The Nut That’s Just a Seed

Things are not always as they seem.  Take the popular cashew.  It looks for all the world like a nut, it is used culinarily as a nut, and just about everybody calls it a nut.  But it’s really a seed, and a strange one, at that.

The cashew tree, Anacardium occidentale, is an attractive, mid-sized tree with a broad canopy.  It produces large, leathery green leaves and yellowish-pink flowers.  Native to arid northeastern Brazil, it was discovered in 1578 by Portuguese colonists.  The first sighting by Europeans of the tree in fruit must have raised eyebrows, because what they beheld was a fleshy red or yellow structure with a seed hanging beneath it like a fat arboreal comma.  But the nut seemed to be useless for human consumption, as the poor colonists who ate it tended to end up a in a heap by the side of the road.  Consequently, the initial attraction of the tree was its colorful, fleshy, sweet-tasting receptacle, which looks like a fruit, but is really part of the fruit stalk.  It has come to be called Cashew Apple.  Known formally as an accessory fruit or pseudofruit, it grows on the seed and does not precede it.  Because the skin of the Cashew Apple is thin, it is not a good shipper.  In fact, the Portuguese settlers began the cashew’s pantropical distribution by sending seed from Brazil to their colonies in Mozambique and Goa to plant not for the ‘apple,’ but to control coastal erosion.

Through trial and error, the Europeans learned that the seed was edible if roasted so that the toxic shell could be cracked off.  Nevertheless, commercial trade in cashew ‘nuts’ didn’t start until the 1920s.  After ripe cashews fall from the tree, they are hand-collected and dried in the sun.  They are then roasted, after which they are shelled by machine or by hand.  In the nut trade, the leading cashew producers are widely separated — Viet Nam, Nigeria, India, Brazil and Indonesia.

Cashew trees are quite tolerant of drought; in fact, dry periods are required to stimulate flowering.  In southern Florida, they should be planted on well-drained sites and fed with a fertilizer for acid-loving trees.  You can find this very interesting species in 7-gal. containers at Richard Lyons’ Nursery.