Apoglossum minimum and A. gregarium (Delesseriaceae, Rhodophyta),Two New Records from Korea

Abstract

Collections from subtidal habitats often include various tiny delesseriacean algae. Assigning them to appropriate positions has frequently been difficult, especially between Delesseria and Apoglossum. Apoglossum was erected as a subgenus of Delesseria Lamouroux by J. Agardh (1876) and later was elevated to the generic level by the same author (Agardh 1898). Agardh (1898) distinguished Apoglossum from Hypoglossum Kutzing, considered as a related genus, primarily by the presence of conspicuous microscopic lateral veins and the irregular arrangement of cells. Confusions in generic criteria, however, occurred in relation to Delesseria rather than to Hypoglossum because the above characteristics can be found in both. Kylin (1923) clarified the both genera after a close examination of their type species. Currently accepted features to identify Apoglossum are mainly based on Kylin (1923) and Wynne (1984): 1) intercalary cell divisions are absent in the primary cell row but occur in the higher order cell rows, 2) not all the third order cell rows reach the blade margin, 3) branches arise from the midrib, 4) lateral pericentral cells remain undivided, 5) when the midrib is cross sectioned, rhizoidal cells are confined to either side of the central large cells, 6) the fourth order cell rows are on the adaxial but not on the abaxial side of the third order rows, and 7) each sterile cell group remains single. When establishing Apoglossum, J. Agardh (1898) included six species, A. decipiens (J. Agardh) J. Agardh, A. montagneanum (J. Agardh) J. Agardh, A. oppositifolium (Harvey) J. Agardh, A. tasmanicum (Mueller) J. Agardh, A. violaceum (J. Agardh) J. Agardh, and the type species A. ruscifolium (Turner) J. Agardh. Two of them, A. violaceum and A. decipiens, were transferred to Delesseria by Kylin (1924). Five more species, A. minimum Yamada, A. punctatum Dawson, A. spathulatum (Sonder) Womersley et Shepley, A. gregarium (Dawson) Wynne and A. unguiculescens Millar, were newly added from Japan, Mexico and Australia (Yamada 1944; Dawson 1966; Womersley and Shepley 1982; Wynne 1985; Millar 1990; Millar and Wynne 1992); among them, A. punctatum was reduced to a synonym of Grinnellia lanceolata Dawson (Wynne 1985). The genus Apoglossum, therefore currently including eight species, has been known to occur in British waters, the Mediterranean, South Africa, the eastern Pacific Ocean, Australia, New Zealand, and Japan (Greville 1830; Harvey 1849; Yamada 1944; Womersley and Shepley 1982; Wynne 1984, 1985; Ballantine and Wynne 1985; Millar and Wynne 1992; Maggs and Hommersand 1993; Silva et al. 1996). We collected Apoglossum species from the subtidal zone as a first record in Korea and identified as previously known species, A. minimum from Japan and A. gregarium from the Gulf of California. We described their morAlgae Volume 21(4): 425-432, 2006