The definition of ‘berry’ gets picky

PUBLIC DOMAIN IMAGES Blackberry fruits and a blackberry flower. showing the tops of multiple ovaries in the flower’s center.

What’s in a name? That which we call a rose

by any other word would smell as sweet …

–Romeo and Juliet

Act II, Scene II

The suburban development outside Rochester, New York, was going up rapid fire, one cookie-cutter colonial after another. We were the fourth house down the hill from the K-4 elementary school on Oakview Drive, with nary an oak tree in sight.

PUBLIC DOMAIN IMAGES Blackberry fruits and a blackberry flower. showing the tops of multiple ovaries in the flower’s center.

Further down the street, past where the graders were extending the road, an open field dipped into a shallow, wooded ravine. Following the course of a boggy stream, the trees soon gave way to a brambly hillside. Blackberries!

One summer, my brother Rick and I convinced our mother to make a blackberry pie (to this day my favorite of all baked goods) from the copious pickings we would surely bring home in our outsized buckets. But sun-warmed blackberries on the cane are a great temptation and the intrepid foragers returned from the harvest with scarcely enough product for two smallish tarts.

Freshly picked blackberries, raspberries and strawberries — the stuff of a frigid mid-winter’s daydream. And it makes not a lick of difference that none of them is actually a berry.

That is to say, it makes a huge difference if you’re intrigued by questions about how things come to be the way they are, but not so much when the goal is raspberry shortcake or strawberry rhubarb pie.

Growing up, we all learned a vegetable’s a vegetable, a fruit’s a fruit and everyone understood the difference until fifth grade science, when Mrs. Hennesy mucked things up by explaining that the tomato is actually a fruit.

Even more painful, the tomato’s also a berry, as is the grape, banana, cucumber, chili pepper, orange, lemon, pumpkin and watermelon. But not most of the fruits that actually have the word “berry” as part of their name. OK, botanists allow that blueberries, cranberries and a few others are “true” berries, but yew berries — the small, red jobs (open at one end like a pitted olive) on the bushes in front of the house — aren’t fruits at all but highly modified evergreen cones.

So what’s a berry and why isn’t a blackberry considered one? For that matter, what’s a fruit? Well, of course, it all starts with sex.

There are two groups of seed-producing plants: conifers, which house their seeds in cones, and flowering plants that tuck them inside fruits. And a fruit, in short, is the outer part of the flowering plant’s ovary which expands and thickens after the eggs inside it have been fertilized.(Reproduction in mosses, ferns and a few other groups doesn’t involve seeds.)

This definition of fruit applies to everything from peaches and peppers to pea pods and peanuts, with the main difference being how thick and wet the ovary walls become.

Complexity No. 1: Within a flower’s ovary, the egg is housed inside a structure called an “ovule.” After its egg is fertilized, the ovule develops into a seed. In some species, the ovary holds a single ovule and therefore the finished fruit will have but one seed (think cherry or peach). In others, such as tomatoes or grapes (not the seedless types!), the flower’s ovary has numerous ovules, resulting in a fruit with multiple seeds.

Complexity No. 2: While the flower in many plants contains a single ovary, other species pack multiple ovaries into a given flower. For example, a blackberry flower has 50-100 or more tiny ovaries, each with the potential (if pollinated) to develop into a little fruit containing a seed. All those miniature fruits, or “drupelets,” glom onto each other, creating the unit we think of as “the” blackberry.

The closely related raspberry plays the game the same way, but strawberries put their own spin on things. The separate ovaries of a single strawberry flower never develop into juicy drupelets. Rather, the delicious red thing we eat is the enlarged base of the flower. And all those little brown things on the strawberry’s side are not seeds; they’re the dried up ovaries, each with a minute seed inside.

Citrus and squash flowers also have multiple ovaries but, unlike blackberries, they are fused together into a one unit so that you end up with a single fruit containing multiple seeds. (The separate segments of an orange represent the contributions of the different ovaries to the fruit.)

So then, what’s a berry?

Technically, it’s a berry if it (a.) contains multiple seeds developed from the ovary or ovaries of a single flower, (b.) is surrounded by a single skin or rind and (c.) is soft and squishy throughout.

Botanically speaking, blackberries, raspberries and strawberries, which don’t meet the “one-squishy-fruit-covers-all” criterion, are referred to as “aggregate” fruits.

Well, OK … but that which we call a berry, by any other word would taste as sweet.

Ken Baker is a scientist and a retired biology professor. If you have a natural history topic you’d like the author to consider for an upcoming column, email your idea to rweaver@advertiser-tribune.com.

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