Griffithsia japonica

Thallus soft, gelatinous, small, 1-4(-6.5) cm high, consisting of monosiphonous filaments, forming intertwined tufts or turf-like cushions, bright rose-red to purple. Branching dichotomous or subdichotomous in one plane, in the upper portion subdichotomously and partially unilaterally branched. Cells below cylindrical, clavate, ovoid to pear-shaped above, (125)-200-350(-1200) μm in diam., 3-6 diameters long. Sporangia develop on the top of cells and protected by a ring of large, incurved, sausage-shaped involucral cells. Sporangia spherical (80 μm in diam.) to obovoid, 58-60×75-80 μm, tetrahedrally divided. Cystocarps were not found. Holdfast inconspicuous; lateral fine rhizoids issuing from cells are common. Growing mostly epiphytic on larger algae in low intertidal and upper subtidal.

Note: Potential as a source of lectinshemagglutinins.

Tropical and subtropical seas of Indian and Pacific Oceans.