I love fruit! It’s one of the few things you can eat that is both sweet and good for you! There is also such a wide variety, from apples to grapes, watermelons to kiwis, and pineapples to pomegranates. We know these are all fruits, and
we can think of a great many more—too many in fact to name—all different in
taste, texture, and form. How can they be so different, yet all be called fruits? What exactly is a fruit?
A fruit is the part of a flowering plant which develops from the ovary of the flower, and usually either consists of or carries the seeds of the plant (bananas are one common exception—they are actually a seedless berry!). Therefore, in the strictest botanical sense, not only are all of our previous examples fruits, but so are tomatoes, corn kernels, wheat grains, peas, and almost all nuts. This is because all of these are or contain seeds, and have developed from the ovary of a flower.
we can think of a great many more—too many in fact to name—all different in
taste, texture, and form. How can they be so different, yet all be called fruits? What exactly is a fruit?
A fruit is the part of a flowering plant which develops from the ovary of the flower, and usually either consists of or carries the seeds of the plant (bananas are one common exception—they are actually a seedless berry!). Therefore, in the strictest botanical sense, not only are all of our previous examples fruits, but so are tomatoes, corn kernels, wheat grains, peas, and almost all nuts. This is because all of these are or contain seeds, and have developed from the ovary of a flower.
There are many different ways to classify a fruit, and over 15 different common fruit types (for more information, please visit the Colorado State University Extension website by clicking here). However, in general, there are really three basic types:
1. Simple fruits: These form from one flower with only one ovary. Peaches are an example of a simple fruit.
2. Aggregate fruits: These form from one flower with many ovaries. Raspberries are an example of an aggregate fruit.
3. Multiple fruits: These form from the fusion of many flowers which grow on one structure.
The ovaries of these flowers fuse to form one fruit. Examples include pineapples and figs.
Unfortunately, it isn’t always easy to tell the difference between these different types just by looking at the mature fruit. For example, if you have ever cut open a pomegranate and seen all the loose seeds inside, each surrounded by a small, separate piece of red flesh, and clinging to a single leathery husk, you might think this is an aggregate fruit. In fact the pomegranate is a simple fruit (a berry) from one flower with one ovary, but still producing many seeds. In order to really understand what sort of fruit you are looking at, you really need to take a good look at the flower.
Let’s take a look at a picture of the inside of a flower.
1. Simple fruits: These form from one flower with only one ovary. Peaches are an example of a simple fruit.
2. Aggregate fruits: These form from one flower with many ovaries. Raspberries are an example of an aggregate fruit.
3. Multiple fruits: These form from the fusion of many flowers which grow on one structure.
The ovaries of these flowers fuse to form one fruit. Examples include pineapples and figs.
Unfortunately, it isn’t always easy to tell the difference between these different types just by looking at the mature fruit. For example, if you have ever cut open a pomegranate and seen all the loose seeds inside, each surrounded by a small, separate piece of red flesh, and clinging to a single leathery husk, you might think this is an aggregate fruit. In fact the pomegranate is a simple fruit (a berry) from one flower with one ovary, but still producing many seeds. In order to really understand what sort of fruit you are looking at, you really need to take a good look at the flower.
Let’s take a look at a picture of the inside of a flower.
This picture shows us all the reproductive organs of the flower; let’s focus on the ovary, which is zoomed in on the left side. Note this flower has only one ovary, and so if it produces fruit that fruit will be considered a simple fruit. However, notice also that this flower has more than one “ovule” or egg cell, and it is these structures which become the seeds of the fruit. So this flower will produce a simple fruit having many seeds, much like the pomegranate. Now take a look at the pomegranate flower, and it becomes clear why this is considered a simple fruit.
For an aggregate fruit, let’s take a look at a picture of a raspberry flower:
This flower has multiple ovaries, and each ovary has one ovule. So the raspberry will be an aggregate fruit, and each of the ovaries will develop a single seed.
For a multiple fruit like the pineapple, let’s look at a picture of a pineapple flower, and the fruit that develops:
For a multiple fruit like the pineapple, let’s look at a picture of a pineapple flower, and the fruit that develops:
The large pineapple flower is actually a group of many flowers, each of which will become one section of the mature pineapple fruit*.
TRY IT!
Now that you understand how the flower becomes the mature fruit, and how this influences the type of fruit formed, try identifying the following pictures of flowers as forming simple, aggregate, or multiple fruits. If the fruit is a simple fruit, will it have one or many seeds? Be sure to write down your answers!
1) Peach
TRY IT!
Now that you understand how the flower becomes the mature fruit, and how this influences the type of fruit formed, try identifying the following pictures of flowers as forming simple, aggregate, or multiple fruits. If the fruit is a simple fruit, will it have one or many seeds? Be sure to write down your answers!
1) Peach
2) Blueberry
3) Apple
4) Fig
5) Strawberry
When you've written down all your answers, scroll down.
Answers:
1) Peach: Simple fruit, one seed
2) Blueberry: Simple fruit, many seeds
3) Apple: Simple fruit, more than one seed
4) Fig: Multiple fruit
5) Strawberry: Simple fruit, many seeds
For more pictures of flowers that become fruit, please see this website from the University of California Davis http://fruitandnuteducation.ucdavis.edu/generaltopics/AnatomyPollination/Anatomy_Tree_Fruit_Nut_Crops/
*The picture of a pineapple flower found on Wikipedia is used with permission, shared under the Creative Commons Attribution-Share Alike 3.0 Unported License. A link to that license appears here: http://creativecommons.org/licenses/by-sa/3.0/legalcode
Answers:
1) Peach: Simple fruit, one seed
2) Blueberry: Simple fruit, many seeds
3) Apple: Simple fruit, more than one seed
4) Fig: Multiple fruit
5) Strawberry: Simple fruit, many seeds
For more pictures of flowers that become fruit, please see this website from the University of California Davis http://fruitandnuteducation.ucdavis.edu/generaltopics/AnatomyPollination/Anatomy_Tree_Fruit_Nut_Crops/
*The picture of a pineapple flower found on Wikipedia is used with permission, shared under the Creative Commons Attribution-Share Alike 3.0 Unported License. A link to that license appears here: http://creativecommons.org/licenses/by-sa/3.0/legalcode
