Halimeda macroloba Decaisne 1841

    Thalli erect, dark to pale green and moderately calcified, very stiff, branched in a single plane, resulting in a fan shaped appearance, rarely dense, 8 – 13 cm high. Thalli anchored by well-developed bulbous holdfast, 3- 5 cm long and 6-11 mm broad; basal segment unbranched, compressed to cylindrical stipe. Thalli trichotomously branched at the basis and slightly sparse and dichotomous at the apex. The first two basal segments rectangular with slightly expanded anterior portion. Upper segments generally fan-shaped with few reniform, Segments thick, fleshy and largely rounded to reniform.

    Surface of the segments flat to slightly ribbed, upper margin linear to slightly lobed, 10–16 mm long, 13–25 mm wide. Internal structure of the segment exhibit cortex composed of 4 layers of utricles; primary utricles (Surface utricles) elongated 85-110 µm long with large hexagonal outlines in surface view. Secondary utricles elongated 70- 92 µm long and every utricle supports 2-4 primary (surface) utricles. Medulla consists of long interwoven siphons and fused at node into a single unit with a series of pores that less than 20 µm in diameter.