Orsis, 8: 151 (1993) Validation of Goniomitrium seroi Casas Creu Casas Botinica. Facultat de Citncies. Universitat Autbnoma de Barcelona. 08193 Bellaterra Goniomitrium seroi was described in Casas 1972. The name, however, is not valid because a single element was not cited as a holotype (Crosby et al. 1992, article 37.3 of the International Code of Botanical Nomenclature, Greuter 1988). I correct the oversight here: Goniomitrium seroi Casas in Casas, Acta Phytotaxonomica Barcinonensia 10:13. 1972. Holotype: Spain, Almeria, Sierra del Cabo de Gata, prope Cortijo del Monsul, UTM. 31SWF76, rupibus volcanis, C. Casas, 23 Mars 1972, BCB 2397. References Casas, C. 1972. Goniomitrium seroi sp. nov. en la Sierra del Cabo de Gata. Acta Phytotax. Barcinon. 10: 1015. Crosby, R., Magill, R.E. & Bauer, Ch.R. 1992. Index of Mosses 1963-1989. Monographs in Systematic Botany from the Missouri Botanical Garden 42: 1-646. Greuter, W., ed. 1988. International Code of Botanical Nomenclature. Regnum Vegetabile 118: 1-328. Manuscript received on November 1992