Amphiroa fragillissima and Amphiroa rigida
Calcified, fragile, white, pink or purple; repeatedly
branched. Branches fine, circular in cross section, jointed. A. fragilissima
more delicate, dichotomously branched segments shorter than 1 mm and slightly
swollen at each end. Joints of A. rigida longer than 1 mm
and not swollen at ends. Isolated clumps in exposed places; great carpets
in shallow sand coves; also common on patch reefs.