The Alismatales (alismatids) are an order of flowering plants including about 4,500 species. Plants assigned to this order are mostly tropical or aquatic. Some grow in fresh water, some in marine habitats. Perhaps the most important food crop in the order is the corm of the taro plant, Colocasia esculenta.
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.
Hydrocharitaceae is a flowering plant family including 16 known genera with a total of ca 135 known species, that including a number of species of aquatic plant, for instance the tape-grasses, the well known Canadian waterweed, and frogbit.
The Buxaceae are a small family of six genera and about 123 known species of flowering plants. They are shrubs and small trees, with a cosmopolitan distribution. A seventh genus, sometimes accepted in the past (Notobuxus), has been shown by genetic studies to be included within Buxus.
Zostera is a small genus of widely distributed seagrasses, commonly called marine eelgrass, or simply seagrass or eelgrass, and also known as seaweed by some fishermen and recreational boaters including yachtsmen. The genus Zostera contains 15 species.
Zosteraceae is a family of marine perennial flowering plants found in temperate and subtropical coastal waters, with the highest diversity located around Korea and Japan. Most seagrasses complete their entire life cycle under water, having filamentous pollen especially adapted to dispersion in an aquatic environment and ribbon-like leaves that lack stomata. Seagrasses are herbaceous and have prominent creeping rhizomes. A distinctive characteristic of the family is the presence of characteristic retinacules, which are present in all species except members of Zostera subgenus Zostera.
Juncaginaceae is a family of flowering plants, recognized by most taxonomists for the past few decades. It is also known as the arrowgrass family. It includes 3 genera with a total of 34 known species.
Myrothamnus is a genus of flowering plants, consisting of two species of small xerophytic shrubs, in the southern parts of tropical Africa and in Madagascar. Myrothamnus is recognized as the only genus in the family Myrothamnaceae.
Dasypogonaceae is a family of flowering plants based on the type genus Dasypogon, one that has traditionally not been commonly recognized by taxonomists; the plants it contains were usually included in the family Xanthorrhoeaceae. If valid, Dasypogonaceae includes four genera with 16 species. The family is endemic to Australia. The best known representative is Kingia australis.
A seagrass meadow or seagrass bed is an underwater ecosystem formed by seagrasses. Seagrasses are marine (saltwater) plants found in shallow coastal waters and in the brackish waters of estuaries. Seagrasses are flowering plants with stems and long green, grass-like leaves. They produce seeds and pollen and have roots and rhizomes which anchor them in seafloor sand.
Ixiolirion is a genus of flowering plants native to central and southwest Asia, first described as a genus in 1821. Recent classifications place the group in the monogeneric family Ixioliriaceae in the order Asparagales of the monocots. In earlier systems of classification, it was usually placed in the family Amaryllidaceae.
Cymodoceaceae is a family of flowering plants, sometimes known as the "manatee-grass family", which includes only marine species.
The Joinvilleaceae are a family of flowering plants with a single genus including four species. The APG II system, of 2003 assigns it to the order Poales in the clade commelinids in the monocots. The family consists of one genus with four currently accepted species, distributed from the Malay Peninsula to the Caroline Islands and high islands in the Pacific Ocean. It is evolutionarily significant as a relictual group closely related to grasses. They closely resemble large grass plants, in both general appearance and microanatomy, but possess fleshy fruits.
Posidonia australis, also known as fibre-ball weed or ribbon weed, is a species of seagrass that occurs in the southern waters of Australia. It forms large meadows important to environmental conservation. Balls of decomposing detritus from the foliage are found along nearby shore-lines.
Posidonia ostenfeldii is a species of seagrass that occurs in the southern waters of Australia.
Posidonia oceanica, commonly known as Neptune grass or Mediterranean tapeweed, is a seagrass species that is endemic to the Mediterranean Sea. It forms large underwater meadows that are an important part of the ecosystem. The fruit is free floating and known in Italy as "the olive of the sea". Balls of fibrous material from its foliage, known as egagropili or Neptune balls, wash up to nearby shorelines.
Posidonia coriacea is a species of seagrass that occurs in the southern waters of Australia.
The Seagrasses of Western Australia are submerged flowering plants found along the coast, around islands, and in Estuaries of Western Australia. The region contains some of the largest seagrass meadows in the world, and is the most diverse in the number of species. The variety of habitats along its western and southern coasts is often soft sands in shallow subtropical waters, ideal for these plants.
Posidonia robertsoniae is one of the seagrasses of Western Australia, submerged flowering plants that occur in the southern coastal waters.
Zostera novazelandica Setchell is a species of seagrass in the family Zosteraceae found on the shores of New Zealand. It is regarded as a distinct species by some authors but considered as a synonym of Zostera muelleri Irmisch ex Ascherson by others. The Maori names for Zostera novazelandica are karepō, nana, rehia, and rimurehia.
