March has been a hectic month, and I’m reporting in on the final day again. I haven’t had much chance to get out and about this month, but I did spend a couple of evenings poking around Flowerdale Lagoon and Pomingalarna Reserve at Wagga Wagga, just this week, accompanied by my dad.
Pomingalarna Reserve (aka Pomingalarna Park) is a scrubby hill reserve on the western edge of the Wagga Wagga township, and is named after a Wiradjuri woman from a local legend. The reserve is dominated by White Cypress Pine (Callitris glaucophylla), assorted Acacia species and some rather weedy-looking Inland Grey Box (Eucalyptus microcarpa) and White Box (Eucalyptus albens). The reserve is popular with mountain bike riders and is criss-crossed with trails for cyclists, walkers and horse riders to use. The Wagga Urban Landcare Group have undertaken habitat plantings for Glossy Black Cockatoos (Calyptorhynchus lathami) in parts of the reserve over the past decade, but I didn’t walk through any of these sections on this particular visit.
Many of the wattle species had flower buds forming, so I shall have to head back in a few weeks when they are all in flower and get some pictures to show you all. There’s some amazing diversity in wattle flowers, considering that they can all be simply described as ‘small yellow puff-balls’.
There’s also amazing diversity in wattle leaves, and I was very excited when my dad pointed one plant out to me and asked why it had two different kinds of leaves on it. I was excited because it was a great visual demonstration of the transformation from juvenile bipinnate foliage to adult phyllodes. Many Australian plants have different juvenile and mature foliage, and this is particularly evident on a lot of Acacias. Many Acacias start life with ‘feathery’ bipinnate leaves, and whilst some retain this foliage throughout their life cycle, others develop what are known as phyllodes. Most wattle ‘leaves’ are actually phyllodes – they look like leaves, they function like leaves, but they’re actually modified leaf stems. The transition from bipinnate leaves to phyllodes was really well demonstrated on this one plant, and we could actually see the progression of the leaf development moving along some of the branches, rather like a static conveyor belt, but it proved difficult to photograph. Please excuse the presence of my hand in the photo below, and look closely at the differences in the leaves (remember to click on the pics to biggify).
As you can see, toward the end of the branchlet closest to the tree the leaves are bipinnate, with feathery leaflets branching off of a central stem, which is referred to as a petiole by botanists. Travelling along the branchlet toward the tip you can see the petioles of the leaves flattening out and becoming broader, as the leaflets fall away, finally leaving the adult phyllodes, fully formed at the end of the branch, closest to the camera.
You might also notice in the photo above some round, red ‘bumps’ that are present down the centre of petioles in the bipinnate leaves, and along the edges of the phyllodes in the foreground of the photo. These are nectaries, or nectar glands. You can find these on most Acacia leaves and phyllodes, although they vary in size from species to species, some being big and obvious, others requiring magnification in order to see (thus making them a diagnostic feature for many species). These glands produce nectar as a bribe or reward for pollinating insects, in the same way as nectaries inside many flowers do. The insects are drawn to the plant to collect the delicious, energy-rich nectar, and in so doing they also collect and distribute pollen at the same time, thus helping the plants to reproduce.
Also of note on this visit were the various signs of invertebrate activity we came across. Meat ants colonies and spider holes were frequently underfoot, I found one young eucalypt sapling with large accumulations of insect frass at each trunk/branch junction, presumably caused by borer activity, and some rough patches up one side of the trunk which I was unable to get a good picture of, but which may have been caused by a bird attempting to get to the borers inside the timber.
Not far from the borer damage I found some lovely shell lerps on a leaf. Lerps are protective coverings made from crystallised honeydew, generated by sap-sucking psyllids nymphs. Different species of psyllids produce very different-looking lerps, so I am fairly confident in identifying the ones I found as belonging to a species called Spondyliaspis bancrofti. As with all parasitic species, the survival of the host depends on how healthy it is, with quite healthy trees being able to easily survive a psyllid attack, whilst more stressed trees may succumb. The sapling I found the lerps on didn’t look to be in the best health, but it was only a fairly small infestation, so the tree may survive.
Further up the hill my dad spotted something white in the grass. I admit I would have assumed it was a plastic bag or something if Dad hadn’t insisted on closer investigation, so bonus points to Dad, because it turned out to be something far more interesting than a plastic bag.
Many thanks to Bindi Vanzella (@bidgeewidgee) and Manu E Saunders (@ManuSaunders) on Twitter who helped us to identify it as a ‘tent’ nest built by processionary caterpillars. It would have originally been suspended from the tree it was underneath, and must have fallen at some point.
On the way out we came across a small group of Superb Fairy Wrens (Malurus cyaneus). I’m not sure how well these photos are going to show up, but if you can see it there is a male in non-breeding plumage (dull brown with a blue-black tail) and a female (dull brown with a reddish face) in the first photo. The second photo shows the male’s tail a little more clearly.
The day after visiting Pomingalarna, Dad and I also visited nearby Flowerdale Lagoon. We didn’t stay long but we did find an Australian Pelican (Pelecanus conspicillatus) settling down for the night, and this awesome bracket fungus.