Codium spongiosum Harv.

Scientific Description

Habit and structure. Thallus applanate or pulvinate, lobed, spongy, becoming gelatinous in formalin solution, 10 (–25) cm wide, to 2 cm thick, loosely adhering to the substratum. Medullary filaments mostly 30–100 μm diam., one arising from the base of each utricle by a stout outgrowth so that the utricle and filament intergrade. Utricles dissecting out into groups resulting from direct production of new utricles from parent utricles; young utricles cylindrical, 1.4–2.0 mm long, 130–390 μm diam.; mature utricles 1.5–4.0 (–6.0) mm long, to 520 μm diam. at the subtruncate to rounded apex, enlarging basally to 850 μm. Utricular wall 2–3 μm thick, very slightly to moderately thickened (–32 μm) at the apex; thickened apices finely lamellate and slightly introrsely umbonate. Hairs (or hair scars) abundant, forming a band c. 120–200 μm wide and 130–430 μm below the utricle apex. Gametangia lanceolate-ovoid or ampulliform, 215–360 μm long, 50–175 μm diam., usually several per utricle, each borne on a short pedicel in a zone 360–660 μm below the apex.

Distribution. Widespread in all tropical and subtropical seas.

Habitat. Epilithic in the intertidal and subtidal.

[After Silva & Chacana, Algae of Australia: Mar. Benthic Algae of North-western Australia, 1. Green and Brown Algae 112 (2015)]