The cashew tree is a tropical evergreen tree that produces the cashew seed and the cashew apple pseudofruit. The tree can grow as high as 14 m, but the dwarf cultivars, growing up to 6 m, prove more profitable, with earlier maturity and greater yields.
The cashew seed is commonly considered a Snack nut (cashew nut) eaten on its own, used in recipes, or processed into cashew cheese or cashew butter. Like the tree, the nut is often simply called cashew. Cashew allergies are triggered by the proteins found in tree nuts, and cooking often does not remove or change these proteins.
The Cashew is a flowering tree, native to northeastern Brazil, where it is called by its Portuguese name Caju
(the fruit) or Cajueiro
(the tree). It is now widely grown in tropical climates for its cashew "nuts" (and cashew apples. It is a small evergreen tree growing to 10-12 m tall, with a short, often irregularly-shaped trunk. The leaves are spirally arranged, leathery textured, elliptic to obovate, 4 to 22 cm long and 2 to 15 cm broad, with a smooth margin. The flowers are produced in a panicle or corymb up to 26 cm long, each flower small, pale green at first then turning reddish, with five slender, acute petals 7 to 15 mm long. What appears to be the fruit of the cashew tree is an oval or pear-shaped accessory fruit or false fruit that develops from the receptacle of the cashew flower. The true fruit of the cashew tree is a kidney or boxing-glove shaped drupe that grows at the end of the pseudofruit. Actually, the drupe develops first on the tree, and then the peduncle expands into the pseudofruit. Within the true fruit is a single seed, the cashew nut. Although a nut in the culinary sense, in the botanical sense the fruit of the cashew is a seed. However, the true fruit is classified as a nut by some botanists. The seed is surrounded by a double shell containing a caustic phenolic resin, urushiol, a potent skin irritant toxin also found in the related poison ivy. Some people are allergic to cashews, but cashews are a less frequent allergen than some other nuts.
As well as the nut and fruit, the plant has several other uses. In Cambodia, the bark gives a yellow dye, the timber is used in boat-making, and for house-boards, and the wood makes excellent charcoal. The shells yield a black oil used as a preservative and water-proofing agent in varnishes, cements, and as a lubricant or timber seal. Timber is used to manufacture furniture, boats, packing crates, and charcoal. Its juice turns black on exposure to air, providing an indelible ink.
Cashew is used for stomach and intestinal (gastrointestinal) ailments. Some people apply cashew directly to the skin as a skin stimulant and to seal (cauterize) ulcers, warts, and corns.