Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families, all in the order Alismatales. Seagrasses evolved from terrestrial plants which recolonised the ocean 70 to 100 million years ago.
Seagrass
Zostera marina seedling
Seagrass bed with several echinoids
Seagrass bed with dense turtle grass (Thalassia testudinum) and an immature queen conch (Eustrombus gigas)
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae, commonly called angiosperms. They include all forbs, grasses and grass-like plants, a vast majority of broad-leaved trees, shrubs and vines, and most aquatic plants. The term "angiosperm" is derived from the Greek words ἀγγεῖον / angeion and σπέρμα / sperma ('seed'), meaning that the seeds are enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta.
Image: Ranunculus repens 1 (cropped)
Image: Nymphaea alba flower and leaves DSC 3326w
Image: Meadow Foxtail head
Image: Apple blossom. Eastern Siberia