Acacia dealbata

One of these things is not like the other #2

I admire people who can walk through the bush and identify the flora without referring to a field guide. To do this I think you need a good knowledge of what flora should be in the area (that will whittle down the hundreds of choices down to the tens), and then a system for classifying them.

Cootamundra Wattle - easy peasy

Cootamundra Wattle – easy peasy

For nearly a decade I have been trying to learn all the plants on our property (with little success). I’ve started with the acacias. Acacias are divided into six groups based on the shape and form of the leaves and flowers. Using the colour of the flowers is not very helpful! Group 1 acacias contain wattles with bipinnate foliage (as opposed to single leafed). I call them feathery-leaved wattles. Where I live there are only three species with this type of leaf – the Cootamundra Wattle (Acacia baileyiana) (an environmental weed in this area, planted by the previous owner), the Silver Wattle (Acacia dealbata) and the Black Wattle (Acacia mearnsii).

Silver Wattle - a bit trickier

Silver Wattle – a bit trickier

The Cootamundra is easy to pick – SMALL bipinnate leaves and that unique light blue-green colour. The Silver and the Black Wattles are a bit trickier to tell apart. The Silver Wattle flowers a bit earlier but how do you pick them when they are both in flower or both not? I’m glad you asked. You will have to look closely at the rhachis – the stem down the centre of the leaf. Distributed along the rhachis are tiny oil glands. In the Silver Wattle the oil glands are situated AT the point where each pair of pinnates is attached to the stem (pictured above). In the Black Wattle, those oil glands are BETWEEN the spot where the individual fronds meet the stem (pictured below, click photo to enlarge). Tricky, eh?

Black Wattle

Black Wattle

Well, that covers the bipinnate wattles. That only leaves 11 more acacia species and several dozen more trees to come to grips with.

Down but not out

The tenacity of Australian trees to survive in our harsh climate never ceases to amaze me. Our property is steep, the ground rocky with little soil cover and the land is dry. And yet trees grow. What is more astounding is how they will cling to life when most introduced trees would die.down not out gum

An example is a Red Stringybark (Eucalyptus macrorrhyncha) on our neighbour’s property (pictured above). Knocked over in a storm last year, there are enough roots left in the ground to suck up moisture and nutrients so that the branches have become the new trees and continue to grow towards the sun.down not out acacia

Even more amazing is this Silver Wattle (Acacia dealbata) in the valley below our house (pictured above). Split in the same storm as the Red Stringybark, the top of the tree is still happily growing despite the fact that it is at ground level, competing for light with all the grasses, and only attached to the trunk by a thin sliver of bark. In trees, nutrients are delivered from the roots to the branches by a thin layer below the bark called the phloem. Similarly a layer called the sapwood delivers water. As long as these pathways are intact this Silver Wattle will continue to live.