Sunday, March 23, 2014


 Amyema cambagei
With a careful look, you’ll find the tangled-looking foliage of a needle-leaf mistletoe Amyema cambagei among the vertical branchlets of its host bull oak, Allocasuarina luehmannii. I photographed it  this morning, out near Kulpi.
These mistletoes are flowering their little hearts out at present. they can be found on bull oaks, and on belahs (Casuarina cristata).

Here is a closer look at the flowers.There is a bit of shortage of nectar in the wild, at the moment, so these blossoms were very popular with a wide variety of insects.

The Family Loranthaceae. (The Edible Mistletoe family)

Bull Oak and its Galls
Allocasuarina luehmannii

Though not usually thought of as a tree of the eastern Darling Downs, this plant can be found here.
It doesn’t like our dominant soil types, the red and black soils, high in clay, that are derived from basalt bedrock. Geologically speaking, however, basalt is a relative late-comer to the area. It arrived here only some 35 million years ago, as lava welling up through cracks and vents, and spreading to cover an older, sandstone-based landscape, and the rich soils which have formed from it - red where they have weathered in situ, and black where they were washed further afield into what was once an upland swamp - are the soils that make our area famous.
The sandstone still shows through at the surface in some spots, though, and that is where we can find bull oaks. Some examples are: between Goombungee and Meringandan, in the Silverleigh Road area, North of Kulpi and around Peranga, and around Leyburn.
Bull oaks are distinguished from the other local members of the casuarina family by their rather open, light green, upright branchlets. Small trees look as though they have all been carefully gelled and combed upwards. Older trees may have drooping branches, but all the branchlets end with an upward lift.
A curious characteristic of these trees are these rather beautiful galls. They look like some kind of woody fruit, but are actually formed as a result of an insect, laying an egg on a branch. The tree responds by growing this surprisingly complex gall.

Cutting it open reveals a little grub. Note its cozy little cave in the gall, with a hole for excreta at the tip.

I know almost nothing about gall insects, though I am fascinated by the beauty of the galls they are able to create on their host plants. When I originally published this post, I was able to track down that the insect (see above and below) was a species of Cylindrococcus, but mistakenly thought that the tiny red insects were some kind of parasitic mite.
So I am delighted to have been set right by someone who was kind enough to write a comment saying "The insect is indeed a Cylindrococcus sp. The red guys are crawlers or the offspring of female who spends her life entombed. The crawlers exit the hole and a dispersed by wind."
 Not "mites", but babies! Isn't nature wonderful?

What’s the difference?
Most Casuarinas and Allocasuarinas (until recently all called Casuarinas) are known as “she oaks”. This was an early colonial name, and was insulting both to the trees and to women.
The timber was thought to resemble the familiar oaks of England Quercus robur, whose hard, heavy wood was used for shipbuilding.  The timber of these colonial “oaks” however, was not good enough for that purpose, which was frustrating in a colony whose first expansion was along the coast, and which therefore badly needed boats and ships. So the local “oak” was given the derogatory appellation “she”.
The name “bull oak” defies explanation.
It usually used for just one species, now called Allocasuarina luehmannii, though in a few localities it is applied to the plant more often known as black oak, or black she oak -  Allocasuarina littoralis.
A modern myth, to be found on the internet, is that Allocasuarina species (plants whose seeds are shiny red-brown or black) are “bull oaks” and that Casuarina species (with dull grey or yellow-brown seeds) are “she oaks”. This doesn’t stand up to inspection, however. There are about 58 Allocasuarina species, and most are called “she oaks”.
So why are they “bull” oaks?
Do you know? (Tell me, if you do!)

Saturday, March 22, 2014

Harlequin Mistletoe

Lysiana exocarpi
We found this pretty mistletoe growing on Bull Oak Allocasuarina luehmannii at Lake Broadwater yesterday.

It is a delicate-looking little plant. Below, you see its haustorium, the closest it gets to having a root, at the point where the little woody branches of the mistletoe join a a small branch of its host. Like all mistletoes, it is only partly parasitic. Its own leaves produce its food, by photosyntheses, but it depends on its host for the theings that most plants get from their roots - water and minerals.


Its long narrow leaves are a little broader than the bull oak's branchlets, but still manage to hide themselves there very effectively. The plant is usually only noticed when it produces its gaudy flowers.
 The flowers at Lake Broadwater were later in the season than I would expect. Earlier flowers had resulted in these pretty fruits.
I am uncertain whether it really belongs on this blog, as I have only seen it on bull oaks near Dalby, on both sides of the Condamine - and they are plants of sandy rather than basalt soil. However it has been known to grow on a wide variety of other plant species Including some introduced ones (olives, oleanders) and on other mistletoes.
I think of it as a western mistletoe, but I am aware of an early record of it having been recorded as growing on a scrub boonaree Alectryon diversifolius at Gladfield (near Cunningham’s gap).
Can any of my readers tell me of other places on the Eastern Darling Downs where it grows?

Tuesday, March 11, 2014

Woolly Frogsmouth

Philydrum lanuginosum
Well now, here’s an unusual thing! This plant was named in 1788 from Joseph Banks’ 1770 collection, and hasn’t had a name change since! There has been so much fiddling about with the botanical names of Australian plants that it comes as a surprise to find something that has been stable since the beginning.

I photographed these plants at the Gumbi Gumbi Garden out at the University of Southern Queensland. They are fast-growing perennials, that like to grow in shallow water or constantly wet mud.

These are rather young plants. They will die back to their roots each winter, which helps them survive light frosts. Come spring, they will put up fresh leaves, and flower continuously through all the warmer months of the year.

The cheerful yellow flowers open progressively up the spike, so these plants always have some flowers on display.
In larger water bodies, woolly frogsmouth can be left to naturalise, with new plants growing from seed. It is a useful habitat plant, and helps to stabilise the banks at the waters edge.
If it is being used in a garden pond, gardeners are likely to want to reduce the size of the root - quite an easy matter - each winter. The older roots should be taken, with the more vigorous younger roots being left to grow for the next season’s display.
If grown in an underwater pot, they need repotting at the end of each season.
Fast-growing plants like this are very useful in a pond which is prone to unsightly algae. The woolly frogmouth plant’s fast growth uses much of the excess nutrient in the water, which would otherwise feed the algae. Annual removal of dead plant matter and the extra roots transfers the nitrogen to the compost heap, where it is better appreciated!