Flowers

The flowers are the sexual parts of a plant.

The have evolved to release pollen, (and receive it from other plants.)

The huge diversity of the flowering plants is reflected in their diverse combinations of sexual arrangements.

what are the different parts of flower called

and what do they do?

The flower itself is made up many different parts with many different names. The parts may vary considerably in shape and look, and it can be confusing recognizing the different parts of a flower. However, these variations in shape and number of features has traditionally been the main way to identify species, and thus to classify and determine species relationships.

The largest, best known, most obvious and commonly recognized part of the flower is usually the collection of features and structures that make up the perianth:

This consists of the lowest layer called the corona/calyx (which is made up of the sepals), and the next layer up, the corolla (which is made up of the petals). These are non-sexual or non-reproductive parts of a flower, and are mostly used as visual aids to attract pollinators. The numbers and look of the sepals vary, but they are mostly just greenish. However, the petals of a flower are usually more colourful, (such as the pretty pink petals of the melastomid flower pictured below)and can vary from thin and pen shaped, to elaborate and luscious (as in the orchids).

The sexual parts of the flowers are also well known, but are bit more confusing. The male parts of the flower are known as the androecium and made up of the usually pencil-shaped stamens (these are normally long and stick out of the flower, so it is easy to remember that they are the ‘boy’ bits). There are frequently many stamens, and they located just inside the petals. The stamen itself is made up of the stick-like filament and the anthers at the end. The anthers contain the pollen grains. When the pollen mature, the anther will split and be ready to release the pollen. Pollen may be light and wind dispersed, or it may be collected by an animal. The pollen grains produce two male sperm cells (and remember that when you next get pollen on your face or up your nose!).

The female part of the plant is called the gynoecium (this means ‘female house’) and is made up of the usually squatter, slightly pear shaped carpel (think of the traditional Venus female shape). This is usually located in the centre of the flower. The ovary is inside this structure, the style is the part sticking up, and the stigma is the end. In the Thespesia pictured below, the carpel is the main central structure, with many reduced yellow stamens hanging off it.

There are so many variations with all the different combinations of different flower parts. For example, the stamens may be in huge numbers and be colourful and large. These effectively act like colourful petals to attract animals for pollination, as in many species in the Myrtaceae and Barringtonia.

what do flowers do?

The main job of flowers is to release pollen. This can be done in various ways, such as through wind or water, but the most obvious way is by using animals to do the work.

That is why we humans find flowers so attractive; they have evolved to be attractive to animals. That beautiful smell of a gardenia is designed to peak at night and attract moths. The bright red of a hibiscus is to attract birds. The taste of nectar of paperbarks is to attract lorikeets and flying fox.

where can I find flowers?

Flowers are found in most ecosystems, even underwater with sea grasses.

In Australia, I think they are at their most spectacular and accessible in temperate and tropical woodlands, grasslands and wetlands, where the flowers have evolved quite large to attract honeyeaters,and many of the smaller insect attracting flowers are low down and easy to see.

But most people tend to think of the most spectacular flowers being found in the tropical rainforest.

Rainforest flowers; what makes them different?

Where can I see tropical rainforest flowers?

This information contains edited extracts from the book: