Turbinaria ornata
Phaeophyta, Sargassaceae
Authority: (Turner) J. Agardh
Hawaiian name: none
Characteristic feature: Hard, thick alga, with distinctive angular turban-like blades.
Description: Plants erect and stiff, 2-20-(30) cm long when reproductive, usually isolated or in small groups, often rusty brown to dark brown; holdfast bearing one (or more) terete erect portion, basally a conical or irregular holdfast with several unbranched or dichotomously branched stolons, these often remaining when erect portion torn off, or appearing before erect portion formed. Juvenile plants with flattened blades can form new plants, become free-floating; larger plants with several orders of branching. Blades peltate, with 'petiole' and double row of stiff spines often with secondary branching from lower adaxial surface of blades; rarely irregularly triangular margin of leaves in apical view; petiole cylindrical near base, becoming traingularly compressed in distal portions; many plants with some leaves having hollow centers that function as floats. Receptacles developing into tightly branched clusters on adaxial side of leaf petiole near base, mostly cylindrical, to 1.5 cm long, with blunt apices; conceptacles not producing noticeable bumps on receptacle surface; oogonia and antheridia usually produced in same receptacles.
Habitat: Found in a wide variety of habitats including exposed rocky intertidal area, tidepools, intertidal benches, reef flats and in deeper water. Mid intertidal to at least 30 m. Common and sometimes the most abundant large alga on reef flats in waters 2-10 m deep.
Hawaiian distribution: All main Hawaiian Islands, including the Northwestern Hawaiian Islands.
Other: Indigenous to Hawai‘i. Has become invasive in recent times in the South Pacific. Often covered with coralline algae giving it a pink color. The tough thallus of Turbinaria ornata allow it to withstand the high wave energy of the intertidal environment, and to resist herbivory.