Rhizophora is a genus of tropical mangrove trees, sometimes collectively called true mangroves. The most notable species is the red mangrove but some other species and a few natural hybrids are known. Rhizophora species generally live in intertidal zones which are inundated daily by the ocean. They exhibit a number of adaptations to this environment, including pneumatophores that elevate the plants above the water and allow them to respire oxygen even while their lower roots are submerged and a cytological molecular "pump" mechanism that allows them to remove excess salts from their cells. The generic name is derived from the Greek words ῥίζα (rhiza), meaning "root," and φορός (phoros), meaning "bearing," referring to the stilt-roots.