Leaves of Cootamundra wattle (top) and Silver wattle
Leaves of Cootamundra wattle, Acacia baileyana (top) and Silver wattle, Acacia dealbata (bottom).
How to distinguish the weed Cootamundra Wattle from the look-a-like native Silver Wattle.
The Cootamundra Wattle, Acacia baileyana is an introduced and highly invasive species; the Silver Wattle, Acacia dealbata is an endemic species native to Mount Majura and Mount Ainslie. Both wattles have blueish-grey-green leaves and flower early in spring.
They can be distinguished readly by their leaves. The compound leaves are called bipinnate leaves: pairs of leaflets or pinnae (singular: pinna) are arranged along the main leaf stem (rhachis), and pairs of pinnules - the smallest unit of the compound leaf - are arranged along the stem of a pinna.
The bipinnate leaves of Cootamundra wattles have 3-4 pairs of pinnae, the lowest pair is shorter, swept back and embraces the stem to which the leaf is attached. The bipinnate leaves of Silver wattles have 8-20 pairs of pinnae attached to the rhachis; the lowest pair is not swept back.
Photograph Waltraud Pix