Ulva clathrata

Thallus tubular, soft, flaccid, bright-, light-green, 0.5-4.5(-40) cm high, abundantly branched throughout, forms dense tufts or mats. Main axis multiseriate, tapering gradually towards the apex. Branches initially uniseriate becoming multiseriate below, cylindrical, hollow. Cells in surface view rectangular, quadrangular, rounded polygonal, 20-30 mm wide, 25-40(-53) mm long, in longitudinal rows in narrow branches, sometimes in transverse rows in the uppermost portions of branches and unordered near the base and in mature plants. Pyrenoids 2-4(-4-8) per cell. Attachment by discoid holdfast composed of descending rhizoidal cells. Growing on middle and low intertidal hard substrate.

Tropical to temperate latitudes of Atlantic, Indian and Pacific Oceans. Antarctic and subantarctic Islands.