Derbesia tenuissima (Moris & De Not.) P.Crouan & H.Crouan

Scientific Description

Habit and structure. Thallus dark green, to 10 mm tall, tufted, arising from a matted irregularly lobed rhizoidal base, bearing many erect sparsely branched siphons, to 120 µm diam. near the base, tapering to 50 µm diam. near apices; siphons with occasional double septa at bases of lateral branches. Chloroplasts numerous, subspherical to lenticular, 5–8 µm diam., each with a pyrenoid. Sporangia obovoid or pyriform, to 175 µm long (including pedicel), 110–120 µm diam., with a short pedicel and double septa at the base.

Distribution. Widespread in the north-eastern Atlantic Ocean, the Mediterranean Sea, the Indian Ocean and the Pacific Ocean.

Habitat. Epilithic.

[After Huisman, Algae of Australia: Mar. Benthic Algae of North-western Australia, 1. Green and Brown Algae 116 (2015)]