Enhalus | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Order: | Alismatales |
Family: | Hydrocharitaceae |
Genus: | Enhalus Rich. [2] |
Species: | E. acoroides |
Binomial name | |
Enhalus acoroides | |
Synonyms [4] | |
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Enhalus is a monotypic genus of marine flowering plants. [5] The sole species is Enhalus acoroides. Enhalus is a large seagrass native to coastal waters of the tropical Indian and Western Pacific Oceans. [5] It is the only species of seagrass that does aerial surface pollination in which the pollen and the styles remain dry. [6] Enhalus is surface pollinated with male flowers that detach from the plant to float on the surface until they reach a female flower where pollination can occur. [5] Enhalus acoroides is considered a slow-growing, "climax" species. [7]
Enhalus acoroides massive rhizomes (1.5 cm in diameter) help it stay anchored in soft mud substrates, withstanding wave action and tidal currents. it has long strap like leaves (30–150 cm) which make up a significant volume of total plant biomass of shallow water seagrass beds, because of the large structure of the leaves and where they are in the water column, they provide greater surfaces for Epibiont organisms to inhabit. [8] Fruit are round and large (4–6 cm in diameter) with dark, ribbed skin and 6-7 white seeds. The male plant bears a single pedunculate inflorescence or stem containing clusters of flowers, each is highly reduced in form to a small free floating device. Female Enhalus acoroides bears only a single inflorescence, but the peduncle of a female flower is much longer. [8]
Enhalus acoroides is a littoral species living in shallow soft substrates like muddy or sand-flats and coral substrates depending the region of growth. It can be found as far east as Papua New Guinea and can range from the Red Sea south to northern Mozambique in the Indian Ocean. [9] It can be found in mixed meadows of seagrasses comprising 90% of the meadow biomass mainly with Thallassia hemprichii. [10] it can also be found living in isolated areas. Enhalus acoroides grows best just above the level of mean low water springs and grows to generally 4 meters deep. [6]
Enhalus acoroides is dioecious and able to reproduce sexually and asexually. [10] Enhalus acoroides create small isolated patches containing 25 to 200 shoots through lateral rhizome spreading. It can also produce pollen like other seagrasses but it is unique in that it is the only species of seagrasses that surface pollinates. During this process, the male flower will break off from the spathe and rise to the surface where it has numerous flowers inside its hydrophobic inflorescences. [10] Once at the surface it will release its pollen to a female inflorescence where it has reached the surface of the water by means of an elongated stalk surface. The developing fruit is drawn under the water to finish ripening. Flowering is a year round phenomenon and the amount of flowers being produced are strongly related to variations in mean water temperatures. [10]
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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.
Cymodoceaceae is a family of flowering plants, sometimes known as the "manatee-grass family", which includes only marine species.
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Phyllospadix scouleri, or Scouler's surfgrass, is a flowering marine plant in the family Zosteraceae. It is native to the coastline of western North America from the Alaskan panhandle to Baja California.
Halophila johnsonii, or Johnson's seagrass, is a small, asexual seagrass in the family Hydrocharitaceae. It occurs only on the southeastern coast of Florida, and was the first marine plant listed on the United States endangered species list, where it is listed as a threatened species. Female flowers have been observed, but even with decade long observational studies, neither male flowers nor seed have ever been observed.
Nymphoides peltata is perennial, rooted aquatic plant with floating leaves of the family Menyanthaceae.
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Thalassia is a marine seagrass genus comprising two known species.
Thalassia testudinum, commonly known as turtlegrass, is a species of marine seagrass. It forms meadows in shallow sandy or muddy locations in the Caribbean Sea and the Gulf of Mexico. Turtle grass and other seagrasses form meadows which are important habitats and feeding grounds. The grass is eaten by turtles and herbivorous fish, supports many epiphytes, and provides habitat for juvenile fish and many invertebrate taxa.
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Cymodocea nodosa is a species of seagrass in the family Cymodoceaceae and is sometimes known as little Neptune grass. As a seagrass, it is restricted to growing underwater and is found in shallow parts of the Mediterranean Sea and certain adjoining areas of the Atlantic Ocean.
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Zostera noltii is a species of seagrass known by the common name dwarf eelgrass. It is found in shallow coastal waters in north western Europe, the Mediterranean Sea, Black Sea, Caspian Sea and Aral Sea and on islands in the Atlantic off the coast of northwest Africa. It is an important part of the intertidal and shallow subtidal ecosystems of estuaries, bays and lagoons.
Halodule uninervis is a species of seagrass in the family Cymodoceaceae. It is native to the western Pacific and Indian Oceans. Common names include narrowleaf seagrass in English and a'shab bahriya in Arabic.
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Zostera muelleri is a southern hemisphere temperate species of seagrass native to the seacoasts of South Australia, Victoria and Tasmania. and New Zealand. Today, Zostera muelleri can be found in regions of Australia, New Zealand, and Papua New Guinea, as well as areas of the eastern Indian Ocean, and the southwest and western central Pacific Ocean. Zostera muelleri is a marine angiosperm, and is commonly referred to as eelgrass or garweed. It is a fast growing and readily colonizing species that serves as a feeding ground for wading birds and aquatic animals, and a breeding ground for juvenile fish and shrimp species.
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