Dear Straight Dope:
Recently, I pointed out to someone the difference between fruits and vegetables. I then added that corn and nuts were neither of these because they were seeds, which make them grains. They swore up and down that corn was considered a vegetable. I learned that vegetables must be root, stem, or leave, and that fruit must be a fleshy covering of seeds. Corn does not fit either of these. So what's the real difference between fruits and vegetables (and grains, and so on, ad nauseum)? Settle it once and for all.
Matt, like you, I was taught simply that a vegetable is a root, stem or leaf, and that just about everything else is a fruit. I wasn’t really sure about the corn and nut thing, so after consulting several encyclopedias and my old botany textbook, I found the following definition, which all sources seem to basically agree upon:
A fruit is the matured ovary of a flower, containing the seed. After fertilization takes place and the embryo (plantlet) has begun to develop, the surrounding ovule becomes the fruit. Yum. I won’t go on about the four types of fruit–simple, aggregate, multiple and accessory–which explain things like berries and pineapples.
A vegetable is considered to be edible roots, tubers, stems, leaves, fruits, seeds, flower clusters, and other softer plant parts. In common usage, however, there is no exact distinction between a vegetable and a fruit. The usual example is the tomato, which is a fruit, but is eaten as a vegetable, as are cucumbers, peppers, melons, and squashes. The classification of plants as vegetables is largely determined by custom, culture, and usage.
Okay, now the part which may surprise you. A grain is described as the dry fruit of a cereal grass, such as the “seedlike fruits of the buckwheat and other plants, and the plants bearing such fruits.” So, grain is also a fruit.
Which brings us to the nut. Yes, you guessed it, a nut is, in botany, “a dry, one-seeded, usually oily fruit.” True nuts include the acorn, chestnut, and hazelnut. The term nut also refers to any seed or fruit with a hard, brittle covering around an edible kernel, like the peanut, which is really a legume. A legume is defined as “(the) name for any plant of the pulse family; more generally, any vegetable. Botanically, a legume–a pod that splits along two sides, with the seeds attached to one of the sutures–is the characteristic fruit of the pulse family.” Say what? A “pulse” is “the common name for Leguminosae or Fabaceae, a large family of herbs, shrubs, and trees, also called the pea, or legume, family. ” Please, make it stop!
So I guess we have learned today that just about everything is a fruit, unless of course, it’s a vegetable or a legume. Aren’t you glad you asked?
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