LAURENCIA KANGJAEWONII SP-NOV (CERAMIALES, RHODOPHYTA) FROM KOREA

Laurencia kangjaewonii sp. nov. (Ceramiales, Rhodophyta) is described from subtidal habitats of eastern and southern Korea. Plants are stron gly compressed throughout, with alternate distichous branching. Vegeta tive axial segments have two pericentral cells. Spermatangial branches are produced from adaxial lateral branches borne on suprabasal cells of trichoblasts that arise from axial cells in terminal cup-shaped spe rmatangial pits. Other features of the male reproductive structure are typical of the 'trichoblast' type. Procarp-bearing segments cut off f ive pericentral cells, the fifth of which becomes the supporting cell. Procarps have a four-celled carpogonial branch with two sterile group s, and the post-fertilization development is essentially the same as i n other species of Laurencia Tetrasporangia are produced from 3(4) add itional pericentral cells in fertile segments. Laurencia kangjaewonii shares several features with the subgenera Laurencia and Chondrophycus , including: parallel arrangement of tetrasporangia (subgen. Laurencia ) and absence of secondary pit-connections between adjacent epidermal cells (subgen. Chondraphycus). The vegetative axial structure and tetr asporangial features strongly suggest that the new species is more clo sely allied to the subgenus Chondrophycus than to the subgenus Laurenc ia. Anatomical characters of the new species are compared with those o f other related species.