Philippines is considered as the center of Kappaphycus biodiversity in the world. Currently, six Kappaphycus species are recognized to occur in the Philippine archipelago. Different strains of cultivated eucheumatoids exhibit different phenotypes, with coloration the most distinct. Phytochrome-regulated sensory system in photosynthetic organisms controls the production of proteins used to capture light for photosynthesis. The control of pigmentation by light is called complementary chromatic adaptation (CCA) which is photoreversible. However, culture studies showed that wild brown-green bicolor tetrasporophyte produced next generation of gametophytes with a host of colors from red, brown, and green, and shades in between. On the other hand, wild dark brown cystocarps within the female gametophyte produced next generation of tetrasporphytes that were dark green. Considering that the wild specimens were collected on the same reef flat and the culture and environmental conditions of the progenies in the laboratory and in the outdoor nursery are comparable, the expression of particular coloration must be adaptive and within the species’ natural pool of genetic variability.