Halimeda discoidea

Thallus compact, or forming loose cushion-like clumps, erect, 5-15(-20) cm high, bright green, grayish-green or whitish. Branching sparingly di-trichotomous, in one plane. Segments soft, slightly calcified, flat, discoid, reniform, sometimes broadly cuneiform, 1-3.2(-4) cm wide, 1-2.0 cm long, 0.3-1.2 mm thick, slightly decreasing from the base to upper portions. The outer margins of the segments entire, undulating, sometimes cleft. The basal 1-2 segments subterete, or stipe-like. Utricles in surface view polygonal, 42-50×30-40 mm. In longitudinal section utricles consisting of 2-3 layers, the surface utricles 45-50 mm in diam., 50-80 mm long. Subsurface utricles large, 90-110 mm diam., 125-150 mm long, supporting 4-8(-10) surface utricles. Attachment by small holdfast, consisting of rhizoidal mass tightly attaching to dead corals covered with sand in low intertidal, upper subtidal to a depth of 50 m.

Tropical and subtropical waters of Atlantic, Indian and Pacific Oceans.