Codium arabicum Kütz.

Scientific Description

Habit and structure. Thallus dorsiventral, applanate, to 12 cm wide, plane and tightly adherent to the substratum when young, becoming convoluted with age and finally developing orbicular foliose isobilateral excrescences 1–3 cm diam. Utricles dissecting out into groups resulting from direct production of new utricles from parent utricles; ultimate utricles often failing to produce medullary filaments; mature utricles mostly 500–800 (–1000) µm long, 60–145 µm diam., with subtruncate to slightly rounded apices; utricular wall 1.5–2.0 µm thick, to 12 µm thick at the apices. Hairs (or hair scars) abundant on older utricles, borne in 1–3 irregular whorls in a zone 70–145 µm below the apex. Medullary filaments 20–30 µm diam. Gametangia usually stoutly fusiform, occasionally ovate, 180–300 µm long, 70–130 µm diam., borne on short pedicels 1–3 per utricle in a zone 225–325 µm below the apex of the utricle.

Distribution. Widespread in the Indo-Pacific.

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 105 (2015)]