While all modern plant taxonomy systems agree that this species belongs in the genus Nelumbo, the systems disagree as to which family Nelumbo should be placed in, or whether the genus should belong in its own unique family and order.
The lotus is often confused with the water lilies (Nymphaea, in particular Nymphaea caerulea "blue lotus"). In fact, several older systems, such as the Bentham & Hooker system (which is widely used in the Indian subcontinent) call the lotus Nymphaea nelumbo or Nymphaea stellata. This is, however, evolutionarily incorrect. Far from being in the same family, Nymphaea and Nelumbo are members of different orders (Nymphaeales and Proteales, respectively). Adding to the confusion, some sources have used the scientific name Nymphaea stellata for another species called Blue Lotus or nil mānel in Sinhalese, which is the national flower of both Sri Lanka and Bangladesh.
The roots of lotus are planted in the soil of the pond or river bottom, while the leaves float on top of the water surface or are held well above it. The flowers are usually found on thick stems rising several centimeters above the leaves. The plant normally grows up to a height of about 150 cm and a horizontal spread of up to 3 meters, but some unverified reports place the height as high as over 5 meters. The leaves may be as large as 60 cm in diameter, while the showy flowers can be up to 20 cm in diameter.
Researchers report that the lotus has the remarkable ability to regulate the temperature of its flowers to within a narrow range just as humans and other warmblooded animals do. Dr. Roger S. Seymour and Dr. Paul Schultze-Motel, physiologists at the University of Adelaide in Australia, found that lotus flowers blooming in the Adelaide Botanic Gardens maintained a temperature of 30–35 °C (86–95 °F), even when the air temperature dropped to 10 °C (50 °F). They suspect the flowers may be doing this to attract coldblooded insect pollinators. The study, published in the journal Nature, is the latest discovery in the field of thermoregulation, heat-producing, plants. Two other species known to be able to regulate their temperature include Symplocarpus foetidus and Philodendron selloum.
An individual lotus can live for over a thousand years and has the rare ability to revive into activity after stasis. In 1994, a seed from a sacred lotus, dated at roughly 1,300 years old ± 270 years, was successfully germinated.
As mentioned earlier, the traditional Sacred Lotus is only distantly related to Nymphaea caerulea, but possesses similar chemistry. Both Nymphaea caerulea and Nelumbo nucifera contain the alkaloids nuciferine and aporphine.
The genome of the sacred lotus was sequenced in May 2013.
The distinctive dried seed heads, which resemble the spouts of watering cans, are widely sold throughout the world for decorative purposes and for dried flower arranging.
The flowers, seeds, young leaves, and "roots" (rhizomes) are all edible. In Asia, the petals are sometimes used for garnish, while the large leaves are used as a wrap for food, not frequently eaten (for example, as a wrapper for zongzi). In Korea, the leaves and petals are used as a tisane. Yeonkkotcha (연꽃차) is made with dried petals of white lotus and yeonipcha (연잎차) is made with the leaves. Young lotus stems are used as a salad ingredient in Vietnamese cuisine. The rhizome (called ǒu (藕) in pinyin Chinese, ngau in Cantonese, Nelum Ala (නෙළුම් අල) in Sinhala, thambou in Meitei, kamal kakri in Hindi, renkon (レンコン, 蓮根) in Japanese, and yeongeun (연근) in Korean) is used as a vegetable in soups, deep-fried, stir-fried, and braised dishes; the roots are also used in traditional Asian herbal medicine. The petals, leaves, and rhizome can also all be eaten raw, but there is a risk of parasite transmission (e.g., Fasciolopsis buski): it is therefore recommended that they be cooked before eating.
Lotus rootlets are often pickled with rice vinegar, sugar, chili and/or garlic. It has a crunchy texture with sweet-tangy flavours. In Asian cuisine, it is popular with salad, prawns, sesame oil and/or coriander leaves. Lotus roots have been found to be rich in dietary fiber, vitamin C, potassium, thiamin, riboflavin, vitamin B6, phosphorus, copper, and manganese, while very low in saturated fat.
The stamens can be dried and made into a fragrant herbal tea called liánhuā cha (蓮花茶) in Chinese, or (particularly in Vietnam) used to impart a scent to tea leaves. This Vietnamese lotus tea is called trà sen, chè sen, or chè ướp sen. The lotus seeds or nuts (called liánzĭ, 蓮子; or xiān liánzĭ, 鲜莲子, in Chinese) are quite versatile, and can be eaten raw or dried and popped like popcorn, phool makhana. They can also be boiled until soft and made into a paste, or boiled with dried longans and rock sugar to make a tong sui (sweet soup). Combined with sugar, lotus seed paste becomes one of the most common ingredients used in pastries such as mooncakes, daifuku, and rice flour pudding.
In South Indian states, the lotus stem is sliced, marinated with salt to dry, and the dried slices are fried and used as a side dish. In Kerala (in Malayalam "താമര") and Tamil Nadu, this end product is called " Thamara Vathal". In Sri Lanka, finely sliced lotus rhizome cooked with coconut milk and spices is a popular curry known as Nelum Ala Vyanjanaya (නෙළුම් අල ව්යංජනය). In Vietnam, the bitter tasting germs of the lotus seeds are also made into a tisane (trà tim sen).
A unique fabric from the lotus plant fibers is produced only at Inle lake, Union of Myanmar and is used for weaving special robes for Buddha images called kya thingahn (lotus robe).
Nelumbo nucifera is the species of lotus sacred to both Hindus and Buddhists.
Hindus revere it with the divinities Vishnu and Lakshmi often portrayed on a pink lotus in iconography. In the representation of Vishnu as Padmanabha (Lotus navel), a lotus issues from his navel with Brahma on it. Goddess Sarasvati is portrayed on a white-colored lotus.
Often used as an example of divine beauty, Vishnu is often described as the "Lotus-Eyed One". Its unfolding petals suggest the expansion of the soul. The growth of its pure beauty from the mud of its origin holds a benign spiritual promise. In Hindu iconography, other deities, like Ganga and Ganesha are often depicted with lotus flowers as their seats.
The lotus plant is cited extensively within Puranic and Vedic literature, for example:
One who performs his duty without attachment, surrendering the results unto the Supreme Lord, is unaffected by sinful action, as the lotus is untouched by water.
In Chinese culture Confucian scholar Zhou Dunyi wrote:
I love the lotus because while growing from mud, it is unstained.
Many deities of Asian religions are depicted as seated on a lotus flower. In Buddhist symbolism, the lotus represents purity of the body, speech, and mind as if floating above the muddy waters of attachment and desire. According to legend, Gautama Buddha was born with the ability to walk with lotus flowers blooming everywhere he stepped. In Tibet, Padmasambhava, the Lotus-Born, is considered the Second Buddha, having brought Buddhism to that country by conquering or converting local deities. In Christianity, the St. Thomas Cross features a lotus underneath a cross.
In the classical written and oral literature of many Asian cultures the lotus is present in figurative form, representing elegance, beauty, perfection, purity and grace, being often used in poems and songs as an allegory for ideal feminine attributes. In Sanskrit the word lotus (padma पद्म) has many synonyms. Since the lotus thrives in water, ja (denoting birth) is added to synonyms of water to derive some synonyms for the lotus, like ambuja (ambu= water + ja=born of), neeraj (neera=water + ja= born of), pankaj, pankaja, kamal, kamala, kunala, aravind, arvind, nalin,nalini and saroja and names derived from the lotus, like padmavati (possessing lotuses) or padmini (full of lotuses). These names and derived versions are often used to name girls, and to a lesser extent boys, in India, Nepal and Sri Lanka, as well as in many other countries influenced by Indic culture, like Thailand, Cambodia, Indonesia and Laos.
Drawing in turn on these beliefs, the international Bahá'í community adopted this symbolism in the design of the Lotus Temple in New Delhi, India.
The flavonol miquelianin (Quercetin 3-O-glucuronide), as well as the alkaloids (+)-1(R)-coclaurine and (−)-1(S)-norcoclaurine, can be found in the leaves of N. nucifera. The plant also contains nuciferine and aporphine.