Nymphaea nouchali

Nymphaea nouchali, often known by its synonym Nymphaea stellata, or by common names blue lotus, star lotus, red water lily, blue water lily, blue star water lily or manel flower is a water lily of genus "Nymphaea". It is native to southern and eastern parts of Asia, and is the national flower of Bangladesh and Sri Lanka. In Sanskrit it is "utpala". This species is usually considered to include the blue Egyptian lotus "N. nouchali" var. "caerulea". In the past, taxonomic confusion has occurred, with the name "Nymphaea nouchali" incorrectly applied to "Nymphaea pubescens".
Distribution and habitat.
This aquatic plant is native in a broad region from Afghanistan, the Indian subcontinent, to Taiwan, southeast Asia, and Australia. It has been long valued as a garden flower in Thailand and Myanmar to decorate ponds and gardens. In its natural state, "N. nouchali" is found in static or slow-flowing aquatic habitats of low to moderate depth.
Description.
"N. nouchali" is a day-blooming nonviviparous plant with submerged roots and stems. Part of the leaves are submerged, while others rise slightly above the surface. The leaves are round and green on top; they usually have a darker underside. The floating leaves have undulating edges that give them a crenellated appearance. Their size is about 20–23 cm and their spread is 0.9 to 1.8 m.
This water lily has a beautiful flower which is usually violet blue in color with reddish edges. Some varieties have white, purple, mauve, or fuchsia-colored flowers, hence its name red and blue water lily. The flower has four or five sepals and 13-15 petals that have an angular appearance, making the flower look star-shaped from above. The cup-like calyx has a diameter of 11–14 cm.
Symbolism.
It was also the National flower of the former defunct Hyderabad State. 
"N. nouchali" is the national flower of Bangladesh. A pale blue-flowered "N. nouchali" is the national flower of Sri Lanka, where it is known as "nil mānel" or "nil mahanel" ().
In Sri Lanka, this plant usually grows in buffalo ponds and natural wetlands.
Its beautiful aquatic flower has been mentioned in Sanskrit, Pali, and Sinhala literary works since ancient times under the names "kuvalaya", "indhīwara", "niluppala", "nilothpala", and "nilupul" as a symbol of virtue, discipline, and purity. Buddhist lore in Sri Lanka claims that this flower was one of the 108 auspicious signs found on Prince Siddhartha's footprint. It is said that when Buddha died, lotus flowers blossomed everywhere he had walked in his lifetime.
Claire Waight Keller included the plant to represent Sri Lanka in Meghan Markle's wedding veil, which included the distinctive flora of each Commonwealth country.
"N. nouchali" might have been one of the plants eaten by the Lotophagi of Homer's "Odyssey".
Uses.
"N. nouchali" is used as an ornamental plant because of its spectacular flowers, and is most commonly used for the traditional and cultural festivals in Sri Lanka. It is also popular as an aquarium plant under the name "dwarf lily" or "dwarf red lily". Sometimes, it is grown for its flowers, while other aquarists prefer to trim the lily pads, and just have the underwater foliage.
"N. nouchali" is considered a medicinal plant in Indian Ayurvedic medicine under the name "ambal"; it was mainly used to treat indigestion. 
Like all water lilies, its pear-shaped, brown cottony-covered, potato-sized rhizomes, leaves and most of the plant are poisonous, and contain an alkaloid called nupharin. Unlike European species, this can (and must) be neutralised in the rhizomes of this species by boiling. In India these have been eaten as a famine food or as a medicinal. In Vietnam it was eaten roasted. In Sri Lanka it was formerly eaten as a type of medicine and its price was too high to serve as a normal meal, but in the 1940s some villagers began to cultivate the water lilies in the paddy fields left uncultivated during the monsoon season (Yala season), and the price dropped. It is eaten boiled and in curries. The tubers of this species are completely edible, during the dry season they consist almost entirely of starch, and were eaten in West Africa, usually boiled or roasted.
The dried plant is collected from ponds, tanks, and marshes during the dry season and used in India as animal forage.