HARALDIOPHYLLUM-INFOSSUM SP-NOV (DELESSERIACEAE, RHODOPHYTA), A DIMINUTIVE TURF-FORMING RED ALGA FROM THE SOUTH-WESTERN PACIFIC

Haraldiophyllum infossum sp. nov. is a small red alga that is partiall y buried by sponges and ascidians in the turf community often under st ands of Ecklonia radiata (C. Agardh) J. Agardh. Blades are monostromat ic with conspicuously dentate margins and arise from creeping stolons. Spermatangial and tetrasporangial sori form elongate, interrupted pat ches along the mid-region of the blades. Features allying the new spec ies with the genus Haraldiophyllum include growth by means of many mar ginal initials, blades that are monostromatic except at their base and where reproductive structures are borne, absence of microscopic veins , procarps that are scattered over the surface of the fertile frond an d which are associated with two groups of sterile cells and one group of cover cells, and carposporangia that are borne singly and terminall y on gonimoblast filaments. Also important is the presence of a carpos porophyte fusion cell that incorporates gametophytic cells of the floo r of the cystocarp cavity. The supposed difference in orientation of t he two periaxial cells relative to the longitudinal axis of the frond (mostly parallel in Haraldiophyllum and mostly perpendicular in Nitoph yllum) is argued to be of little taxonomic significance. The only two characters which indisputably separate the genera are shown to be the number of sterile cell groups in the procarps and the fusion-cell anat omy. Similarities between the procarps of Haraldiophyllum and Hideophy llum, in which cover cells are present, are discussed in relation to t hose of the closely related genera Calonitophyllum, Nitophyllum, Myrio gramme and Valeriemaya.