Euryale ferox, commonly known as prickly waterlily,[1] makhana, or Gorgon plant, is a species of water lily found in southern and eastern Asia, and the only extant member of the genus Euryale. The edible seeds, called fox nuts or makhana, are dried, and eaten predominantly in Asia.
Euryale ferox is a member of the water lily family Nymphaeaceae. The separate family Euryalaceae J.Agardh was proposed in 1858, a classification which has ultimately been rejected.[2] Unlike other water lilies, the pollen grains of Euryale have three nuclei.[3]
The genus is named after a mythical Greek Gorgon, Euryale.
The specific epithet ferox means fierce or ferocious.[4]
Euryale ferox is a perennial plant native to eastern Asia and southern Asia, and is found from northeast India to Korea and Japan, as well as parts of Pakistan and eastern Russia.
Recently, it has also been recorded in Serbia, Europe. It was likely dispersed to Serbia through migrating birds.[5]
Euryale ferox grows in fresh water ponds, producing flowers with white inner petals and violet outer petals. The leaves are large, round and peltate, often more than a meter (3 feet) across, with a leaf stalk attached in the centre of the lower surface. The leaves are deep green; the leaf veins are purplish. The stems and leaves are covered in sharp prickles. It can be grown in shallow water or rich soil. It does not tolerate shade or cold.[6]
Self pollination can occur in Euryale ferox. Pollen is known to be released prior to the opening of the flower.[7] The majority of Euryale ferox flowers are cleistogamous, not opening for cross-pollination, though some normally-opening (chasmogamous) flowers do occur.[8]
The chromosome count is n = 29. The genome size is 870.42 Mb.[9]
Fox nuts have traditionally been harvested by diving without breathing equipment to a depth of 8feet in freshwater ponds. This is arduous, with skin hazards from mud and the plant's thorns. In the 21st century, the National Research Centre for Makhana has pioneered the plant's cultivation in fields flooded to a depth of 1feet which makes production and harvesting easier. The area of land devoted to fox nut production has increased to 87000acres by 2022. The centre has developed a more productive variety, increasing farm income, and is designing a harvesting machine.[10]
The plant produces starchy white seeds that are edible. The plant is cultivated for its seeds in lowland ponds in India, China, and Japan. The Chinese have cultivated the plant for centuries.[11] More than 96,000 hectares of Bihar, India, were set aside for cultivation of Euryale in 1990–1991.[12] The Indian state of Bihar produces 90% of the world's fox nuts.[13]
In the northern and western parts of India, Euryale ferox seeds are often roasted or fried, which causes them to pop like popcorn.[14] These are then eaten, often with a sprinkling of oil and spices. They are also used in other types of cooking, especially to make a porridge or pudding called kheer.[15]
Evidence from archaeobotany indicates that Euryale ferox was a frequently collected wild food source during the Neolithic period in the Yangtze region, with large numbers of finds coming from the sites of Kuahuqiao, Hemudu, and Tianluoshan.[16] The earliest recorded use of E. ferox was found in Gesher Benot Ya'aqov, Israel, among artifacts of the Acheulean culture 750–790,000 years ago.[17]
The seeds are used in Cantonese soup.[18]
The seeds of foxnut are used in Ayurveda preparations and in traditional Chinese medicine.
It is classified on the Red List of endangered plants in Japan and given the designation "vulnerable".[19] It is classified as species of Least Concern (LC) by the IUCN Red List of Threatened Species. However, a population decline on the global scale has been reported. It is considered to be Endangered in South Korea.