Gelidium amansii (Lamouroux) Lamouroux
Gelidium amansii is a species of marine Rhodophyta (red algae), with a purple red or yellowish red body, cartilaginous, erect in tufts at a height of 8-30 cm, differentiated into upright and creeping stems. The upright stem is flat linear-shaped with 4-5 pinnate in opposite or alternate at a diameter width of 0.1-0.2 cm, thinner on the edge. The creeping stem is thread-like rhizoid. Depending on the various habitats, the body is diversely formed. It is uniaxial with one apical cell and whorled cells generating from the axial cell towards both sides. The internal pith is dense elongated cell filaments, and the epidermis is formed by tiny round cells; and between, there are many tabular root-like cell filaments parallel to the axis. The cell wall is rich with algin.
Gelidium amansii is perennial, mainly distributed in Korea, Japan, Ryuku Islands, mainland China (Shandong Peninsula, Zhejian and Xiamen), the Philippines, Malaysia, Indonesia, Singapore, Sri Lanka, Mauritius, etc. In Taiwan, it grows in the northern and northeast coasts, which can be seen all year round in the habitat from the low tide line to the subtidal reefs within 3-10 meters deep. Usually, they live in the off-shore area with speedier water and higher transparency. Due to the rich algin in their cell walls, they are significant economically-valued seaweed to extract agar.