Halimeda opuntia

Halimeda opuntia (Linnaeus) J.V. Lamouroux
Prostrate sea cactus

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Family:	Halimedaceae ()
Max. size:
Environment:	sessile; marine; depth range 0 - 25 m
Distribution:	Indo-Pacific, Atlantic Ocean and the Mediterranean.
Diagnosis:	Thalli form greenish to cream amorphous clumps, attached by rhizoids at various points where segments get in contact with the substrate. Branches composed of moderately calcified flat segments with a distinct central rib, generally reniform to flabellate with the upper margin entire, sinuate to deeply lobed, 3 to 8 mm high, 4 to 10 mm wide, and 0.5 to 7 mm thick. Cortex consisting of 5 layers of utricles formed by repeated dichotomies from the medullary filaments; outermost utricles adhere slightly after decalcification, hexagonal in surface view, 23 by 40 to 50 μm in transverse section; secondary utricles about 17 μm wide. Central medullary filaments extend along the segments, terete and trichotomously branched, with evident constrictions at a short distance above the point of branching. Amorphous clumps up to 15 cm in diameter (Ref. 80758).
Biology:	Not utilized commercially, although found to be a source of growth regulators such as auxin, gibberellin, cytokinin; has antibacterial and antifungal properties (Ref. 80758). Grows in the lower intertidal zone of coral reefs or on dead corals below the low-tide mark in calm shallow waters (Ref. 80758).
IUCN Red List Status:	Not Evaluated (N.E.) Ref. 123251)
Threat to humans:
Country info:

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