to Hypocrea species that have been described recently and particularly those that do not form an anamorph, this would affect all older Hypocrea names/species that have not yet been re-studied by molecular methods.
• Material from nature deposited in herbaria is nearly exclusively present as Hypocrea teleomorphs. Type material of Trichoderma spp. usually consists of dried agar cultures, whilst a re-examination always has to go back to the living state. If Trichoderma is adopted, old teleomorph names will soon be forgotten; it is also likely that many homonymous epithets will be introduced, as has been even done recently, e.g. Trichoderma amazonicum was established although there is already a Hypocrea amazonica, which has probably nothing to do with the new taxon. For that Hypocrea then a new epithet would have to be introduced in Trichoderma. This is just one of many problems that have to be resolved at the species level later on.

We hope that this is sufficient information to aid you in your decision. Please give us your opinion!

The outcome of this poll, which will be regarded as a democratic decision, will be reported to the ICTF and the NCF.

Walter Jaklitsch & Irina Druzhinina, assisted by Walter Gams

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