English: Bipinnate leaves of wattle, NSW. Bipinnate leaves, such as this shown here, are 'twice-divided' leaves which consist of small leaflets (pinnules) arising from pinnae arranged along a central axis, the rachis. The wattles, which are largely responsible for the amount of yellow in Australian's vegetation, belong to the genus Acacia. There are more than 70 species in the Sydney region alone and nearly 700 in the country altogether. They range form low shrubs to tall trees. Whenever acacias occur, they are usually present as an understorey - and hardly ever dominate the landscape the way eucalypts do. The wattle has been chosen as the flora emblem of Australia.