(1606) Proposal to conserve the name Peperomia nitida Dahlst. against P. nitida Sessé & Moc. (Piperaceae)

Abstract

The name Peperomia nitida Dahlst. was published with an extended protologue and has a well conserved type (the specimen number, 3985, in the protologue is an evident typographical error as the Mosen 3986 herbarium sheet is clearly as Peperomia nitida by Dahlstedt whereas Mosen 3985 is even a Peperomia). It refers to a clearly distinguished species occurring in southeastern Brazil, which is well-represented in herbaria, and variants of which are widely spread in the horticultural circuit. In the latest general review of the genus Peperomia (C. de Candolle, Piperaceae clavis analytica, Candollea 1: 65-415, 1923, published posthumously), P nitida Dahlst. is included in the index as an accepted species, although it is included in the key. The reason for this, which is the case for about another 5% of the taxa in this publication, including some of C. de Candolle's own species, is the unexpected death of the author while the was completely finished. The species is fully treated in Yuncker's Piperaceae of Brazil III (Hoehnea 4: 71-413, 1974, cf. pp. 208, 221 & 398) being keyed, described, illustrated and reference provided to the type and other known herbarium collections. Peperomia nitida Sesse, & Moc. refers to a Mexican plant that was discovered by Sesse and Mo9ifio during the Royal Botanical Expedition to New Spain (1786-1804). However, the taxon was published until 85 years after the death of Martin de Sesse, leader of the expedition, and 73 after that of Jose Mo;ifio. The protologue was based on field notes found in the archives of the authors and by no means on a manuscript ready for publication. These field notes contained the name and a description but no reference to any type specimen. Until now no specimen of the Sesse & Mo9ifio herbarium collection or any of the coloured plates produced during the expedition has been linked to this name. With the lack of a type specimen or an illustration, only the description is available to determine the application of the name. This has never happened. McVaugh, who thoroughly studied the Sesse & Mo;info material, describes this taxon as not identified (Bot. Results Sesse & Moc. Exped. 7: 433, 2000) and, although it certainly has some historical interest, it has little or no botanical meaning. The name is mentioned in no publication since its original appearance except that of McVaugh (l.c.) and has never been used in any way. Its rejection would have no disadvantages. Application of the rule of priority makes P nitida Dahlst. an illegitimate later homonym, despite its effective use today, and, without conservation, it would be necessary to replace it with a nomen novum. This would certainly be a disadvantageous nomenclatural change as described in Art. 14 of the ICBN (Greuter & al., Regnum Veg. 138. 2000). The fact that, since its original publication, P nitida Dahlst. is known to figure in only two regular printed publications might suggest that the case for its conservation is a very strong one. I should emphasise, however, that the majority of the 1545 currently accepted Peperomia species (G. Mathieu, Taxonomic Repertory of the Genus Peperomia, update Aug 2003, www.peperomia.net/repertory.asp) are mentioned in only a few publications. In the two centuries since Ruiz & Pavon established the genus (Fl. Peruv. & Chil. Prodr., 1794), only five botanists (Miquel, C. de Candolle, Trelease, Yuncker, and Callejas) have dedicated any significant part of their careers to the study of this genus. The genus has been such a challenge to researchers that most of them only dare treat it for a restricted area or prefer to treat it at all. It is surprising that many taxa have been cited only occasionally, and that the historical legacy is one of knowledge gaps and controversial taxonomic opinions. The current widespread use of P nitida Dahlst. may be illustrated by its presence in frequently consulted online databases. It figures in the w3 Tropicos taxonomic database (Missouri Botanical Garden, mobot.mobot. org/W3T/Search/vast.html.), and nine collections are mentioned in the online Catalogue of the Vascular Plant