The alismatid monocots are a group of 15 interrelated families of flowering plants, named for their largest order, Alismatales.[a] Like other monocots, they usually have a single embryonic leaf (cotyledon) in their seeds, scattered vascular systems, leaves with parallel veins, flowers with parts in threes or multiples of three, and roots that can develop in more than one place along the stems.[6] The alismatids have adapted to thrive in oceans, temperate zones, deserts, the tropics, and even glacial regions.[7]
Like the earliest monocots, many of the alismatid monocots are aquatic, and some grow completely submerged. Apart from the sweet-flag family of wetlands plants, all the alismatid families are in Alismatales. Some of the plants in this order are invasive aquatic weeds that can disrupt and destabilize ecosystems. Others grow in a variety of habitats, especially plants in the aroid family. This family includes the titan arum, with the world's largest unbranched inflorescence, and also the world's smallest flowering plant, duckweed.[2][5][8][9]
Herbaceous latex-bearing aquatic plants, usually perennials. They take root in freshwater beds, and some remain submerged.[19][24] Two species are consumed in Asia, and another was a food source for Native Americans.[19][24]C4 photosynthesis[d] has been observed in Sagittaria.[8]
1 genus, in Africa, Oceania, and South and Southeast Asia[25][27]
Herbaceous smooth-stemmed freshwater perennials, usually with long leaf-stalks.[28]Cape pondweed flowers are consumed as a delicacy in South Africa; the tubers are also edible.[25]
142 genera, worldwide, especially in the tropics[33][34]
Generally sappy, herbaceous plants growing in soil, in water and on trees, along with a few woody climbers. Many cultures have relied on taro plants (which are toxic when raw) as a staple crop.[33][35]
Smooth-stemmed herbaceous aquatic, swamp or marsh plants, usually with milky latex.[40] They are consumed in parts of Russia, in bread or as a vegetable.[36]
6 genera, in tropical and warm temperate seas[41][44]
Large perennials,[41] up to 30 cm (12 in) long in the genus Cymodocea.[45] They nourish and shelter many crustaceans and fish that are harvested commercially.[41]
Annual and perennial aquatic plants. One species is consumed in Asia. Many invasive genera have become entrenched, causing considerable economic damage.[46]
1 genus, in the Mediterranean and oceans south and west of Australia[57][59]
Submerged plants with long linear leaves. Genetically identical beds of Posidonia oceanica in the Mediterranean can be kilometers wide and persist for many thousands of years.[57]
2 genera, in temperate and subtropical sea beds[76][78]
Perennials with simple leaves.[76][79] The plants have been used as packing material. The dense growths support commercially important fish and shrimp.[76]
Some of POWO's data originally appeared in different databases. On the page for each family, these databases (if any) will appear under the "General information" tab.
Christenhusz, Maarten; Fay, Michael Francis; Chase, Mark Wayne (2017). Plants of the World: An Illustrated Encyclopedia of Vascular Plants. Chicago, Illinois: Kew Publishing and The University of Chicago Press. ISBN978-0-226-52292-0.
Coombes, Allen (2012). The A to Z of Plant Names: A Quick Reference Guide to 4000 Garden Plants. Portland, Oregon: Timber Press. ISBN978-1-60469-196-2.
IPNI (2022). "International Plant Names Index". London, Boston and Canberra: Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; and the Australian National Botanic Gardens. Retrieved October 21, 2022.