The Indian Ocean, for the purposes of this catalogue, is defined as follows (see map). It is bounded on the west by the eastern shore of Africa as far south and west as Cape Agulhas. It is bounded on the east by the western shore of the Malay Peninsula and the southern coasts of Sumatra, Java, and the Lesser Sundas. The Strait of Malacca and Singapore are included. From the easternmost point of Timor, the boundary extends to Cape Londonderry, the northernmost point of Western Australia, and westward and southward to West Cape Howe, the southernmost point of Western Australia. Although the Indian Ocean, as sometimes defined, continues around the southern coast of Australia, we have excluded this region because its rich algal flora has been the subject of numerous scholarly monographs in which previous records are assessed and assigned to appropriate species, thus obviating the need for a catalogue in that region. In the southern part of the Indian Ocean we have included Amsterdam and St. Paul islands, but have excluded Iles Kerguelen and other subantarctic islands. Because the algae of the Red Sea have been the subject of a previous catalogue (Papenfuss, 1968c), we have excluded that area.
We have compiled from the literature all Indian Ocean records of benthic marine algae that have been identified to species, including records in papers that are principally concerned with biochemistry, physiology, ecology, or mariculture. Previous compilations (such as De Toni's Sylloge algarum) are included. Although in general we have restricted the content of this catalogue to published opinions and records, when faced with problems involving South African algae we have consulted and cited the unpublished observations that G.F. Papenfuss assembled during 45 years of study. He tried to verify all published records of South African algae by examining the pertinent specimens housed in various European herbaria. He left notebooks, manuscripts, and annotations that convey his taxonomic opinion concerning these specimens. In the body of the catalogue we refer to this material as ``Papenfuss (notes)''.
Sequence of Taxa
Above the level of family, the sequence of taxa follows an assumed phylogenetic scheme, with class being the highest rank employed. While divisions (phyla) are important in general biological classifications and thus are of immediate concern to phylogeneticists, teachers, and textbook writers, we consider them irrelevant to the field phycologist for whom the catalogue was designed. Were we to include them, we would need to decide which names to use. The International Code of Botanical Nomenclature (ICBN) permits names of taxa above the rank of family to be taken either from distinctive characters, resulting in descriptive names, or from the name of an included genus, resulting in typified names (Arts. 16 and 17). The ICBN recommends (Rec. 16A.1) that the name of a division (phylum) end in -phyta for all plants except fungi, for which the ending -mycota is recommended. For algae, the ending -phycophyta is sometimes used (Papenfuss, 1946), but we prefer -phycota, which retains the link with algae but is shorter and parallels the fungal ending -mycota. Thus, if we were to include divisions in this catalogue, we would use the descriptive names Cyanophycota (with the single class Cyanophyceae), Rhodophycota (with the single class Rhodophyceae), Chromophycota (including Phaeophyceae and Xanthophyceae), and Chlorophycota (with the single class Chlorophyceae). We have used descriptive names for the five classes recognized in this catalogue, with the ending -phyceae as recommended by Rec. 16A.3.
We have considered the advantages and disadvantages of arranging the orders within a class alphabetically rather than phylogenetically. When forced by frustration to consult the index, we are inclined toward an alphabetical sequence, but keeping in mind the deeply engrained habit of looking for the Ceramiales at the end of the reds and the Ectocarpales at the beginning of the browns, we decided on a perceived phylogenetic sequence. At the level of family and below, all taxa are listed alphabetically: families within orders, genera within families, and species within genera. The sequence of infraspecific taxa, which is of greatest concern in Sargassum and Caulerpa, is less straightforward. When there is only one infraspecific rank within a species, the trinomials are arranged alphabetically. When both varieties and formae are involved, the varieties are listed alphabetically (except that the nomenclaturally typical variety is listed before other varieties), with formae listed alphabetically within a variety.
For each specific or infraspecific entry, the accepted name or its basionym is listed first, followed in chronological order by combinations or replacements of the basionym (i.e., homotypic or nomenclatural synonyms). Next, taxonomic (heterotypic) synonyms are listed in chronological order, again with the basionym listed first, followed in chronological order by combinations or replacements of the basionym. Lastly, misapplied names are listed according to the chronology of their misapplication.
For each name (except misapplied names) the author and place of publication are given. If a name was not formed according to the rules of the ICBN when it was published, we have made the appropriate corrections and appended the original spelling in single quotation marks within parentheses. The type locality of each accepted name and taxonomic synonym is indicated. When the orthography of the type locality as cited in the protologue differs from modern orthography, or when historical names differ from modern names, the modern equivalent is given in brackets. Centered headings of names with Indian Ocean types and basionyms of taxonomic synonyms with Indian Ocean types are preceded by an asterisk. All combinations of a basionym with an Indian Ocean type are listed on the assumption that the combining author was making a taxonomic statement about the type. For a basionym with a non--Indian Ocean type, a combination is listed only if it is the accepted name or if Indian Ocean records have been published under that name. For a basionym or combination with a non--Indian Ocean type, the phrase ``including Indian Ocean record'' has been added when the author simultaneously cited at least one Indian Ocean collection. Following each name is a chronological list of references to Indian Ocean records under that name. Usually the heading ``Misapplied name'' includes a reference to the authority for the misapplication, but in some instances this information is given in the accompanying note. The authority for taxonomic synonymy is always given in the accompanying note.
The reported distribution of species is indicated by an alphabetical listing of countries (e.g., Mozambique, Sri Lanka, Tanzania) or, where it seemed more informative, by geographic unit irrespective of political affiliation (e.g., Andaman Islands, Christmas Island). For Indonesian records deriving from only a few islands, the islands have been named, but when numerous islands are involved, Indonesia alone is listed. It should be kept in mind that Australia, Indonesia, South Africa, and Thailand all have extensive non--Indian Ocean as well as Indian Ocean coasts.
A note has been appended to many entries. These notes are primarily used to give the authority for taxonomic synonymy and less often the authority for misapplications. They also provide reasons for treating a name as invalidly published or illegitimate, explanations of unusual, complicated, or controversial taxonomic and nomenclatural situations, and discussions of alternative taxonomic opinions. Particularly long discourses have been removed to an appendix called Taxonomic and Nomenclatural Notes.
Throughout the notes there is frequent reference to the International Code of Botanical Nomenclature (Greuter et al. (eds.), 1994). Articles, recommendations, examples, and notes are cited from the current edition (the Tokyo Code) unless otherwise stated. Because the Tokyo Code incorporates substantial changes and a renumbering of articles and other components, the user of this catalogue is urged to obtain access to this current edition. The location of particular specimens (mostly types) is indicated by citation of herbarium abbreviations assigned by the International Association for Plant Taxonomy (P. Holmgren, N. Holmgren, & Barnett, 1990). References to pages of this catalogue are placed within square brackets while those in other publications are placed within parentheses. Usually, however, the distinction is made clear by the context.
An orphaned infraspecific taxon is a taxon that does not fit neatly into our chosen taxonomic and nomenclatural scheme. To make it fit would require an investigation leading to its disposal as a synonym or to its acceptance under a new combination, an investigation beyond the scope and means of this catalogue. Each such taxon is appended to the accepted taxon deemed most closely related. An example is the treatment of Caulerpa clavifera forma remota Svedelius, which follows the last entry of C. racemosa var. racemosa. Caulerpa clavifera (Turner) C. Agardh was placed in the synonymy of C. racemosa var. racemosa by Papenfuss & Egerod (1977), but not all infraspecific taxa within C. clavifera have been transferred to C. racemosa. It may be assumed that an investigation of the type of C. clavifera forma remota would result in an opinion regarding the taxonomic value and placement of this taxon. Approximately 70 orphans are included in this catalogue.
Various records have been excluded from the systematic part of this catalogue because they are under names of uncertain application or under names of taxa excluded from the Indian Ocean as defined herein. These excluded records are presented in an appendix in which the entries are listed alphabetically in one series, regardless of class.