Table 4.

Floating weeds and their Beneficial effects collected from literature.

Habit and habitat	Beneficial effects	Sourcess
1. Azolla pinnata R.Br.
Free floating, hetersporous, small aquatic fern	Hg pollution is a matter of serious concern. A marked reduction in the content of chlorophyll a, protein, DNA and RNA occurs due to toxicity imposed by Hg. A. pinnata can remove Hg from industrial effluents by accumulating Hg more efficiently and is thus recommended for removal of Hg from contaminated waters.	Rai ' Tripathi 2009.
	Sewage effluents for cultivation of A. pinnata are evaluated so that the biomass production can be used for different applications as well as recycle wastewater. The study has recommended that cultivation of A. pinnata can facilitate wastewater management through recycling and reuse of municipal wastewater and is a fruitful strategy for sustainable and ecofriendly agriculture	Rai and Kumar, 2007
	The absorption of iron, copper, cadmium, nickel, lead, zinc, manganese and cobalt by A. pinnata and subsequent utilization of this biomass for production of biogas (methane), have been investigated.	Jain et al., 1992
	A. pinnata has fame as a promoted component of rice culture in China because of the nitrogen fixing symbiotic bacteria that live in its leaves.	Pemberton and Bodle, 2009
2. Lemna aequinoctialis Welw. (Syn. L. paucicostata Hegelm.)
Annual, often forms floating mats on the surface of still or slowly flowing water.	The duckweeds are important in the process of bioremediation because they grow rapidly, absorbing excess mineral nutrients, particularly nitrogen and phosphates. A cover of duckweeds can reduce evaporation of water compared to a clear surface.	Robil, 2010.
	Lemna is recommended for assessing the toxicity of textile dye wastewaters	Sharma et al., 2005
3. Lemna gibba Linn.
Annual, often forms floating mats on the surface of still or slowly flowing water.	It has been investigated that L. gibba can significantly accumulate the toxic elements, arsenic, uranium, and boron. So, it can be used as a practical and effective method to remove toxic elements from waste water.	Sasmaz and Obek, 2009.
	Duckweeds are important food source for waterfowl. Some duckweeds are used in freshwater aquariums and ponds. The plants can provide nitrate removal (if cropped).	Robil, 2010.
4. Marsilea quadrifoliata Linn.
Perennial, floating fern, rooted at the bottom of the soil.	It can be used for lack of breast milk after childbirth. The whole plant of M. quadrifoliata including roots is crushed with whole plant of Centella asiatica including roots and made into a paste. The paste is applied twice daily for 7 days around the nipple.	Nawaz, 2009
	Whole plant paste is soaked in hot water and is used for toothache.	Anisuzzaman et al., 2007
5. Nelumbo nucifera Gaerth. (Syn. N. speciosum Willd; Nelumbium nelumbo (L.) Druce)
Perennial, rooted in the soil, floating	The extracts of rhizomes, seeds, flowers and leaves have been reported to have varied therapeutic potential. Several bioactive compounds have been derived from these plant parts belonging to different chemical groups, including alkaloids, flavonoids, glycosides, triterpenoid, vitamins etc.,	Mukherjee et al., 2010
	Tender rhizomes, stems and leaves of lotus are edible and its seeds are rich in protein as well as minerals. Petals are useful as garnish, while the stamens are used in flavoring the tea and the roasted seeds can be used as coffee substitute. Powdered popped seeds are eaten dry and useful in bread preparation. Seeds are raw material for Ayurvedic and folk medicines to treat many ailments such as tissue inflammation, cancer, diuretics, skin diseases and as poison antidote. Lotus plants provide several bioactive ingredients like alkaloids, flavonoids, antioxidants, antisteroids, antipyretic, anticancerous, antiviral and anti-obesity properties.	Sridhar and Bhat, 2007.
6. Nymphoides cristata (Roxb.) Ketze. (Syn. Menyanthes cristata Roxb.)
Annual, with long floating stem, rooting at the nodes, leaves floating	The hepatoprotective effect of N. cristatum was investigated in an experimental model. The albino rats were treated with 50 percent ethanol extract of the whole plant and callus of N. cristatum extracts at a dose of 500 mg/kg body weight orally. These results evidence/demonstrated that N. cristatum has a protective effect against experimental liver damage.	Niranjan et al., 2010.
7. Nymphoides indica (L.) Kuntze (Syn: Menyanthes indica L.)
Annual, with long floating stem, rooting at the nodes, leaves floating	Plant paste is applied as bandage in cut and injuries as coolant and for early healing. Dried rhizome paste along with little honey is taken in diuresis.	Jain et al., 2007
	Whole plant juice (20–35ml) is taken on empty stomach twice daily for a week, for curing fever and jaundice in India.	Das et al., 2005
8. Pistia stratiotes Linn.
Perennial, stemless, free floating herb with rosette of leaves.	Nutrients such as N and P can be removed from wastewater by P. stratiotes.	Olguin and Gloria, 2010
	Plant paste is applied in boils and burns.	Jain et al., 2007
	Leaves are used in the traditional medicine for the treatment of ring worm infection of the scalp, syphilitic, eruption, skin infection, boils and wound. The oil extract is in the treatment of worm infestation, tuberculosis, asthma, dysentery, and externally applied to treat skin diseases, inflammations piles, ulcers, syphilitic infections and burns.	Premkumar and Shyamsudar, 2005
	The results of one study indicated that P. stratiotes methanolic extract was the most active against the dermatophytes, Trichophyton rubrum, T. mentagrophytes and Epidermophyton floccosum.	Premkumar and Shyamsudar, 2005
	The ethanolic extract of the plant P. stratiotes was investigated for activity against Indian earthworms Pheretima posthuma and nematode Ascardi galli. The study indicated the potential usefulness of P. stratiotes against earthworm infections.	Kumar et al., 2010
	Arsenate uptake by aquatic plant water lettuce (Pistia stratiotes L.) was studied in the laboratory condition to investigate a low cost natural aquatic treatment system for pollutant removal. The removal efficiency was, however, noted to be maximum (87.5%). The effect of biomass quantity has also been investigated along with some metabolic parameters.	Mukherjee and Kumar, 2005
9. Potamogeton nodosus Poiret
Perennial, rooted with both floating and underwater leaves,	2-Hydroxyheptane-3,5-dione was obtained from the petrol soluble fraction (PE) of the ethanol extract of P. nodosus. Biological screening of PE revealed antibacterial activity and cytotoxicity. Compound showed only antibacterial activity.	Alam et al., 1999
	A new furanoid diterpene, 15,16-epoxy-12-oxo-8(17),13(16),14-labdatrien-20,19-olide was isolated from an ethanolic extract of P. nodosus. Its structure was elucidated by the usual spectroscopic methods, including 2D NMR techniques. Compound was found to exhibit moderate inhibitory activity against a number of both Gram-positive and Gram-negative bacteria.	Qais et al., 1998
	Provides important food and cover for aquatic animals. Tubers of long-leaf pondweed are an important waterfowl food.	Hamel et al., 2001
10. Ricciocapus natans (Linn.) Corda (Syn. Riccia natans Linn.)
Free floating, liver wort, growing with Lemna spp., Spirodela sp.	Food for ducks and birds; provides habitat for aquatic insects and invertebrates.	Hamel et al., 2001
11. Spirodela polyrrhiza (Linn.) Schleid. (Syn. Lemna polyrrhiza Linn.)
Annual, free floating, Often grows with other member of Lemnaceae.	S. polyrhiza shows profound ability to take up Cd from ambient medium.	Noraho, and Gaur, 1996.
	S. polyrhiza is recommended for assessing the toxicity of textile dye wastewaters.	Sharma et al., 2005
	Provides a high protein food source for ducks and geese, also eaten by certain fish. In Africa and Asia, giant duckweed has been harvested for cattle and pig feed. Has been used to reduce nutrients in sewage effluent.	Hamel et al., 2001
	Duckweeds are important food source for waterfowl. Some duckweeds are used in freshwater aquariums and ponds. The plants can provide nitrate removal (if cropped). The plants are used as shelter by pond water species, such as bullfrogs and bluegills. The duckweeds are important in the process of bioremediation because they grow rapidly, absorbing excess mineral nutrients, particularly nitrogen and phosphates. A cover of duckweeds can reduce evaporation of water compared to a clear surface.	Robil, 2010.