 And the "natural swing" around the forest of Looking-glass mangrove in fact is formed by the growing White-flower Derris.There are four main kinds of seaweeds in Hong Kong.They are "Halophila beccarii" (), "Halophila ovalis" (), "Ruppia maritimia" () and Dwarf eelgrass "Zostera japonica" () among which "Zostera japonica" was first found in Lai Chi Wo in 1979.