PIIST
Growth form
Broadleaf
Biological cycle
Vivacious
Habitat
Aquatic
synonym | Apiospermum obcordatum (Schleid.) Klotzsch |
synonym | Limnonesis commutata (Schleid.) Klotzsch |
synonym | Limnonesis friedrichsthaliana Klotzsch |
synonym | Pistia aegyptiaca Schleid. |
synonym | Pistia aethiopica Fenzl ex Klotzsch |
synonym | Pistia africana C.Presl |
synonym | Pistia amazonica C.Presl |
synonym | Pistia brasiliensis Klotzsch |
synonym | Pistia commutata Schleid. |
synonym | Pistia crispata Blume |
synonym | Pistia cumingii Klotzsch |
synonym | Pistia gardneri Klotzsch |
synonym | Pistia horkeliana Miq. |
synonym | Pistia leprieuri Blume |
synonym | Pistia linguiformis Blume |
synonym | Pistia minor Blume |
synonym | Pistia natalensis Klotzsch |
synonym | Pistia obcordata Schleid. |
synonym | Pistia occidentalis Blume |
synonym | Pistia schleideniana Klotzsch |
synonym | Pistia spathulata Michx. |
synonym | Pistia stratiotes var. cuneata Engl. |
synonym | Pistia stratiotes var. linguiformis Engl. |
synonym | Pistia stratiotes var. obcordata (Schleid.) Engl. |
synonym | Pistia stratiotes var. spathulata (Michx.) Engl. |
synonym | Pistia texensis Klotzsch |
synonym | Pistia turpini Blume |
synonym | Pistia turpinii K.Koch |
synonym | Pistia weigeltiana C.Presl |
synonym | Zala asiatica Lour. |
Chinese |
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Creoles and pidgins; French-based |
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Créole Maurice |
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Créole Réunion |
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Créole Seychelles |
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English |
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French |
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Italian |
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Malgache |
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Other |
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Portuguese |
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Spanish; Castilian |
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Global description
Pistia stratiotes is a floating plant, drifting, without stem, formed of a leaf rosette, 5 to 25 cm in diameter and with short runners giving rise to daughter plants. A large network of fibrous roots dangles underwater. The leaves are in dense rosette, sessile, broadly spatulate, fleshy, and composed of a floating airy tissue. Both sides are hairy, greyish or yellowish green. Flowers are numerous, small and hidden at the base of the leaves, surrounded by a small pale green or white leafy structure, 7 mm long. The fruits are small elongated berries, 6 to 10 mm long, containing several dark seeds.
First leaves
First leaves are rounded or obovate, slightly stalked, prostrate at the surface of water, 1 to 2 mm in diameter. The black seed remains attached to the seedling for some time.
General habit
It is a floating aquatic plant, drifting, without stem, with spathulate leaves forming a dense rosette,3 to 15 cm in height and 5 to 25 cm in diameter, quickly stoloniferous.
Underground system
Many fasciculate fibrous roots, pendulous, measuring up to 50 cm long, with multiple perpendicular rootlets.
Stem
The stem is reduced to indistinct tillage plate at the base of the leaves. Lateral stolons are present, extending from the base of the leaves, cylindrical, 1 to 5 mm in diameter, depending on the size of the mother plant, at the end of which thrive the daughter plants. These stolons appear at the stage of 3 to 4 leaves of young plants from germination.
Leaf
The leaves are simple, alternate, sessile, spongy, and with dense spiral rosette. The lamina is spatulate, obovate with a rounded to truncate apex and a wedged base, 6 to 12 cm long and 3 to 6 cm wide, with 5 to 7 (13) sub-parallel veins, especially salient to the underside. The upper surface is green and tomentose while the underside is paler with denser tomentum.
Inflorescence
The inflorescence is small, hidden by the leaves, carried by a very short peduncle, about 4 mm long. It is formed by a whitish spathe,5 to 25 mm long, persistent, smooth inside and tomentose on the outside, forming two cavities.
Flower
The flower consists of a whitish spathe, 5 to 25 mm long, persistent, glabrous inside and tomentose outside, forming two cavities. There is a very reduced spadix inside, attached to the base of the spathe, with one female flower in the lower cavity, without perianth and 2 to 8 apical male flowers in the upper cavity, inserted on a whorl axis sub-tended by a shallow cup. The male flowers are reduced by 2 fused stamens. The female flowers are solitary, reduced to an ovoid unilocular ovary, inserted through the axis of the spadix, a loculus with several sessile ovules. The style is short, slightly curved towards the axis, topped with a globular stigma.
Fruit
The fruit is an ellipsoid berry, 6 to 10 mm long and 3 to 6 mm wide, thin-walled, containing 4 to 12 seeds.
Seed
Ovoid or oblong seed, about 2 mm long and 1 mm wide, with truncated apex and depressed disk-shaped. Integument rough, dark brown.
Attributions | Wiktrop |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
Mayotte: Pistia stratiotes flowers from December to February and fruits in February.
Attributions | Wiktrop |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
Attributions | Wiktrop |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
A common aquatic weed that occurs in still water, ponds and pools or in slow flowing rivers and streams in East and West Africa
Pistia stratiotes is a floating plant in fresh water, pH 4. Optimum temperature 22-30 ° C [15-35], enjoys high levels of N, P, and K in the water.
Brazil: Pistia stratioites is a warm to temperate climate plant. It tolerates a wide range of environmental conditions but does not tolerate frost. In Brazil, it thrives in aquatic environments in all regions.
China: Found in lakes and ponds in tropical and subtropical regions.
Comoros: Absent.
French Guiana: Pistia stratiotes can be found in the canals of the Mana rice polder.
Madagascar: floating aquatic species, drift, which grows on stagnant or slow-flowing rivers, lakes and canals, sometimes forming real mattresses on the surface of the water. It is found mainly in humid zones, across the eastern side of the island and the Sambirano, up to 1400 m altitude. Its presence is relatively limited in the western lowlands.
Mauritius: Plant naturalized in rivers, ponds and some during calm water.
Mayotte: Pistia stratiotes is not very frequent. It is naturalized in the Combani reservoir and in urban areas (basin, drainage channels).
Nicaragua: A common species, found in flooded sites in evergreen and deciduous forests in the Pacific zone and on the Rio San Juan, at altitudes of 0 to 1260 m.
Reunion: Species very abundant in all bodies of fresh water shoreline of the island. It is usually mixed with Eichhornia crassipes (Mart.) Solms.
Seychelles: Species occasionally present in marshy areas.
West Indies: Pistia stratiotes is found in ponds and canals. It is sometimes grown as an ornamental in water features and garden ponds.
Attributions | Wiktrop |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
Origin
Pistia stratiotes has uncertain origin, probably native to South America (Rivers, 2002).
Attributions | dummy |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY_SA |
References |
Global harmfulness
Pistia stratiotes prevents browsing, blocking dams, hampers access to water for livestock and people as well as fishing, blocking the pumps, intercepts the light, reduces the oxygen content increases from February to August After the evaporation of a free water surface, upsets the mineral balance, strong release of H2S. According to Rivers (2002), P. stratiotes can inflict a severe impact on the environment and economy of infested areas. The dense mats created by connected rosettes of the plant lead to the majority of problems encountered with water lettuce. These mats can have a negative economic effect by blocking waterways, thus increasing the difficulty of navigation and hindering flood control efforts. Mats of P. stratiotes can also disrupt natural ecosystems. They can lead to a lower concentration of oxygen in covered waters and sediments by blocking airwater interface and root respiration. Extremely thick mats of P. stratiotes can prevent sunlight from reaching underlying water. The cumulative effect of these negative characteristics of the plant is a loss of biodiversity in invaded habitats. P. stratiotes mats can also serve as a breeding place for mosquitoes.
Attributions | Wiktrop |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
Attributions | |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
Global control
Mechanical control: Mechanical control against Pistia stratiotes can be achieved in different ways - manual harvest to the net and at the fork from the shore, harvesting treadmill, harvest by harvester boat. This type of harvesting requires a piling on the bank followed by an evacuation by truck to another location or biomass will be left to rot. Given the speed of propagation of the water lettuce and the amount of biomass produced, this group of methods never allowed to fight effectively against an invasion by these species. These methods require a very large workforce and have a very high energy cost (carpets, boats, trucks) to be permanent. The only cases where these methods are maintained concerning the release of dams and water intakes of hydropower stations, catch water pumps water supply and the input channels and output port on large lakes and large rivers. Given the biomass produced and the growth rate provide for removal of 20 kg / m² every 10 to 15 days.
Chemical control: In France, only two molecules are approved for weed control of aquatic and semi-aquatic plants: efficient dichlobenil on monocots and dicots (80 to 160 kg.ha-1 pc depending on the water depth) Note that this product poses a risk of poisoning for high dose fish; glyphosate for the destruction of semi-aquatic plants helophytes (2160 g.ha-1 3240 until my g.ha-1 for my mallet). But the brutal and kills all water lettuce translates into a huge mass of organic matter flowing and breaks down at the same time, which results in a significant release of H2S in the middle.
Biological control: A weevil is proposed for the biological control against P. stratiotes. These are: Neohydronomus affinis Hustache (Coleoptera: Curculionidae, Erirhinae).
For weeding Advice floating aquatic weeds of irrigated rice and lowland in Africa visit: http://portal.wiktrop.org/document/show/22
Attributions | |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
Attributions | |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Pistia%2520stratiotes
Attributions | |
Contributors | |
Status | UNDER_CREATION |
Licenses | CC_BY |
References |
Root | Root |
Kingdom | Plantae |
Phylum | Tracheophyta |
Class | Liliopsida |
Order | Alismatales |
Family | Araceae |
Genus | Pistia |
Species | Pistia stratiotes L. |