What is an actinomorphic and a zygomorphic flower?

Flowers can be classified in many ways: according to color, size, botanical genus to which the plant that produced them belongs,… and also on how their petals are distributed. In this sense, they can be zygomorphic or actinomorphic.

If you want to know what the characteristics of each type are and some examples of plants that produce them, then you will be able to find out .

What are the characteristics of actinomorphic and zygomorphic flowers?


The actinomorphic flower is one that has radial symmetry ; that is, they can be divided into 3 or more identical sections related to each other. Also, it may or may not be divided into two symmetrical halves.

To make it easier to understand, you will know if it is actinomorphic if, when you cut it in half, you have two exactly the same halves. This will not be the case if it is zygomorphic, as one of those parts will always be larger than the other.


As we mentioned, the vast majority of plants have this type of flowers, but there are exceptions: most of the subfamilies of the Fabaceae family, except for Mimosoideae and Caesalpinioideae, some scrofulariaceae and orchids have zygomorphs. Here are some of the actinomorphic flowering plants:

Bougainvillea ( Bougainvillea spectabilis )

Image – Wikimedia/ Lalithamba from India

It is an evergreen or deciduous shrub depending on the climate native to Brazil. It is a very beautiful and easy-to-care plant, which has become popular in the hot climate regions of the planet.

Related article:Bougainvillea spectabilis

Geranium of the roads ( Geranium molle )

Image – Wikimedia/ Aiwok

It is an annual plant with pubescent stems and leaves, native to Europe except Iceland. It can be found relatively easily in wastelands, dunes, and in mowing meadows.

Flamboyan ( Delonix regia )

It is a deciduous, semi-evergreen or evergreen tree, depending on the climate, native to Madagascar. It has a very high ornamental value, which is why it is grown in the tropical and subtropical gardens of the world.

Related article:Flamboyan

Tea plant ( Camellia sinensis )

It is a shrub or evergreen tree native to southern China, very popular for its leaves, since tea is made with them. However, its flowers are also noteworthy: they measure about 4 centimeters, and are very beautiful yellowish-white.

Related article:Camellia sinensis


A zygomorphic flower is one that has a bilateral plane of symmetry, or what is the same: when dividing it in half, there will always be two different halves, either in size, in number of petals and/ or sepals or bracts, … Or all at once.


Some examples are plants in the Faboideae subfamily, such as the following:

Pea ( Pisum sativum )

Image – Wikimedia/ Dyorkey

It is an annual cycle herb with a more or less climbing habit native to the Mediterranean basin. It is widely cultivated for its seeds, also called peas or peas, with which various dishes are prepared.

Related article:Potted pea cultivation

Alfalfa ( Medicago sativa )

Image – Flickr/ Peter O’Connor

It is a perennial herb with erect and pubescent stems native to Persia widely cultivated and used throughout the world as grass.

Related article:Cultivation of alfalfa

Beans ( Phaseolus vulgaris )

Image – Flickr/ Thomas Bresson

It is an annual herb that grows upright or as a climber native to Mesoamerica. It produces fruits with about ten seeds each, which are called beans, kidney beans or beans. These are edible.

Related article:Beans (Phaseolus vulgaris)

Broad beans ( Vicia faba )

Image – Flickr/ Salomé Bielsa

It is an annual cycle herb native to the Mediterranean region or Central Asia (not yet clear), with an upright habit. It is grown for its seeds, which are suitable for human consumption.

Related article:Broad bean cultivation guide

What are flowers and what are they for?

Flowers are very important parts for angiosperms. Thanks to them, they can create new generations, and therefore, keep a species alive for a long time (thousands, maybe millions of years).

So, despite the fact that today they can cause allergies in some people (including myself) the nostrils are not their target: but the stigmata of other flowers.

It is believed that they appeared about 140 million years ago, in the early Cretaceous period, at low latitudes. However, it was not until about 65-75 million years ago that they actually managed to conquer all the biomes on planet Earth except the polar regions.

Most of them are very brightly colored, and this is so for a reason: in nature there are several candidate animals for pollinators and many plants. For this reason, flowers must do everything possible to attract at least some of them, since the competition in some places can be very high.

Image – Flickr/ jacinta lluch valero

But there are also others that go unnoticed, such as the Aspidistra for example. His are so small that, when they sprout between the stems, they are hardly visible. Why is this happening?

Well, if you ever see or acquire a plant that apparently never blooms, you should ask yourself first if it is an angiosperm or if on the contrary it is a gymnosperm: if it is one of the first, then you can be sure that at some point in its evolution ‘hired’ the services of an insect or animal that is either not able to distinguish colors, has no smell, and/ or is nocturnal. Then you can look for flowers -or remains of flower buds- small, colors that go unnoticed -such as green- and/ or without aroma.

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