繡球雀屏珊瑚

zooxanthellate

Colonies are a mass of small, vertical and irregular leaves, each being no more than a few cm tall. Leaves are always thin, not more than 4-5 mm thick, and the basal parts of a high proportion of leaves are dead and sometimes actually detached from the jumble of older fronds of the colony. Septa are less than 1 mm diameter and lie flush with the surface of the leaf. They run in rows parallel to the edge of the leaf. Rows are separated by 3 or 4 mm. The species is mostly found in sheltered and lagoonal areas where it is usually very common. It tolerates sediment well, and reaches its greatest abundance and colony size between 3 - 10 m deep in calm areas. There, "supercolonies" are frequently encountered. These are growths of the same species from one or more original colonies, which have detached and spread over wide areas. Thus Pavona cactus may provide about 75% cover, for example, over 10 square metres or more (Sheppard, 1998). Colonies are thin, contorted, bifacial, upright fronds with or without thickened branching bases. Corallites are fine and shallow, and aligned in irregular rows parallel to the margins. Colour: pale brown or greenish-brown. Abundance: Abundant in some lagoons and on upper reef slopes, especially those of fringing reefs, and in turbid water protected from wave action, where colonies frequently exceed 10 m in diameter (Veron (1986)). Tropical Indo-Pacific in Kalk (1958).