Australian "Pea" Flowers

The "pea" family of plants is a large group of over 500 genera and over 12,000 species which occurs throughout the world and which consists of herbs, shrubs, trees and climbing plants. Some exotics, such as the edible peas and beans, clover, lucerne and sweet peas are well established as commercial or ornamental crops while others, such as English broom (Cytisus scoparius) and gorse (Ulex europaeus), have long since outlived their welcome in some areas and become environmental weeds.

The pea-flowered plants are legumes and are able to take-up ("fix") their nutrient requirements for nitrogen directly from the atmosphere with the aid of soil bacteria (Rhizobium spp.). This occurs in nodules on the roots of the plants. The pea flowers are not the only plants capable of this - the wattles (Acacia sp.) and the sennas (Senna sp.) and their relatives are also legumes.

In Australia, there are about 140 genera and 1,100 species of pea plants. They are found in every state and territory of Australia, from coastal cliffs to alpine areas, from the tropics to the arid inland. Many of Australia's peas are representatives of genera found elsewhere in the world (eg indigo (Indigofera), coral trees (Erythrina) and rattlepods (Crotalaria). However, there are two groups ("tribes") within the family which are almost entirely Australian.

The main identifying characteristic of members of the "pea" group of plants is the structure of the flower.

The typical "pea" flowers consist of 5 irregularly shaped petals; the "standard", two "wings" and two lower petals joined along their upper edge to form the "keel", as shown in the diagram.

Some Selected Species

1. Brachysema celsianum

The bright red flowers of Brachysema celsianum have very large "wings" and, at first glance are not "pea" shaped.

2. Chorizema ilicifolium

Chorizema ilicifolium is one of the most colourful of the pea family. It is a small shrub.

3. Crotalaria cunninghamii

The green bird flower, Crotalaria cunninghamii is widespread in inland areas of northern Australia

4. Dillwynia tenuifolia

Dillwynia tenuifolia is a plant occurring in small populations in western Sydney and extending to the north coast of NSW.

5. Goodia lotifolia

Goodia lotifolia can be found in moist forests in many areas of Australia.

6. Hardenbergia violacea

The bright purple flowers of Hardenbergia violacea make a colourful display in late winter/spring.

7. Hardenbergia violacea; Pink form

The pink form of Hardenbergia violacea provides a useful contrast to the normal purple flowered form.

8. Ingigofera pratensis

Forest indigo, Indigofera pratensis is found in grasslands and woodlands of northern Australia.

9. Kennedia rubicunda

The coral pea, Kennedia rubicunda is a common, vigorous twining plant.

10. Oxylobium scandens

Oxylobium scandens is a scrambling species which is fairly inconspicuous until the flowers appear in spring.

11. Pultenaea villosa

Species in the genus Pultenaea are the typical "bush peas". This is Pultenaea villosa.

12. Swainsona formosa

Sturt's desert pea, Swainsona formosa is the floral emblem of South Australia.

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