INTRODUCTION The Herbarium of the University of Porto (PO), located in the Institute of Botany “Dr. Gonçalo Sampaio”, is one of the most important on the Iberian Peninsula with about 122,000 specimens belonging to all plant groups. The lichen herbarium includes about 6000 specimens and comprises a general herbarium with spec- imens from Europe, a Portuguese herbarium with local specimens, and several special collections, the most important being Gonçalo Sampaio’s collection with c. 4000 specimens, mostly from Portugal. Gonçalo António da Silva Ferreira Sampaio (1865–1937), Professor of Botany in the University of Porto, was a renowned investigator mainly through his studies on vascular plants, but he also studied non-vas- cular groups, mainly lichens (Pires de Lima, 1938). In fact, for over two decades Sampaio collected lichens all over Portugal, mainly in the provinces of Minho, Trás- os-Montes e Alto Douro and Douro Litoral. According to our interpretation, Sampaio authored the name of one lichen genus, 87 names of lichen species (60 described as new species), and 14 names of infraspe- cific taxa. However, it is sometimes difficult to distin- guish between new names and new nomenclatural com- binations in Sampaio’s papers. This is due to his usual custom of citing only one author for a name even in nomenclatural combinations, viz., the author of the com- bination. In some cases (especially in Sampaio & Crespí, 1927) the epithet used and the taxonomic relationships expressed allow one to presume that Sampaio intended to make new combinations, so that it is difficult to interpret whether the names should be considered nomina nuda or combinations without basionym author citation. In the simple case in which the presumed new combination appears alone, these have been treated as technically nomina nuda, not being validly published under the pro- visions of Art. 33.2 of the ICBN (Greuter & al., 2000), even where Sampaio’s intent to publish a new combina- tion seems clear. In a number of cases, however, the sit- uation is complicated by the fact that the presumed new combination has a synonym associated with it. If not treated as a new combination, the name would be valid- ly published as an illegitimate replacement name for the cited synonym, which was clearly not in the least Sampaio’s intention. Art. 33.6, dealing with incorrect citation of a basionym, treats as validly published com- binations that would otherwise be validly published either as nomina nova or as names of new taxa, whereas Art. 33.2 specifies that, where no basionym is cited at all, a presumed new combination is validly published if it would otherwise be validly published as the name of a 771 Paz-Bermúdez & al.  Typification of lichen names 51  November 2002: 771–785 Typification of names of lichen taxa described by G. Sampaio and some others, deposited in Porto Herbarium (PO)* Graciela Paz-Bermúdez 1 , Helena Aguiar-Branco & Elisa Folhadela Herbário do Instituto de Botânica “Dr. Gonçalo Sampaio”, Universidade de Porto, Rua do Campo Alegre 1191, 4150-181 Porto, Portugal 1 Permanent address: Departamento de Botánica, Facultade de Bioloxía, Universidade de Santiago, 15706 Santiago de Compostela, Spain. E-mail: bvgraci@usc.es Gonçalo Sampaio authored 103 new names of lichens, comprising one new genus, 60 new species, 14 new infraspecific taxa, 25 new combinations and two nomina nova. In addition, he proposed 42 “names” that were not validly published, 18 of these being simple nomina nuda and 21 apparently representing invalid attempts to publish new combinations. The type material is deposited in the Herbarium of University of Porto (PO), except in three cases. Apart from a few specimens from Spain, the material derives from Portugal. For the names of all new taxa the type collections are listed, either a holotype or a lectotype (usually here designated). In addition, a few lichen names authored by Maurice Bouly de Lesdain or William Nylander and based on Portuguese material preserved at PO are listed with indications of type. KEYWORDS: herbarium, lichens, Portugal, Sampaio, Spain, typification. *In memoriam Aurea C. Carvalho (†), our colleague and friend who started this research with us.