A Taxonomic Review of Hawaiian Gelidiales ( Rhodophyta )

The present study reviews most collections of Gelidiales known from Hawaii. Three genera, each one including four species, are recognized among nearly 350 specimens examined. The genus Gelidiefla is represented in Hawaii by G. acerosa (Forsskal) Feldmann et Hamel, G. adnata Dawson, G. machrisiana Dawson, and G. myrioclada B0rgesen. The genus Gelidium includes G. crinale (Turner) Lamouroux, G. pluma Loomis, G. pusillum (Lamouroux) Le Jolis, and G. reediae Loomis. The genus Pterocladia is represented in Hawaii by P. bulbosa Loomis, P. caloglossoides (Howe) Dawson, P. caerulescens (Kutzing) Santelices, and P. capillacea (Gmelin) Bornet et Thuret. Only six of the 21 species of Gelidiales previously reported for Hawaii were found to be represented in the material studied. There is evidence of misidentification in at least eight cases, and two specific epithets based on Hawaiian specimens are considered to be synonymous with other species. Five species previously reported from Hawaii are still unchecked due to their absence from the material studied. Seven previously unreported species of Gelidiales were added as new records for the Hawaiian flora. A key is given that identifies the Hawaiian Gelidiales, and this is followed by a description, with illustrations and a discussion, of each ofthe 12 species found. TWENTY-ONE SPECIES of the red algal order Gelidiales have been so far reported for the Hawaiian Islands. The first eight were published by Chamberlain (1860), all of them lacking descriptions and exact indications of locality, and several with nonvalid specific epithets. Eight other species were listed later by Reed (1907), these also without descriptions and more than half of them with tentative determinations only. Two more were added by Neal (1930) from her ecological study at Waikiki. The species were identified as Gelidium sp. 1 and Gelidium sp. 2, with descriptions so general that they cannot be identified now. In 1960, Loomis described and illustrated five new species from Hawaii. Loomis stated that the Hawaiian specimens were collected by Reed and distinguished them with Reed's number. Regrettably, Reed gave no numbers in her publication and it is now unclear I Manuscript received 5 December 1975. 2 University of Hawaii, Department of Botany, Honolulu, Hawaii 96822. Present address: Departamento de Biologfa Ambiental y de Poblaciones, Instituto de Ciencias Biol6gicas, Universidad Cat6lica de Chile, Casilla 114-D, Santiago, Chile. ifany or all the new species described by Loomis correspond to any of the forms originally listed by Reed with tentative names. The present study was started in order that the taxonomy of the Hawaiian members of the group might be clarified. It was expected that such a review would reduce to less than 21 the number of species recognized for Hawaii, independent of the possibility that new records for the islands might be added later. Special emphasis was placed on studying the herbarium collections on which the previous identifications had been based, as well as on examining new collections present at various institutions. The herbarium of the Allan Hancock Foundation provided the type specimens of three species of Gelidium described from Hawaii; the herbarium of the University of California had the type specimens of three species of Pterocladia together with almost 120 mostly unidentified specimens of gelidioid algae collected in Hawaii by E. Y. Dawson, M. Reed, W. A. Setchell, and]. Tilden. The Bernice P. Bishop Museum lent close to 80 specimens collected by M. S. Doty, M. Reed, ]. F. Rock, W. A. Setchell,