Friday, March 23, 2012

Fun Fact Friday: Peanuts

The peanut is not a nut.

Okay, you've heard that before.  It's a legume.  But what is a legume?

In French légume refers to all vegetables, but English focuses more on specific simple, dry fruits.

Let's get Botanical!

Plants grow fruits so they can reproduce.  (Don't think of it as eating babies.  It's more like sex in your mouth.)  Legumes are a type of simple, dry fruit that typically go through dehiscence: the fruit splits in half to expel its seeds and reproduce.  A pea pod, for example, splits along its seam to release the peas inside.  Peanuts, however, are indehiscent.  The fruit must be eaten or decay in order for the seeds to be released.

Well, what's a nut?

To botanists, a true nut is "a simple dry fruit with one seed (rarely two) in which the ovary wall becomes very hard (stony or woody) at maturity, and where the seed remains attached or fused with the ovary wall."*  Examples of true nuts would be hazelnuts, chestnuts, and acorns.  The edible seed is attached to the shell.  Now, think back to the peanut.  Once you pop open that figure-eight pod, the seeds are free of the shell.  No prying required!

The peanut has more in common with the pea than the nut, making it a legume!

A (Very Brief) History of the Peanut

Peanuts, also called Groundnuts, are native to South America, but have been cultivated in China as early as the 17th century, most likely having been brought over by Portugese sailors.  Currently, the top three producers of peanuts in the world are China, India, and the US. (We're #3!  We're #3!)

The alternate name [groundnut] illustrates how the fruit grows.  The peanut's flowers grow in clusters on a pedicel.  Once these flowers self-pollinate and wilt, the pedicel elongates and digs itself into the ground, where the fruit develops.  The entire plant is removed for cultivation.

Arachis hypogaea: all of the peanuts, none of the allergies!

*From: Wikipedia
Photo Credit: Wikipedia
For more info check out Bill Casselman's site and the Peanut Wiki!

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