Gelidium amansii

Thallus bushy, cartilaginous, solitary or gregarious, caespitose, erect, (5)-10-20(-30) cm high, dark purple-red. Branching pinnate (to four-five orders), alternate or opposite. Broad main axes and branches flattened to flat, to 2 mm wide, often tapering in upper portion. Narrow branches terete. Determinate branchlets subulate, simple or branched. Tetrasporangial sori develop on elongate-ovate or oblong-spatulate branchlets, Tetrasporangia rounded to ovate, cruciate, 20-33×26-40(-55) mm. Cystocarps borne on small determinate branchlets, 0.5-0.6(-1.0) mm diam. Attachment by rhizomatous holdfast, bearing many erect axes. Growing on rocky at low intertidal to subtidal (10 m deep).

Temperate and subtropical latitudes of Pacific and Indian Oceans.