Avrainvillea erecta

Thallus blade-like, erect, solitary, sometimes in clusters. Blades flat, flabellate, subcuneate or reniform, thick to 1 mm, 1-6 cm high, 2.5-10 cm broad, soft, shortly stipitate to subsessile, dark green with brownish margins in adult plants. The blade consists of loosely woven filaments. Cortical filaments cylindrical, slightly moniliform, 27-45 mm diam., di-, tri-polychotomous, strongly constricted at the dichotomies, branching in various planes and forming feltlike texture. Medullar siphons cylindrical 35-60(-70) mm diam. Margins entire, fimbriate or lobed. Holdfast stout cylindrical or subcylindrical consists of densely interwoven rhizoids together with coral sand particles, shell fragments and fine sediments, 2-9(-16) cm, 1-1.8(-2.5) cm diam., deeply sunken in silt or coral sand. Growing in protected areas on sandy or muddy bottom, intertidal, subtidal (to 15 m deep).

Indian and Pacific Oceans (subtropical and tropical waters).