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Anacardium occidentale L. 1753
pronounced: an-uh-KAR-dee-um ock-sih-den-TAH-lee
(Anacardiaceae – the mango family)
common names: Cashew
Anacardium comes from two Greek words, ανα (ana), upwards, and καρδια (kardia), the heart, referring to the fact that the fruit looks a little like an upside-down heart. Occidentale is from the Latin occidentalis, of the west.
Cashew is derived from the Portuguese name for the tree, caju, which in turn derives from the indigenous Tupe name, acaju.
The tree pictured is in a garden in Wansfall Street, Picnic Bay.
The cashew tree is a native of Brazil, and the Portuguese took it to Goa, in India, between the years 1560 and 1565. From there it spread throughout south-east Asia, and eventually to Africa. Nuts were imported from India to the USA first in 1905.
This is a small evergreen tree to 10 – 12 m high, with a short, often irregularly-shaped trunk. The leaves are spirally arranged, leathery in texture, elliptic to obovate, 4 – 22 cm long by 2 – 15 cm broad, with a smooth margin. The flowers are produced in a panicle up to about 25 cm long, each flower small, pale green at first then turning reddish, with 5 slender, acute petals 7 – 15 mm long.
What appears to be the fruit of the cashew tree is an oval or pear-shaped accessory fruit (a pseudocarp or false fruit) that develops from the receptacle of the cashew flower. Called the ‘cashew apple’, it ripens into a yellow and/or red structure about 5 – 11 cm long. It is edible, and has a strong ‘sweet’ smell and a sweet taste. Its pulp is very juicy, but the skin is fragile, making it unsuitable for transport.
The true fruit is a kidney-shaped drupe that grows at the end of the accessory fruit. The drupe develops first, and then the peduncle expands into the cashew apple. Within the true fruit is a single seed, the cashew nut. This is a nut in the culinary sense, but botanically it is a seed. The seed is surrounded by a double shell containing an allergenic resin, anacardic acid, a potent skin irritant. The shell is removed before the nuts are sold to the public.
Sometimes the nut is harvested in its tender form, while the shell is still green in colour and has not hardened. At this stage the shell is soft and easily cut, but gloves should be worn as it is still corrosive. The kernel is then soaked in turmeric water to get rid of the corrosive material.
Many parts of the plant are used medicinally by the Patamona people of Guyana. The bark is scraped and either boiled or soaked overnight, and used as an anti-diarrhoeal. It also yields a gum used in varnishing. The seeds are ground into powders used as an anti-venom for snakebite. The nut oil is used as an anti-fungal, and for healing cracked heels.
The cashew nut is a popular snack, and its rich flavour means that it is often eaten on its own, lightly salted, or sugared. The nuts are also sold covered in chocolate. They are a staple in vegan diets, as they are an excellent source of protein. They factor in Thai and Chinese cuisine, usually in their whole form, and in Indian cuisine, where they are often ground into sauces, and also used as a garnish on desserts. In Malaysia, the young leaves of the tree are often eaten raw in salads. In Goa, the cashew apple is mashed to extract the juice, which is then fermented and doubly distilled to make a strong liquor called feni. Tanzanians make a similar liquor which they call gongo. In Mozambique, a strong home-brew, called agua ardente (burning water) is made from the cashew apple.
The timber (known as ‘white mahogany’ in Latin America) is fairly hard. The heartwood is basically brown with a golden or reddish cast, and the sapwood is distinct from the heartwood, being greyish white with a more-or-less pink tinge. It is used for light construction purposes, for firewood and charcoal. It also finds useful applications in the making of such items as wheel hubs, animal yokes, fishing boats, furniture and packing cases.
Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.
Photographs taken in Picnic Bay 2010, 2013
Page last updated 13th July 2018