Ottelia alismoides

Ottelia alismoides, commonly known as duck lettuce, is a species of aquatic plant native to Asia and northern Australia. Due to habitat loss and deterioration, it is endangered in China and Japan, although it is an invasive weed in America. Its genome has also been sequenced, resulting in a 6.45 Gb assembly to help study its unusual carbon metabolism mechanisms and aid in genetic conservation.

Description

A herb growing in fresh water. It develops tufts and keeps growing from year to year. The clumps are 60 cm wide. The leaves are very variable and have short or long leaf stalks according to the depth of water. The leaf blade of leaves which are under water are long and those which are floating are rounded. The leaves can be 1 m long and the blade 15-20 cm long by 15-20 cm wide. The base of the leaf is heart shaped. The leaves are green to bronze. They have prominent veins. The leafy bract around the flower has 5-10 wings. The flowers are 5-6 cm across and white with darker veins. They have 3 petals. The flowers are on the surface. The fruit are oblong and 2.5 to 4 cm long.

Edible Uses

The mature fruit are eaten raw or cooked; the leaves and leaf stalks are cooked or eaten raw with fish sauce or blanched; and the flower buds are used as a vegetable. The leaves, stalks, and flowers have an attractive flavour, and ripe fruit are especially eaten by children.

Traditional Uses

The mature fruit are eaten raw. They are also eaten cooked. The leaves and leaf stalks are eaten after cooking. They are also eaten raw with fish sauce. They are blanched. The flower buds are used as a vegetable.

Medicinal Uses

The leaves are antibacterial, febrifuge and rubefacient. The plant is used in the topical treatment of haemorrhoids, and is applied to the arms and legs as a poultice against fever. In clinical trials, an extract of the plant cured two cases of bilateral tuberculosis of the cervical lymph glands within 3 months. The results suggest that the plant is a promising medicinal herb with an anti-tubercular effect. A study isolated the compounds otteliones A and B from the plant. These compounds showed a remarkable in vitro cytotoxicity against various cancer cell lines.

Distribution

It is a tropical and subtropical plant. It can grow in stagnant water. It grows in wetlands. It occurs throughout the Philippines in shallow lakes and slow running streams. It needs bright light and warm water. In Yunnan. In Calicut Uni BG.

Where It Grows

Africa, Asia, Australia, Bangladesh, Cambodia, Central America, China, East Timor, Egypt, Europe, Guatemala, Himalayas, India, Indochina, Indonesia, Italy, Japan, Korea, Laos, Malaysia, Mediterranean, Myanmar, Nepal, North Africa, North America, Northeastern India, Pacific, Pakistan, Papua New Guinea, PNG, Philippines, SE Asia, Solomon Islands, Sri Lanka, Thailand, Timor-Leste, USA, Vietnam,

Cultivation

Plants can be grown from seed. They are planted on mud or in shallow, warm water. It can also be grown by removing suckers.

Other Uses

The plants are used to improve the water quality in ponds by capturing floating mud particles.

Production

In northeastern India plants flower and fruit from September to March.

Other Information

The leaves, stalks, and flowers have an attractive flavour. The ripe fruit are eaten especially by children. It is sold in local markets in China. It is cultivated.

Notes

There are about 21-40 Ottelia species. They grow in the tropics. There is one species in tropical America.

Synonyms

Also Known As

Chowehan, Dragon's tongue herb, Duck lettuce, Echeng, Kalabua, Keladi ayer, Khar, Mizu-obako, Panicola, Panikela, Panikola, Panikundri, Phak hob hep, Santawaa phak, Santawah pak, Senguntepa, Shui-che-chien, Shui jie cai, Shyamkola, Slab chrawa, Tarabang

References (50)

• Ambasta, S.P. (Ed.), 2000, The Useful Plants of India. CSIR India. p 417
• Anderson, E. F., 1993, Plants and people of the Golden Triangle. Dioscorides Press. p 217
• Baishya, S. Kr., et al, 2013, Survey of Wild Edible Fruits of Dhubri District, Assam, India. Plant Archives Vol 13 (1): 155-158
• BARC, 2016, State of Biodiversity for Food and Agriculture in Bangladesh. Bangladesh Agricultural Research Council.
• Baro, D., Baruah, S. and Borthukar, S. K. 2015, Documentation on wild vegetables of Baksa district, BTAD (Assam). Scholars Research Library. Archives of Applied Science Research, 2015, 7 (9):19-27

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