As the daylight hours lengthen and the first signs of spring abound, farmers markets are popping up from coast to coast. With so many tasty edibles ranging from fresh produce to baked goods, it’s no wonder people flock to their local farmers market to spend the afternoon strolling among the displays. It can be easy to set out for a few veggies and to come back with a basket full of impulsive finds. Even if you stick rigidly to your shopping list, you may be surprised to learn that the fruits and vegetables you brought home with you are not exactly what you thought they were. When we call certain foods a fruit or a vegetable, botanists often disagree. What’s really in your basket?

Figure 1 ~ Some commonly confused produce

It all starts with a flower

Flowers are the reproductive structures of angiosperms, more commonly known as flowering plants, and can display a vast array of shapes, sizes, and colors. The basic anatomy of a flower consists of four layers supported by the receptacle, a thickened portion of the stem at the base of the flower. The outer two layers are made up of sepals and petals. The inner two layers are the androecium and the gynoecium, the male and female parts of the flower, respectively. The androecium contains the stamen, consisting of a filament and sperm-producing anther. The gynoecium contains the pistil, a tube leading down to the ovary, a chamber that contains the ovules.

The function of a flower is to house the reproductive cells of the plant, the eggs and pollen, and ultimately, to produce a seed which will grow into the next generation. Initially, the pollen moves from the male anther to the female pistil in a process called pollination. Next, the pollen grain generates a tube that extends down the pistil into the ovary chamber and deposits the sperm near the egg. Finally, when the sperm and egg cell fuse together in a process called fertilization, it triggers the development from a flower into a fruit. The fruit develops from the ripening and thickening of the walls of the flower’s ovary, and the seeds develop from the ovules within the ovary. This same basic process occurring in different plants gives rise to the diversity of fruit types that are available to purchase at a nearby farmers market.

Figure 2 ~ Components of a flower

What am I really eating? 

It turns out that our definitions of common fruits and vegetables are technically not correct. The botanical definition of a fruit is a ripened ovary of a flower with any attached accessory structures, whereas a vegetable is the vegetative portion of the plant consisting of the roots, stems, or leaves. This categorizes things like strawberries, apples, and grapes as fruits, and celery, broccoli, and cabbage as vegetables. However, from a botanist’s perspective, certain fruits are often mistaken for vegetables.

Take a tomato for example. Have you ever had tomato pie or ice cream with tomatoes on top? Probably not, but botanists unanimously agree that a tomato is a fruit. Recall the botanical definition: a fruit is the ripened ovary of a flower. A tomato develops from the ovary wall of a flower and each seed inside the tomato was once an ovule. String beans, avocados, eggplants, squash, pumpkin, cucumbers, peppers, and corn also fulfill the requirements for being a fruit. However, what should be called a fruit has long been contested and botanists will undoubtedly not convince everyone that a tomato is a fruit. In fact, the U.S. Supreme Court ruled that tomatoes were vegetables in 1893 [1].

Things get even more interesting when we take a closer look at fruit types [2].  Fruits can either be simple, developing from a single ovary of one flower, or compound, developing from several ovaries of one or more flowers. A peach is an example of a simple fruit. There are two types of compound fruit: multiple and aggregate. A multiple fruit develops when several flowers, each with their own single ovary, fuse. An example is a pineapple, where each wedge is the product of a single ovary from a single flower. In comparison, an aggregate fruit develops when multiple ovaries on a single flower merge. A raspberry is an aggregate fruit, where the rounded lobes are derived from multiple ovaries on a single flower.

The strawberry is an interesting case that exhibits the diversity of fruit development.  In the case of the strawberry, each small, black seed is actually a fruit and the red, sweet juicy portion is an enlarged receptacle. In this way, a strawberry is also an accessory fruit, meaning that an accessory part of the flower forms the fleshy fruit in addition to the ovary. To add to this perplexing situation, botanists define a berry as a fleshy fruit produced from a single ovary that often contains more than one seed. As an accessory fruit, a strawberry is not a berry! However; the aforementioned tomato is, along with grapes, bell peppers, and bananas.

Bigger issues

On top of the items in your basket not being what you thought they were, there may be bigger concerns at hand when it comes to future farmers market shopping trips. The complex biology of fruits and vegetables can make them difficult to grow and vulnerable to extreme weather events. As California faces a prolonged drought, and its worst one on record, the United State’s top agricultural producer is being deprived of the water it needs to produce everything from beef to produce. Similar extreme weather episodes around the world are threatening global food production and increasing food prices [3]. So whether you set out for fruits or vegetables this spring, take a moment to appreciate the triumphs of biology on display at your local farmers market.

Morgan Furze is a PhD student in the Organismic and Evolutionary Biology Program. 


1. When The Supreme Court Decided Tomatoes Were Vegetables,

2. Colorado State University Extension’s Plant Structures: Fruit, Key to Common Fruit Types,

3. California Farms Going Thirsty as Drought Burns $5 Billion Hole.

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