If you enjoy doing crossword puzzles, you know that working through the clues often forces you to think outside the box. That’s because many words have multiple meanings, and puzzle clues aren’t always what they seem to be at first glance. For example, what’s a five-letter word for a peach? “Ah, that’s easy,” you say to yourself. “It’s a fruit.” Well yes, that’s true, but let’s pretend those letters don’t work with the surrounding clues. As you continue to fill in the puzzle, you eventually discover that the correct answer is the word drupe.
WHAT IS A DRUPE?
To help you understand drupes, let’s first take a quick look at the definition of fruit. Simply defined, a fruit is the fleshy or dry ripened ovary of a flowering plant that encloses a seed or seeds. Fundamentally, fruits are categorized based on their unique features, structures and seed types. A drupe is a botanical term that refers to just one specific category of fruit.
Fruits classified as drupes consist of three distinct parts: a thin skin or outer wall (exocarp), a fleshy edible part (mesocarp), and a hard, inedible central pit or stone (endocarp) that contains a single seed at maturity. When you consume a “stone fruit” such as a peach, apricot, plum, or nectarine, you’re eating a drupe. Lots of other fruits are drupes as well, such as olives, avocados, cherries, dates and mangos, to name just a few.
DOES A POME A DAY HELP KEEP THE DOCTOR AWAY?
Pomes constitute another important fruit category. Apples and pears are the most widely grown members of this family, which also includes crab apples, Asian pears, loquats, and quinces. Pome fruits are produced by flowering plants that belong to the apple subtribe (or Malinae) of the rose family (or Rosaceae). All pome fruits share a common structural similarity: They are comprised of fleshy tissue surrounding a fibrous, sometimes transparent membrane-like core. The core contains the seeds and separates them from the fleshy part of the fruit. Whereas a drupe has a single seed encased in a hard pit or stone, a pome contains several small seeds – typically five – encased within the membrane-like core.
Trees bearing pome fruits are favorite choices for planting in the home garden. The trees are deciduous and require a period of cold winter temperatures for the tree to break dormancy in spring. The fruits are typically harvested from late summer through late autumn and store well under controlled temperatures for an extended period. Members of the pome family have a high pectin content suitable for making the fruit into jams, jellies and preserves.
A number of fruit-bearing landscape plants such as serviceberry (Amelanchier species), red chokeberry (Aronia arbutifolia), and black chokeberry (A. melanocarpa) are also pomes. But if they are pomes, then you might be wondering why they have the word “berry” in their common names. The likely reason is because the fruits on these plants are berry-like in their appearance. And that leads us to the next category of fruits.
WHEN IS A BERRY NOT A BERRY?
To a lay person, a berry is a small, often colorful, usually juicy fruit. Strawberries, raspberries, and blackberries come to mind when most of us think of berries. But here’s a news flash for you. Botanically speaking, none of these are true berries. So, this begs the question: What exactly is a berry?
To a botanist, a berry is a simple fruit that is produced from the ovary of a single flower and has fleshy pulp and multiple seeds instead of a stone (like a drupe) or a core (like a pome). Blueberries, cranberries, currants, elderberries, gooseberries, and grapes fit this description and are true berries whereas strawberries, raspberries, and blackberries are perhaps more accurately described as “berry-like.”
THE DIFFERENCES BETWEEN TRUE BERRIES AND BERRY-LIKE FRUITS
When you delve a bit further into the botanical definition of a berry, you might find some surprises. For example, a tomato, which is one of our favorite vegetables, is technically a berry because the seeds are distributed throughout the fruit flesh rather than concentrated in a core in the center of the fruit. For that same reason, a banana is also technically a berry, although the seeds are very difficult to see.
Here are some other berry or berry-like categories to consider:
Hesperidia
A citrus fruit, such as an orange, lemon, lime, kumquat, or grapefruit, constitutes a specific kind of berry known botanically as a hesperidium. These fruits are characterized as having thick outer skins or rinds, very juicy interior flesh that is separated into segments, and seeds that are distributed throughout the flesh.
Pepos
Eggplants, tomatoes, tomatillos, and many other vegetables we buy in grocery stores or grow in our home gardens are technically berries. A special category of berry known botanically as a pepo refers to members of the cucurbit family of vegetables, which includes cucumbers, squashes and pumpkins. Specifically, Pepos are fleshy fruits characterized by a firm or hard outer skin or rind and no internal divisions.
Why aren’t pepos called fruits instead of vegetables? The answer lies in their taste. Although botanically they are fruits, most pepos have a savory rather than a sweet taste. Fruits are generally higher in sugar and calories than vegetables. Their sweeter taste profile is suitable for desserts and other dishes that benefit from a sweet component. Vegetables, on the other hand, offer a savory or herbaceous taste more suitable for main dishes and sides. The flavor profile of pepos tends toward this latter category, which is why we treat them as vegetables.
Here’s a generalized way to think about fruits and vegetables: If it contains seeds (like a tomato), then botanically it’s a fruit. If it doesn’t (like a carrot), then it’s a vegetable.
Aggregate or Compound Fruits
Some fruits that don’t fit the strict botanical definition of a berry may be categorized as aggregate or compound fruits. Whereas a true berry is produced from the ovary of a single flower, aggregate fruits are derived from a single flower that has more than one ovary. As they mature, the individual “fruitlets” join together to form a complete fruit. Raspberries and blackberries are examples of aggregate fruits.
Accessory fruits
An accessory fruit is derived from a part of a developing plant other than the ovary. A strawberry is a prime example. Although it is berry-like in color and taste, botanically it is a pseudocarp or “false fruit.” The edible part of the strawberry is not produced by the ovary of a flower. Rather, it is a multiple fruit consisting of many tiny individual fruits, called achenes, embedded in a fleshy receptacle. The non-fleshy seed-like achenes are the true fruits and are derived from an aggregate of ovaries. Each tiny achene surrounds an even tinier seed.
Figs, pineapples, and mulberries are other examples of accessory fruits that are made up of clusters of fruiting bodies.
DID YOU KNOW THAT NUTS ARE TECHNICALLY FRUITS?
So far, this article has described several categories of fleshy fruits. But fruit can also be derived from the dry ripened ovary of a flowering plant. This is where nuts enter the picture. Nuts can be broken down into two basic categories: true nuts and nut-like fruits. Both categories are referred to under the umbrella of “nuts,” but there are botanical differences between the two.
True nuts
Very simply, a true nut is a dry, single-seeded fruit (as opposed to a moist, fleshy fruit) that grows on a tree. The single seed is contained in a hard shelled pod that typically does not split to release the seed. A tool of some sort, such as a nutcracker or a hammer, is usually needed to crack open the hard shell to gain access to the edible seed. Chestnuts, hazelnuts, and acorns are examples of true nuts.
Nut-like fruits
Some of the foods we casually and collectively call “nuts” don’t meet the botanical definition of true nuts. For example, we think of peanuts as nuts because they have a similar nutritional profile to true nuts, plus they have the word “nut” in their name. Botanically, they are members of the legume family, which includes peas, beans, lentils, soybeans, and chickpeas. Peanuts form inside protective pods just like the other members of this family, but the pods grow underground and must be dug or pulled up out of the soil. Whereas true nuts do not split open on their own to reveal their seeds, the shells enclosing mature peanuts split open along two seams making the “nuts” readily accessible.
Other fruits that we think of as nuts are classified botanically as drupes rather than true nuts. Almonds, pecans, pistachios, macadamias and walnuts fall into this category. This can be confusing because we tend to envision drupes as fleshy, moist fruits such as peaches or plums. When we eat a peach, we eat the fleshy part and discard the hard pit containing the seed. The opposite is true when we eat an almond or a pistachio: We eat the seed inside the pit and discard the rest of the fruit because it is inedible. In either case, we are still eating a drupe. And just to confuse you further, these nut-like fruits can also be botanically classified as seeds.
SEEDS VERSUS NUTS
A seed is a mature fertilized ovule made up of three components: an embryonic plant, stored food reserves (endosperm), and a seed coat (protective covering). So, in addition to the almonds, pecans, pistachios, macadamias and walnuts mentioned above, cocoa beans and coffee beans are also seeds. When you think about it, many of our commonly used culinary spices such as allspice, black pepper, caraway, nutmeg, coriander, fenugreek, cumin, and mustard are seeds as well. And let’s not forget edible seeds including pumpkin (pepitos), chia, sesame, sunflower, poppy, pomegranate, and flax.
As for how seeds and nuts compare nutritionally, they are similar in terms of plant-based protein, levels of monounsaturated and polyunsaturated fats, vitamins such as vitamin E and minerals such as magnesium, potassium, and zinc. Although both nuts and seeds are good sources of dietary fiber, seeds tend to have a higher fiber content than nuts.
IN SUMMARY
Many of the fruits we eat can be classified into various categories based on their botanical characteristics and distinct features. But the distinctions are sometimes confusing. Here are a few key concepts to take away:
- Drupes have an outer fleshy part that surrounds a hard pit or stone with a seed inside. Example: Peach
- Pomes have a central core with a tough outer layer and five seeds typically. Example: Apple.
- Berries are fruits that form from a single ovary but have multiple seeds distributed throughout the fleshy pulp. Example: Blueberry
- True nuts grow on trees and contain both the fruit and the seed within a hard shell that does not open to release the seed. Example: Hazelnut.
- Legumes are dry fruits that split open along two seams when mature. Example: Peanut.
- Seeds are the mature, fertilized ovules containing an embryonic plant. Example: Almond.
AND FINALLY
Regardless of how we categorize these foods, it’s important to include them as part of a balanced and nutritious diet in accordance with recommended dietary guidelines. Both fruits and vegetables provide fiber, vitamins, antioxidants, minerals, and plant compounds essential to a healthy diet. See the United States Department of Agriculture’s Myplate website for in-depth information on dietary recommendations.
While plenty of fruit choices are available in grocery stores and farmer’s markets, it’s rewarding, economical, and educational to grow your own. If you are new to growing fruits, then the following Virginia Cooperative extension publications can help you get started: Small Fruit in the Home Garden, VCE Publication 426-840; Tree Fruit in the Home Garden, VCE Publication 426-841; and Native Nut and Fruit Trees and Shrubs of the Virginia Mountains and Piedmont, VCE Publication ANR-23NP.
SOURCES
Featured photo: Examples of several fruit types. Photo: Pat Chadwick
Berry, Hesperidium, Pepo, Master Gardeners of Northern Virginia
Cashews and almonds aren’t technically nuts. So what are they?, Office for Science and Society – McGill University
Drupe, Master Gardeners of Northern Virginia
Fruit, Pericarp, Endocarp, Exocarp, Mesocarp, Master Gardeners of Northern Virginia
Nut, Master Gardeners of Northern Virginia
Peanuts in the Garden, Utah State University
Pome, Master Gardeners of Northern Virginia
Quick-Start Guide to Nuts and Seeds, Harvard Health Publishing (Harvard Medical School)
The Strawberry: A Multiple Fruit, Carnegie Museums of Pittsburg