Fucus retroflexus Labillardière 1807 Cystophora retroflexa is a brown alga species in the genus Cystophora.

Prefers more sheltered environments compared to other Cystophora species, often found in sheltered reefs from 0 to 12 m in depth.

[3] This species contains phlorotannins of the classes of phlorethols and fucophlorethols (phloroglucinol, difucol, tetraphlorethol-E, pentaphlorethol-B, hexaphlorethol-A, fucotriphlorethol-G, fucotriphlorethol-H, fucotetraphlorethol-J, fucotetraphlorethol-K, fucopentaphlorethol-E, bisfucoheptaphlorethol-A, difucofucotriphlorethol-A, difucofucotetraphlorethol-B, terfucohexaphlorethol-B, terfucoheptaphlorethol-A, diphlorethol, triphlorethol-A, tetraphlorethol-C, fucophlorethol-B, fucodiphlorethol-D, fucotriphlorethol-B, fucotetra-phlorethol-B, bisfucotriphlorethol-A, bisfucotetraphlorethol-A, bisfucopentaphlorethol-A, bisfucopentaphlorethol-B, difucophlorethol-A, difucofucotetraphlorethol-A, terfucopentaphlorethol-A and terfucohexaphlorethol-A).

[4] There are also halogenated phlorethols and fucophlorethols (chlorinated, brominated and iodinated derivatives).

This Phaeophyceae (or brown alga) article is a stub.