Phylum Anthophyta
The Phylum Anthophyta includes the flowering plants such as seagrass and mangroves. Seagrasses are hydrophytes which means that they usually live underneath the water. Since they are hyrdophytes, they are able to grow, flower, and germinate while fully submerged. Seagrasses are the best adapted to marine environments and out of all aquatic plants are the only ones that are truly marine.
Mangroves are more often trees or shrubs rather than grasses and herbs. Mangroves are not usually submerged by tides and if they are, very little parts of them are. These plants thrive along tropical shores with limited wave action, a low slope, high rates of sedimentation, and soils that are waterlogged, anoxic, and high in salts. They are most often found at low latitudes around the Caribbean Sea, Atlantic Ocean, Indian Ocean, and western and eastern Pacific Ocean.