Cashew

The cashew (Anacardium occidentale; syn. Anacardium curatellifolium A.St.-Hil.) is a tree in the flowering plant family Anacardiaceae. The cashew grows on a medium sized tree that is native to the rainforests of South America. Cashew trees were exported to other regions and are now grown in many tropical areas of the world.

The tree produces red flowers and soon after, the cashew tree produces yellow, orange, or red fruit commonly known as the cashew apple. Although most people in the United States are not familiar with this fruit, the cashew apple is eaten by many people of the world. Some people make juice or wine from this fruit. The cashew apple contains a lot of antioxidants, including vitamin C.

The part of the cashew tree that interests most people in the United States are the nuts that grow on the bottom of the red fruit. This part is the shell that contains the cashew nut.

Unlike other nuts you find at the grocery store, you never see cashew nuts still in the shell. This is because the cashew shell contains oil that is very irritating to the skin and mucous membranes.

Description

Anacardiaceae occidentale is native to tropical Central and South America, notably 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, including parts of Africa and Asia, for its cashew "nuts" and "cashew apples".

The cashew is a small evergreen tree (or shrub) growing to ten-12 meters tall, with a short, often irregularly-shaped trunk. The leaves are spirally arranged, leathery textured, elliptic to obovate, four to 22 centimeters long, and two to 15 centimeters broad, with a smooth margin. The flowers are produced in a panicle or corymb up to 26 centimeters long. Each flower is small, pale green at first, then turning reddish, with five slender, acute petals seven to 15 millimeters 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. Called the cashew apple (better known in Central America as "marañón"), it ripens into a yellow and/or red structure about five–11 centimeters long. In botany, a fruit is the ripened ovary—together with seeds—of a flowering plant. The term false fruit (pseudocarp, accessory fruit) is sometimes applied to a plant structure that resembles a fruit, but is not derived from a flower or flowers.

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 called a nut in the culinary sense, in the botanical sense, the fruit of the cashew is a seed. The true fruit, however, 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 in the sumac family. Some people are allergic to cashews, but cashews are a less frequent allergen than some other nuts.