This fourth revision of M. J. Wynne's Checklist is an exhaustively prepared and updated compilation of the taxa of benthic marine algae, or seaweeds, currently recognized in the broad area of the tropical and subtropical Western Atlantic. Thus, this checklist covers the region from the warm temperate eastern United States (Cape Hatteras of North Carolina) to southern Brazil, which corresponds to the same domain as the 1960 algal flora published by W. R. Taylor. This fourth revision of the checklist includes a total of 1,553 species of benthic marine algae: 215 members of the Ochorophyta (Pelagophyceae Phaeophyceae, and Xanthophyceae), 1,014 Rhodophyceae, and 324 Chlorophyeae. When 175 infraspecific taxa are included, the total tally of current names is 1,728. Taxonomic synonyms are also included andare listed in brackets after the current names. There have been many molecular-based phylogenetic studies in recent years, and their impact on classification has been incorporated into the present system in the various groups. There are 774 notes in regard to specific points related to nomenclatural issues, new records, new taxa, and other pertinent information. This publication includes an extensive bibliography of pertinent literature primarily for the period following the publication of the third revision of the checklist in 2011. This checklist includes a table listing new references by geographic region (country or coastal states of the Southeastern USA). This work will be a useful and timely resource to workers on marine algae not only of the western Atlantic but also on a global perspective because of its synthesis of recent literature and its presentation of the most modern concepts of algal classification. schovat popis