What is Monoecious?

Mary McMahon
Mary McMahon

Monoecious is a term which is used to describe an organism which has both male and female sex organs present, as separate structures. The term is most commonly used in reference to plants, although some animal species are monoecious as well, in which case it is more commonly referred to as hermaphroditism. There are a number of advantages to being monoecious, making it a fairly common sexual configuration, although it might seem a bit unusual to humans.

Plants that are monoecious produce male and female flowers.
Plants that are monoecious produce male and female flowers.

In a plant which has monoecious characteristics, the plant produces both male and female flowers. Alders and corn are two examples of plants which are considered monoecious. The male flowers on the plant are capable of fertilizing the female flowers, and they can also cross pollinate with other plants in the vicinity. The male and female flowers usually look different, as one is designed to create pollen for distribution, while the other develops ova which can be fertilized, resulting in the development of seeds.

Self fertilization is a useful ability, as it can ensure that a plant species survives and spreads when no other representatives of the species are present. For that reason, many monoecious plants can fertilize themselves, although they may have adaptations such as staggered blooming times which are designed to make it difficult, because self fertilization can weaken the genetics of the species. The ability to cross pollinate when it is an option can be extremely useful for the long term genetic robustness of the species.

In a consecutive monoecious plant, flowers of one sex appear first, followed by flowers of another sex. The plant can be either protogynous or protoandrous, depending on which sex appears first. Plants can also be simultaneously monoecious, meaning that male and female flowers appear at the same time. Plants typically evolve one approach or the other in response to the environments they develop in, as there are advantages and disadvantages to both, and sometimes humans deliberately breed plants to develop a specific desired sexual characteristic, such as the ability to produce male and female flowers simultaneously.

By contrast, dioecious plants are either male or female. For these plants, the presence of a plant of the opposite sex is necessary for fertilization to occur, although one male can fertilize many females. Plants can also have so-called “perfect” or “bisexual” flowers, in which both of the sexual organs are present in every single flower. These types of plants are known as hermaphrodites; hermaphroditism in plants should not be confused with the version seen in animals.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


How about those that are common to fiji (meaning usage in the forestry sector)?


Even if a species was able to synchronize its flowering times so that the male flowers came out first followed by the females, wouldn't that still cause a problem?

If the males are releasing pollen early, that is good, but even if the pollen makes it to another plant of the same species, the female flowers are still not present to receive the pollen.

Is there some way that the pollen can stick on the tree or something and wait for the female flowers to bloom?


@JimmyT and Emilski - I used to be easily confused by the prefixes until I figured out what they meant. Monoecious actually translates into "one house" which instantly clears things up, since both male and female flowers are on one plant. Obviously dioecious means "two houses" or separate plants.

In the case of an oak, they are monoecious, as are the majority of trees. Some dioecious trees are ashes and persimmons. As for pines, they are called gymnosperms don't make flowers. The trees can be either type, except instead of flowers, you have to refer to whether they produce male or female cones.

Perfect flowers are probably what you are most familiar with as being ornamental flowers like tulips or roses.


Does anyone know what the etymology of monoecious is? I was getting confused through the article, because it would seem to me that if something started with 'mono' that would mean it only had one of something. Instead, monoecious means it has both male and female flowers.

What would happen if a monoecious tree were the only one in an area, and it could only fertilize itself? The article mentions there could be genetic problems? Would it be the same type of situation as if two related humans had a child?


This was very interesting. I never realized there was so much variation in the types of flowers a plant could have.

The article talked about alders and corn being monoecious. What are some examples of the other plant types mentioned like dioecious plants and perfect flowers? What about common trees like oaks or pines?

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