Morphology of Laurencia cartilaginea Yamada (Rhodomelaceae, Rhodophyta)
摘要
Vegetative structure and reproductive organs of Laurencia cartilaginea Yamada were studied. Each axial segment, which is discernible only near the apex of branchlet, is provided with a trichoblast and two pericentral cells. Only in a tetrasporic plant, all of the axial cells show an addition of the pericentral cell number, as a result of the additional production of fertile pericentral cells; each of which produces a tetrasporangium. The first and second pericentral cells always remain sterile. Spermatangia are produced at trichoblast which is derived from an axial cell and the antherial trichoblast always consists of sterile and fertile branches. The second segment of the female trichoblast forms young procarps provided with five pericentral cells. The fifth of which always acts as the supporting cell. L. cartiaginea is easily distinguished from a similar species, L. undulata Yamada by the rostrated cystocarp and the conspicuous projection of epidermal cells at the distal end of ultimate branchlets.