Euryale ferox

''Euryale ferox'', commonly known as prickly waterlily, 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.

The plant is cultivated for its seeds in lowland ponds in India, China, and Japan. The Indian state of Bihar produces 90% of the world's fox nuts. The Chinese have cultivated the plant for centuries. In India, more than 96,000 hectares of Bihar were set aside for cultivation of ''Euryale'' in 1990–1991. In the northern and western parts of India, the seeds are often roasted or fried, which causes them to pop like popcorn.

Description

''Euryale ferox'' grows in freshwater ponds. The leaves are large, round and peltate, often more than across, sometimes to diameter, with a highly distinctive puckered surface; the leaf stalk is 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. The flowers are 5 cm diameter, with violet outer petals and white inner petals; they often pierce through the leaves. The fruit is a spiny capsule 5–10 cm diameter, containing numerous spongy-textured seeds. It grows in rich soil under shallow or deeper water. It does not tolerate shade or cold when growing, though when dormant in winter it is not harmed by severe winter cold.

File:Euryale ferox Salisb. foliage.jpg, Unfurling leaf of ''Euryale ferox'' at Kanjia Lake, Odisha, India
File:Kazo Habitat Euryale Ferox 1.JPG, A pond of cultivated ''Euryale'' in Japan
File:E-ferox-20021002a.jpg, Fruit
File:Cascada del cocodrilo. La Mortella. 02.JPG, Cultivated as an ornamental plant in Italy
File:Euryale ferox Salisb. seedling.jpg, ''Euryale ferox'' seedling (herbarium specimen)
File:Euryale ferox grains (1).jpg, Harvested seeds

Reproduction and genomics

Self pollination can occur. Pollen is released before the flower opens.Povilus, R. A., Losada, J. M., & Friedman, W. E. (2015)
"Floral biology and ovule and seed ontogeny of ''Nymphaea thermarum'', a water lily at the brink of extinction with potential as a model system for basal angiosperms."
Annals of Botany, 115(2), 211-226. The majority of ''Euryale ferox'' flowers are cleistogamous, not opening for cross-pollination, though some normally-opening ( chasmogamous) flowers do occur.

The chromosome count is n = 29. The genome size is 870.42 Mb. The chloroplast genome is 159930 bp long.

Cultivation

The seeds and petioles are used as food. The plant is cultivated for its seeds in lowland ponds in India, China, and Japan. The Chinese have cultivated the plant for centuries. In India, more than 96,000 hectares of Bihar, where it is called Mithila Makhana, were set aside for cultivation of ''Euryale'' in 1990–1991. Bihar produces 90% of the world's fox nuts. In the northern and western parts of India, ''Euryale ferox'' seeds are often roasted or fried, which causes them to pop like popcorn. 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. The seeds are used in Cantonese soup, in Ayurveda preparations, and in traditional Chinese medicine.

Evidence from archaeobotany indicates that ''Euryale ferox'' was a frequently collected wild food source during the Neolithic period in the Yangtze region, with many finds from the sites of Kuahuqiao, Hemudu, and Tianluoshan. The earliest recorded use of ''E. ferox'' is from Gesher Benot Ya'aqov, Israel, among artifacts of the Acheulean culture 750–790,000 years ago.

Fox nuts have traditionally been harvested by diving without breathing equipment to a depth of 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 which makes production and harvesting easier. The area of land devoted to fox nut production has increased to by 2022. The centre has developed a more productive variety, increasing farm income, and is designing a harvesting machine.

Taxonomy

The species was described by Richard Anthony Salisbury in 1805. It is a member of the water lily family Nymphaeaceae. It is the type species of its genus. The placement in a separate family Euryalaceae J.Agardh, which was proposed by Jacob Georg Agardh in 1858, has been rejected. Unlike other water lilies, the pollen grains of ''Euryale'' have three nuclei.

The genus is named after a mythical Greek Gorgon, Euryale. The specific epithet ''ferox'' means fierce or ferocious in Latin.

Distribution

''Euryale ferox'' is a perennial plant native to a range from northern India to Taiwan and through China, Korea, and Japan to far eastern Russia.

India is the largest global producer of Makhana (fox nut), with over 90% of cultivation concentrated in the floodplain regions of Bihar, particularly in districts like Darbhanga, Madhubani, and Purnia. Makhana has also emerged as a key agri-export commodity, valued for its nutritional profile and GI-tagged identity.

In 2022, ''E. ferox'' was recorded as naturalised in Serbia, probably dispersed from plants grown in botanical gardens by migrating birds. The iNaturalist website also records an observation of a naturalised plant in 2024 in Minnesota, USA, with the note that it was removed by the Minnesota Department of Natural Resources to prevent its spread.

Conservation status

The species is classified on the Red List of endangered plants in Japan and given the designation "vulnerable". 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 classified as vulnerable (VU) in South Korea.

See also

* Water chestnut – other aquatic plants with edible nuts

Notes

References

Further reading

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External links

''Euryale ferox'': Images & occurrence data
from GBIF
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{{Taxonbar, from=Q310795

Flora of Korea
Flora of China
Flora of Bangladesh
Flora of India
Flora of Mongolia
Flora of Japan
Flora of Myanmar
Flora of Taiwan
Flora of Russia
Medicinal plants of Asia
ferox
Plants described in 1805
Plants used in traditional Chinese medicine
Taxa named by Richard Anthony Salisbury