Gracilaria canaliculata

Thallus tough, cartilaginous, 3-7(-30) cm high, greenish, yellowish-red to purple. Main axes and branches commonly cylindrical, 2.5-3 mm in diam. or slightly compressed (to 5 mm width). Branching mostly dichotomous, irregularly dichotomous, alternate, irregular, to 4-5 orders of branches. Axes and branches non-constricted, slightly tapering to bases. Ultimate branchlets simple, with blunt tips. In transverse section, 1-2 rows of small cortical cells to 10 mm high and 5-8 mm broad; medullary cells thin-walled, large, 200-300 mm in diam. and loosely arranged. Terasporangia ovate cruciately divided, 10-15×26 mm. Attachment by basal disk and secondary bundles of rhizoids. Growing on dead corals, stones, in pools, at low intertidal, at sites exposed to wave action.

Indian and Pacific Oceans. Common in the Asian-Pacific Region.