Notes on Ceramium (Rhodophyta: Ceramiales) from the Hawaiian Islands!

Ceramium is widely distributed and recorded from the coasts of the North Pacific Ocean. Thus, it is not surprising to find new species and new records of this genus among the numerous islands spread in this oceanic region. Extensive examination of material collected around O'ahu and other Hawaiian Islands has yielded two new records: Ceramium aduncum Nakamura (previously known from Japan), Ceramium clarionensis Setchell & Gardner (previously recorded for the Pacific coast of Mexico), and a new species, Ceramium cingulum Meneses. MATERIALS AND METHODS the island of O'ahu, Hawai'i, appearing in almost any collection made, mainly as epiphytes. Recently, four new species were recorded (Norris and Abbott 1992). The goal of the study reported here was to include all possible morphological variations in the Ceramium taxa collected. Thus, intensive collections were made around O'ahu, and collections from other Hawaiian Islands were examined. As a result three new records and one new species of Ceramium are reported. Haphazardly sampled collections were made at several sites around the island of O'ahu. Localities were chosen on the basis of habitat diversity and accessibility. Specimens were preserved in 2-5% buffered formalin/seawater and dried and pressed on herbarium sheets or fixed and preserved as whole mounts on permanent microscope slides. Material preserved on slides was stained with 1% aqueous solution of aniline blue slightly acidified with hydrocWoric acid (Tsuda and Abbott 1985). Plants were mounted in 25% solution of clear Karo com syrup (Best Foods, CPC International, Englewood Cliffs, New Jersey) in distilled water with a few crystals of phenol added as a preset:Vative<T-his~proGedurestained-a~:ial ceHsdifferentially from cortical cells in Ceramium, while highlighting the primary pit conections. Observations and measurements were made using a light microscope (Zeiss). 165 IManuscnpt aCceptedl May 1994. 2 Department of Botany, University of Hawai'i at Manoa, Honolulu, Hawai'i 96822. Current address: Departamento de Ecologia, Pontificia Universidad Cat61ica de Chile, Casilla 114-D, Santiago, Chile. APPROXIMATELY 55 SPECIES of the genus Ceramium (Ceramiaceae) have been reported for the tropical and subtropical North Pacific Ocean, representing about one-half of the known species worldwide. Detailed descriptions as well as passing references in marine floras of this region describe species mainly from the Pacific coast of North and Central America (Setchell and Gardner 1924, 1930, 1937, Dawson 1944, 1945a,b, 1954a,b,c, 1957b, 1961, 1962, Hollenberg 1948) and Japan (Yendo 1917, Nakamura 1950, 1965, Hono 1972, 1977). In Hawai'i, records of Ceramium species have been made since about 1876 (Abbott 1980), and a number have been published (Abbott 1947, 1980, Hollenberg 1968, Doty et al. 1974, Norris and Abbott 1992). Recognition and interpretation of seasonal and environmental modifications of the thallus (Dixon 1960, Garbary et al. 1978, Womersley 1978, Suh and Lee 1984) have contributed to a clarification of the taxonomic standing of some species in Ceramium. Thus, some of the originally described species have been reduced to synonymy, and the species delimitation in the genus is undergoing a series of changes resulting from critical examination of the diagnostic features. Species of Ceramium are common around