A genus of RED ALGAE in the family Rhodomelaceae. Some species are a rich source of chlorine-and bromine-containing metabolites which show significant antibacterial activity.

Polyketides of up to a few dozen carbons in length, formed by chain extension of multiple PROPIONATES and oxygenated to form tetrahydrofuran and lactone rings along the length of the chain. They are found in ANNONACEAE and other PLANTS. Related compounds cyclize to MACROLIDES.

Multicellular marine macroalgae including some members of red (RHODOPHYTA), green (CHLOROPHYTA), and brown (PHAEOPHYTA) algae. They are widely distributed in the ocean, occurring from the tide level to considerable depths, free-floating (planktonic) or anchored to the substratum (benthic). They lack a specialized vascular system but take up fluids, nutrients, and gases directly from the water. They contain CHLOROPHYLL and are photosynthetic, but some also contain other light-absorbing pigments. Many are of economic importance as FOOD, fertilizer, AGAR, potash, or source of IODINE.