International Code of Botanical Nomenclature

(Saint Louis Code), Electronic version


Article 58

58.1. The epithet in an illegitimate name if available may be used in a different combination, at the same or a different rank, if no other epithet is available from a name that has priority at that rank. The resulting name is then treated as new, either as a nomen novum with the same type as the illegitimate name (see also Art. 7.5 and Art. 33 Note 2), or as the name of a new taxon with a different type. Its priority does not date back to the publication of the illegitimate name.

Ex. 1. The name Talinum polyandrum Hook. (1855) is illegitimate, being a later homonym of T. polyandrum Ruiz & Pav. (1798). When Bentham, in 1863, transferred T. polyandrum Hook. to Calandrinia, he called it C. polyandra. This name has priority from 1863, and is cited as C. polyandra Benth., not C. polyandra (Hook.) Benth.

Ex. 2. While describing Collema tremelloides var. cyanescens, Acharius (Syn. Meth. Lich.: 326. 1814) cited C. tremelloides var. caesium Ach. (Lichenogr. Universalis: 656. 1810) in synonymy, thus rendering his new name illegitimate. The epithet cyanescens was taken up in the combination Parmelia cyanescens Schaer. (1842), but this is a later homonym of P. cyanescens (Pers.) Ach. (1803). In Collema, however, the specific epithet cyanescens was available for use, and the name C. cyanescens Rabenh. (1845), based on the same type, is legitimate. The correct author citation for Leptogium cyanescens, validated by Körber (1855) by reference to C. cyanescens "Schaer.", is therefore (Rabenh.) Körb., not (Ach.) Körb. nor (Schaer.) Körb.

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