Agaricia agaricites

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Agaricia agaricites, commonly known as lettuce coral or tan lettuce-leaf coral, is a small colonial stony coral in the family Agariciidae. It lives in shallow tropical waters of the western Atlantic and Caribbean, including the Gulf of Mexico, Florida, the Bahamas, and Brazil, as well as some Atlantic islands. It is found in fore- and back-reef areas, channels, lagoons, and seagrass meadows down to about 75 meters.

Colonies start as encrusting patches and then develop vertical lobes, leaf-like plates, or irregular sheets. The corallites form long, meandering rows, with up to 36 septa and a central spongy columella in each. They are brown or purplish-brown in color. This coral hosts tiny, photosynthetic algae called zooxanthellae, which provide about 70–95% of its energy; the rest comes from plankton caught by the polyps at night.

A. agaricites is common and can be a dominant coral in some areas, but it does not contribute much to reef building and is sometimes considered a “coral weed.” It is vulnerable to bleaching; in 1997, during a hot El Niño event off Brazil, about 80% of colonies bleached, and recovery was slow. The species is listed as Vulnerable by the IUCN, though some areas report it as apparently secure. It can spread quickly after disturbances, as seen in the US Virgin Islands when sediment wiped out a section of the fore-reef and the coral rapidly covered most of the area.