DUDRESNAYA-KUROSHIOENSIS SP-NOV (DUMONTIACEAE, RHODOPHYTA) FROM JAPAN

The marine red alga Dudresnaya kuroshioensis sp. nov. (Dumontiaceae, R hodophyta) is described from southernmost Honshu, Japan. It is a deep- water species with the following characters: terete, radially branched and not villose thalli, hexagonal crystals in axial cells, hairs, dis tinct primary axes, cylindrical outer cortical cells, rhizoids up to 2 1 mum in diameter, carpogonia once obliquely or transversely divided, a distinctly cleft cystocarp and an isomorphic alternation of generati ons. It lacks annulations in young branches, indeterminate-axis primor dia, rhizoids with cortical laterals, a mucilage coat around the carpo gonial and auxiliary-cell filaments; gonimoblast initials may or may n ot be recurved around their auxiliary-cell filaments. Dudresnaya kuros hioensis is compared to Japanese, Austral-Pacific and North American s pecies that most resemble it anatomically but differ in at least one s ignificant character. It is concluded that the Australian D. capricorn ica is probably the closest relative of the new species, differing mai nly in overall size, rhizoid diameter and the anatomy of the mature cy stocarp.