Derbesia attenuata E.Y.Dawson

Scientific Description

Habit and structure. Thallus grass-green, epiphytic, solitary or in small groups, minute, to 1.5 mm tall, attached by a prostrate branched basal siphon to 1.3 mm long and mostly 30–60 µm diam., but tapering to 15 µm diam. in parts; this bearing 1 or 2 erect dichotomously branched axes. Erect axes unconstricted, basally unbranched for 450–550 µm, 45–65 µm diam., then regularly dichotomously branched at narrow angles every 200–350 µm, the siphons tapering gradually to 8–12 µm diam. at the apices. Chloroplasts numerous, spherical to ellipsoidal, 2–5 µm diam., each with a small pyrenoid. Reproduction not seen.

Distribution. Known from several tropical locations in the Indo-West Pacific (including eastern Australia) and Panama, possibly widespread but overlooked due to its small size.

Habitat. Epiphytic in the shallow subtidal.

[After Huisman, Algae of Australia: Mar. Benthic Algae of North-western Australia, 1. Green and Brown Algae 114 (2015)]