Colocasia is a genus of flowering plants in the family Araceae, native to southeastern Asia and the Indian subcontinent. Some species are widely cultivated and naturalized in other tropical and subtropical regions. Common names include tarul, karkala ko ganu, elephant-ear, taro, cocoyam, dasheen, aloochi paane, saru, hembu, chamadhumpa/chamagadda in Telugu, shavige gadde, and eddoe. Elephant-ear and cocoyam are also used for some other large-leaved genera in the Araceae, notably Xanthosoma and Caladium. The generic name is derived from the ancient Greek word kolokasion, which in the Greek botanist Dioscorides (1st century AD) meant the edible roots of both Colocasia esculenta and Nelumbo nucifera. It is thought that the edible roots of Colocasia esculenta have been cultivated in Asia for more than ten thousand years. The species Colocasia esculenta is an invasive species in wetlands along the American Gulf coast, where it threatens to displace native wetland plants.
|Range of the genus Colocasia.|
They are herbaceous perennial plants with a large corm on or just below the ground surface. The leaves are large to very large, 20–150 cm (7.9–59.1 in) long, with a sagittate shape. The elephant's-ear plant gets its name from the leaves, which are shaped like a large ear or shield. The plant reproduces mostly by means of rhizomes (tubers, corms), but it also produces "clusters of two to five fragrant inflorescenes in the leaf axils". Like other members of the family, the plant contains an irritant which causes intense discomfort to the lips, mouth and throat. This acridity is caused in part by microscopic needle-like raphides of calcium oxalate monohydrate and in part by another chemical, probably a protease. The acridity helps to naturally deter herbivores from eating it. It must be processed by cooking, soaking or fermenting – sometimes along with an acid (lime or tamarind) – before being eaten.
- Colocasia affinis Schott - Yunnan, Nepal, Assam, Bhutan, Bangladesh, Myanmar, eastern Himalayas
- Colocasia antiquorum, sometimes considered a synonym of C. esculenta.
- Colocasia esculenta (L.) Schott - taro, elephant-ear, eddoe - native to southern China, the Indian subcontinent, Indochina, Sumatra; naturalized in other parts of Asia as well as Africa, southern Europe, South America, Central America, the West Indies, the southeastern United States, and many oceanic islands including Hawaii
- Colocasia fallax Schott - Tibet, Yunnan, Himalayas, northern Indochina
- Colocasia fontanesii Schott - Yunnan, eastern Himalayas, northern Indochina
- Colocasia gigantea (Blume) Hook.f. – giant taro - southern China, Indochina, Malaysia, western Indonesia
- Colocasia lihengiae C.L.Long & K.M.Liu - Arunachal Pradesh, Yunnan
- Colocasia mannii Hook.f. - Assam, Nicobar Islands
- Colocasia menglaensis J.T.Yin, H.Li & Z.F.Xu - Yunnan, Laos, Myanmar, Thailand, Vietnam
- Colocasia oresbia A.Hay - Bangladesh, Sabah
- Colocasia tonoimo A.Hay - Unknown
- Formerly placed here
The plant can be grown in the ground or in large containers. They are grown outside year-round in subtropical and tropical areas. In temperate regions, they are planted out for the summer and dug up and stored over winter, dry and with ventilation to prevent fungal infection. They can be grown in almost any temperature zone as long as the summer is warm. Growth is best at temperatures between 20 to 30 °C (68 to 86 °F). The plants can be damaged if temperatures fall below 10 °C (50 °F) for more than a few days.
The root tuber is typically planted close to the surface. The first signs of growth will appear in 1 to 3 weeks. The adult plant will need a minimum of at least 1 m2 (11 sq ft) of space for good growth. They do best in compost-rich soil and in shade, but will grow reasonably well in average soil provided it is moisture-retentive. The plants should not be left to go dry for too long; if this does happen, the leaves will wilt; watering will allow the plant to recover if done before they get too dry. Periodic fertilisation (every 3 to 4 weeks) with a common plant fertiliser will increase yields.
The edible types are grown in the South Pacific and eaten like potatoes and known as taro, eddoe, chamadhumpa and dasheen. The leaves are often boiled with coconut milk to make a soup which is rich in iron.
In Cyprus, Colocasia has been in use since the time of the Roman Empire. Today it is known as kolokasi (Kολοκάσι). It is usually cooked with celery and pork or chicken, in a tomato sauce in casserole. "Baby" kolokasi is called "poulles": after being fried dry, red wine and coriander seed are added, and then it is served with freshly squeezed lemon. Lately, some restaurants have begun serving thin slices of kolokasi deep fried, calling them "kolokasi chips".
In the Indian subcontinentEdit
Both roots and leaves are eaten. In most of Northern India and Pakistan the root is called arvi or arbi. Common preparations include cooking with curry, frying, and boiling. In Mithalanchal (Bihar), the leaf is called airkanchan and is curried. In Rohtas, Bhojpur and Palamu (Jharkhand), it is known as kachchu.
In Gujarat, arvi leaves are used to make the dish patra. In Eastern part of Uttar Pradesh, arvi, known as aravi ka patta, is used to make the dish sahina. Arvi is also a very popular dish among the Hindu community in South Africa, where it is known as patha. In Manipur, the leaves are used in the Meitei ethnic cuisine, locally known as utti (pronounce ootti). The leaves are called paangkhoklaa by the Meiteis, while the edible corms are known as paan. Paan is often cooked with fermented soy beans to make curries. It is also used to make eromba, a Meitei side dish. In Odisha, the arvi the root is called saru. it is an important ingredient in dalma, a popular Odia dish.
In Shimoga, Uttara Kannada, Hassan, Chikkamagaluru, Dakshina Kannada, and the Udupi districts of Karnataka, arvi is used to make patrode. Additionally, in Shimoga, Chikkamagaluru & Hassan, the leaf is used to make a curry known as kesa or kesuvina palya. This curry is most often eaten with akki roti.
The Sindhi community call the root kachalu. They use it to make Sindhi curry and fry it with moong dal (green gram).
In Kerala, the leaves are used to make chembila curry, and the roots are used in chembu puzhukku, a traditional accompaniment to Kerala chembu. Various other recipes also exist locally. The stem and root are used in the preparation of stew and curry. In Kerala, chembu is planted in the month of May and can be harvested in December of the same year.
In Tamil Nadu, the roots are boiled, peeled, and/or fried and eaten as an accompaniment to rice. In Uttarakhand, the leaves are used to make a dish known as gaabaa, while the stem is enclosed in Urad dal paste and dried to make badi.
In Andhra cuisine, the roots are boiled, peeled, and fried as an entree with rice, or they may be boiled in a gravy with the leaves to make pulusu.
In Maharashtra, the leaves are called aloo and are used to make a sweet and sour curry with peanuts and cashew nuts that is commonly cooked during marriages. The leaf bases are mixed with curd to make the side dish dethi. The leaves are also coated in besan and fried to make the snack paatwadi or aloowadi.
In Gujarat, this leaf is called arvi (or alvi) and is used to make patra. This is a steamed dish similar to patrode, but with gram flour instead of the rice flour used in patrode. As in Maharashtra, the leaves are eaten as a fried snack.
In Nagaland, the leaves are dried, powdered, kneaded into a dough and baked into biscuits. These biscuits are burnt and dissolved in boiling water before being added into meat dishes to create a thick, flavourful dry gravy.
In Bengal, the plant is called kachu. Its leaves are used to wrap fish and prawns for steaming to make bhapa mach (steamed fish). The roots are used to make a thick creamy curry in which to cook prawns. The roots and stems are grated with coconut and used to create a chutney.
In the Levant, Colocasia has been in use since the time of the Byzantine Empire. The leaves are shown in mosaics from Israel as a platform, such as a plate or bowl, for serving of fruit to eat. For example, at the Kursi church mosaic.
Stem - Taro has much importance in ensuring food security, in earning foreign currency as being a cash crop and also as a means for rural development. Nutritionally, Taro contains more than twice the carbohydrate content of potatoes and yield 135 kcals per 100 g. Taro contains about 11% protein on a dry weight basis. This is more than yam, cassava or sweet potato. It contains 85-87% starch on dry matter basis with small granules size of 3-18 µm and other nutrients such as minerals, Vitamin C, thiamin, riboflavin and niacin better than other cereals. Leaves - Taro leaves, like higher plants, is rich in protein. The high protein content of the leaves favourably complements the high carbohydrate content of the tubers.  Colocasia leaves have demonstrated the ability of antidiabetic, antihypertensive, immunoprotective, neuroprotective, and anticarcinogenic activities. The detailed assessment of phytochemical compounds present in various extracts of the leaves shows the presence of active chemical compounds like anthraquinones, apigenin, catechins, cinnamic acid derivatives, vitexin, and isovitexin which are possibly responsible for the exhibited biological properties. Micronutrients, viz. iron (3.4–11.7 mg 100 g–1), copper (0.29–0.8 mg 100 g–1), magnesium (170–752 mg 100 g–1), potassium (0.4–2.4 g 100 g–1), and zinc (0.6–4.2 mg 100 g–1) are present in high amounts. 
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- World Book Encyclopedia
- Gupta, Kritika; Kumar, Ashwani; Tomer, Vidisha; Kumar, Vikas; Saini, Mona (2019). "Potential of Colocasia leaves in human nutrition: Review on nutritional and phytochemical properties". Journal of Food Biochemistry. 43 (7): e12878. doi:10.1111/jfbc.12878.
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