AGLAOTHAMNION-OKIENSE SP-NOV (CERAMIACEAE, RHODOPHYTA) FROM THE SEA OF JAPAN

A new minute species of Aglaothamnion is reported from the Sea of Japa n. Thalli are 2-5 mm in height, tufted with one to several main axes w hich become distally indistinct, robust, light pink, commonly ecortica te. Vegetative cells are uninucleate. The first order lateral branches are radially alternate in arrangement. Basal rhizoids produced second ary upright axes. Plants are dioecious. The carpogonial branch cells a re arranged in zigzag or straight fashion. Gonimolobes are irregularly lobed and narrow to pointed. Spermatangial mother cell filaments are parallel to the adaxial surface of the male fertile segment, and each mother cell produces 1 -4 uninucleate spermatangia. Tetrasporangia are sessile, 1-3 per fertile segment, obovate to subspherical, 36-53 x 50 -59 mum in size and divide tetrahedrally but occasionally cruciately.