The following notes refer to the typification of the two oldest species names applied in the genus Gelidium, including also comments on other related topics. Gelidium is probably the most confused genus, both nomenclaturally and taxonomically, of the Rhodophyta. This investigation began in an attempt to determine the correct names to be applied to the British species of the genus, but it was soon discovered that a much wider geographical consideration was necessary. I would like to take this opportunity to pay tribute to the help and assistance which has been afforded by Dr. J. Th. Koster in this and other investigations, over a period of many years. Extreme ecological and seasonal polymorphism are the principal causes of the present situation in the genus Gelidium. Extensive fieldwork over the past seventeen years has given some indication of the limits of taxa (Dixon, 1958, 1966), in so far as the European representatives are concerned. The nomenclatural problems are, however, still largely untouched. The purpose of the present paper is to examine critically the typification of the two oldest epithets referred to the genus Gelidium. These are: 1. cartilagineum, based on Fucus cartilagineus Linnaeus (1753), 2. corneum, based on Fucus corneus Hudson (1762).