Caulerpa sertularioides

Thallus grass green, consisting of creeping, coarse stolons bearing erect feather-like branches above and rhizoids below. Branches 2.5-5(-20) cm high, 4-5(-20) mm wide, stalked (1-3 mm high). Central axis cylindrical, 430-500(-1000) mm diam. Branchlets (pinnules) distichous, opposite, linear-cylindrical or needle-like, (120)-180-400 mm diam., 1.8-5(-11) mm long, mostly upcurved, not constricted at base. Apices rounded conical and mucronate. Stolons branched, stout, naked, (0.5)-2.0-2.5 mm diam., to 0.3 m long. Rhizoids dichotomously branched, gradually tapering to apices. Growing on hard substrates covered with sand, sandy bottom with rocks, in middle, lower intertidal, subtidal (to 10 m deep), in sheltered and moderately wave-exposed sites, often in association with seagrasses.

Subtropical and tropical waters of Atlantic, Indian and Pacific Oceans.