Grow Native Cassias for Butterflies

Senna species
Family: CAESALPINIACEAE
If you grow native cassias, you will always have yellow butterflies in your garden.

Butterflies like to hang around their host plants - the plants which have the right kind of leaves to feed the babies of their particular species - and cassias are hosts to a number of butterfly species. It is a great idea to put in a group of these pretty, sun-loving plants, making it easy for butterflies to notice your garden and move in.

Cassias have been subject to one of those name changes that botanists inflict on us, periodically. They are officially Senna species these days, though most people still call them cassias.
 

Three local species, Brush Senna Senna acclinis, and Brigalow Senna Senna coronilloides, and Desert Senna, Senna artemisioides subsp. zygophylla, are all excellent choices for even the smallest garden, as they are easy to keep to waist height by pruning once each year after flowering has finished.

The butterflies you will attract, by planting native cassias, are likely to include

the small grass-yellow,

the large grass-yellow
 
and the even larger lemon migrant
 
and yellow migrant.

Native cassias also seem to bring sunshine into the garden, with their summer-long display of bright yellow flowers.
They are always aware of the sun, these plants, closing their leaves at dusk, and opening them again in the morning.
Sennas are tough, drought hardy plants. Our local species also tolerate all but the hardest of our local frosts. Their lifespan is somewhere between four and ten years. Plants that are pruned, fertilised and watered once a year after flowering (in autumn) live the longest.
They will grow in full sun, where they make dense screening foliage. They are also happy to fit in politely between other shrubs, never overwhelming them, but fitting their flowering branches into the gaps.
 

These Senna coronnilloides are sharing the dappled sunlight under some trees with some wilgas.

New plants are easy to grow at home from seed.

Put them into a coffee cup, cover with boiling water and leave to soak overnight, before planting those which have swelled.

Brush Senna
Senna acclinis

You get double environmental points for growing this local plant. Not only is it a butterfly host. It is also a threatened plant, having lost most of its rainforest edge habitat through clearing. A few plants can still be found growing wild on the western edges of Toowoomba, at sites such as Kingsthorpe Hill and Birdwood Sanctuary, but it is rare to find them in the district nowadays.
It is occasionally mistaken for the Easter Cassia (Senna pendula var. glabrata), a South American plant which fell out of popularity in gardens because of its tendency to grow to large, too fast, too leggy and too weedy-looking. It has never disappeared from the district, though, as it has jumped the fence to become an environmental weed. It may come up in your garden whether you want it or not. The brush senna is a more civilised plant, with a longer flowering period.
It grows to between waist and shoulder height (depending on whether or not you have pruned it), and makes a dense screen.
It may self-seed to some extent, if you are lucky, but a more reliable way of making more plants is to grow them from seed.
(If seedlings come up, and you are not sure whether you have this plant or Easter cassia, look carefully at the edges of the leaves. Easter cassia’s leaves have a narrow gold line around the edge.)


Brigalow Senna
Senna coronilloides

This equally desirable plant loves the heavy black soil to the west of the Range, but is happy on all soils.
Its fine leaflets are blue-green.

Butterfly Season

What a wonderful butterfly season we are having this year.
I suppose you have all noticed that this is a big year for caper whites (Belenois java teutonia)?
This is the butterfly with the fairly plain wingtops, white with black edging,


and the beautifully marked underside which you only notice if you look a little more carefully, or see one at rest.

I don’t think anyone knows quite why they sometimes have a spectacular year like this. We haven’t had one since before the 2011 floods, so perhaps they do better when the weather is dry.
People speak of them “migrating”, which suggests a purposeful journey with a planned end in mind. What they are really doing seems to be more of a random radiation. Perhaps they have exhausted their local host plants and are simply flying away in hope of finding more. They turn up in great numbers in the southern states where the host plants don’t occur naturally. There manage to find the few cultivated specimens, where they can be seen flying in a whirling mass around the plant. The males and females fly in separate migrations, but obviously succeed in meeting up, as they have been seen laying eggs in Victoria. (If they can’t find a caper plant, they lay on unsuitable plants, and the caterpillars die.)
They also fly out over the Pacific Ocean in their many thousands. Odd specimens have been known to turn up as far away as Samoa.
The butterflies breed on our local native caper plants, Capparis arborea, C. mitchellii, C. lasiantha and C. sarmentosa. Like most local butterfly host plants, gardeners rarely plant them, so the butterflies breed in the country and can only be enjoyed in our towns because they are strong flyers who will often drop in for a refreshing sip of nectar in our gardens. (Butterflies with less strong flying skills and migratory urges are disappearing from our urban areas, as they just can’t make the flight from the increasingly distant breeding sites.)
Most of our local native capers grow on country roadsides. They are prickly plants, so are grown only by butterfly enthusiasts, and tend to be cleared from farms and acreage estates by owners who don’t want to deal with the prickles.

They can also be completely defoliated whenever the butterflies have a big breeding year. They bounce back to beauty and good health afterwards, with all the freshness of a well-pruned plant, but the only people who grow them are those who value the cloud of lovely butterflies more highly than a high standard of year-round perfect beauty from their plants.
Roadsides are potentially subject to clearing for road-building, as our population increases, as well as “beautification” by those who prefer a well-mown, neat and tidy road verge to native vegetation. Depending on your personal aesthetic and philosophical viewpoint, a natural roadside environment is a rich and  environmentally productive ecology, or an ugly “hotch potch”. Unfortunately, destroying a patch of biodiversity is very, very much quicker and easier than replacing it, so the people who think nature needs tidying up, and are prepared to do something about it, have a disproportionate  advantage, when it comes to living in their preferred Australian landscape type.
The long-term future may hold fewer of these spectacular caper white population explosions. Let’s enjoy them while we have them.
For more on this butterfly and its host plants, see my posts for November 19, 2009 and December 4, 2008, or simply type the butterfly’s name into this site’s white search box at top left.

A New Way of Identifying Local Plants

It’s always been a problem.
You see a pretty tree in the local bush, or rainforest, or on your new block of land. You want to find out what it is, but nobody seems to know.
There’s a new tool that has just been released this week, that helps with a big chunk of the problem. It is an interactive identification key, on a USB, called:


It’s available from http://rainforests.net.au or http://www.rainforestpublishing.com.au , where you can also see some good illustrations showing what’s in the program.
The plants it covers are trees (including fern trees and palms), shrubs, climbers, and mistletoes. The definition of “rainforest” is very broad. All our local dry rainforest and scrub plants are in there, even those which are technically of "rainforest type", but grow in obviously non-rainforest situations out on the Downs. You’ll find wilgas, for instance.
The program costs $80.00. My first thought, being a frugal body, is that it is somewhat expensive. However, I had a second thought which is that it contains so very much more than could ever be put into in a single book that’s it’s a bargain. For instance there are over 12,000 photos!
The best thing is the key itself. My experience with conventional plant keys is that I can get lost somewhere in the pick-a-path process. This key, having the advantages of computer technology, lets you arrive at an ID from many different angles.
The keying-out process begins with the total list of plants, all 1139 of them, and every time you add a bit of information, it gets shorter, until you are left with the answer to your question.
First you put in what type of plant you have (tree, climber, palm, etc). At once, the list is shortened as other plant types are subtracted from it.
Then you might put in that your mystery plant has pink fruits. All the plants without pink fruits disappear from the list. Put in a few other characteristics that are obvious to you - maybe the geographical area, the size of the fruits, and the length of the leaves, and you may even end up with just your target plant left on the list already!
If you haven’t got there yet, there are loads of other questions you can answer to work towards an ID. At first some of these can look daunting. Is the leaf elliptic, ovate or lanceolate, for instance? What do the words mean?
No worries, clicking on a little icon next to the words brings up an illustrated description of all the leaf shapes, so you can easily find the word that best matches your plant sample.
The plant descriptions are also a help. Each plant name in the list has little icons beside it.
Clicking on them brings up a written description with photos, and a black and white sketch showing important identifying features. The pictures are a help when you have got the list of possible plants down to the last few, but can’t decide which one is your unidentified plant.
The other great thing is that there is a species index. You click on a plant name that interests you, and by the time you’ve read the description and looked at the photos of the whole plant, plus close-ups of the trunk, flowers, fruits, leaves (both sides) and so on, you really feel you know the plant.
Great stuff!

Cuttsia

Cuttsia viburnea
Family: CARPODETACEAE
Now flowering - and what attention-grabbing flowers these are!

In their typical habitat, a shady creek bed in rainforest understorey, these gleaming white flowers led my eyes to a plant I might otherwise have overlooked. The strong honey scent of their nectar-rich flowers was attracting the attention of many insects. Little quiet birds were coming as well, to feed on the insects, making the point that insect-attracting plants have value not only for the insects in their environment.
If fertilised, the flowers of this plant produce heavy seed crops in their little capsules. However,  as with many bisexual-flowered plants, Cuttsia plants are not self-fertile. Separate timing of the maturing of their flowers' male and female parts means that the flowers of isolated plants remain unfertilised, despite visits from many suitable pollinators.To produce seeds it must grow close to a friend or two.

A solitary plant makes a lovely garden specimen, but seed production matters if we are trying to re-introduce lost ecosystems or reproduce something like a natural environment in our own gardens. Don’t overlook the possibility of planting several quite close together if space is limited. This would result in something resembling a multi-stemmed large shrub or small tree.
Cuttsias grow best where there is constant soil moisture. Where this can be provided, this is an excellent plant for an understorey situation or a shady corner. Established plants do tolerate some drought, but would need to be helped along if the dry spell is prolonged.
They are claimed to be frost hardy.

There have been a few attempts to give this plant a “common” name. Some people call it elderberry (but it’s not an elderberry, and Australia has several genuine elderberry species which might even be growing side by side with this plant in the wild). Others call it native hydrangea (but it isn’t related to hydrangeas, and doesn’t resemble them much, as you can see). The name “native hydrangea” is more commonly used for the closely related Abrophyllum ornans, so like “elderberry, is not a particularly practical one. Others call it honey flower, which is very appropriate considering its strong nectar scent. Unfortunately, if you say “honey flower”, people are more likely to think you are speaking of another Australian plant, Lambertia formosa. Falling back on the botanical name, as we have done for grevilleas and quite a few other Australian plants, seems the best solution to achieving a user-friendly name for everyday use.

Bellfruit and the Fire Ecology.

Codonocarpus attenuatus
Family: GYROSTEMONACEAE 
This is a surprising plant.
Its soft leaves make it look a rainforest species, but this may not be the case.
There are records of it being found in rainforests. However if they were seen when not fruiting, it’s a fair chance that the plants were actually bellfruit’s rare and endangered relative, Gyrostemon osmus, which was generally unknown until it was studied and named in 2005. It looks very like bellfruit, but has seed capsules that open along a dorsal split, unlike bellfruit capsules which drop their seeds out of the bottom.
The remainder of bellfruits's relatives, both Codonocarpus and Gyrostemon species, are plants of the desert or dry country out west.
Bellfruit itself is “Mr In-between”. Found in coastal and sub-coastal sites, it hangs about on the edges of dry rainforests and in disturbed areas hoping for fire to help its seeds germinate.
Australian ecosystems can be broadly divided into two groups – those (like rainforests and vine thickets) which are damaged and reduced by fire, and the “fire ecologies”, which depend on fire for good health. The latter are populated by plants which thrive with regular fires, and may even depend on them for the species’ long term survival. If the rainforest specimens are all actually Gyrostemon osmus, then we can place the true bellfruit, Codonacarpus attenuatus on the "fire" side of the fence.

The plants above, which I photographed a few days ago, were in a typical site. It is a large council-owned reserve in the Merritt’s Creek Road area which was covered with fairly open vegetation until it was given a clean-up burn in 2010. The result, in a mere four years, is this extremely thick growth of wattles Acacia neriifolia (another fire-loving plant) and bellfruit (centre plant with light grey trunk). Loving the fire, they came up like hairs on a cats' back from seed lying dormant in the soil.
The scrub is now about 6m tall. Crowding has resulted in tall thin plants with bare trunks and dense leafy growth at the top only.
Not all the bellfruit trees in the scrub have seeds on them, because the species has separate male and female plants.

                                                                                                                       Photo by Dougal Johnston
There are, however, plenty of male plants to ensure fertilisation of the female plants. They were heavily laden with their little green "bells". As the species is wind-pollinated, there is always a chance that having too few plants in the area might result in uneven pollination, with pollen failing to reach all the female flowers. This is clearly not the case there!
Bellfruit trees are not often grown in gardens, largely because they are not often available for purchase. Seeds are difficult to germinate, but are known to do better if soaked in smoke water.

Gardeners would need to put in several plants, to be sure of having specimens of both sexes, if they want to get the ornamental "bells".









Specimen plants grown in the open are likely to be as little as one third the height of the plant shown at left, and to have canopy almost to the ground.





















In gardens, a useful planting style can be to put a small group of bellfruit close together. This can result in plants (of both sexes) forming a united canopy, looking rather like a multi-stemmed large shrub.

Like many other fast-growing pioneer trees, bellfruits probably have a relatively short lifespan.

Foambark Tree

Jagera pseudorhus
Family: SAPINDACEAE
These beautiful trees are showing off their seeds in the local rainforest at present.

Photo by Glenda Walter
I was sent this photo by a friend, who took it in Brisbane, but the plants can also be found locally at Goomburra, Ravensbourne, and the Bunya Mountains.
Foambark is a fast growing tree, usually reaching no more that 10m in cultivation. It has an attractive shady canopy, inconspicuous white flowers in spring, and these lovely fruits in autumn. They gleam redly as the sun catches them.
Unfortunately, the stiff little hairs on the seed capsules break off when handled, and can cause considerable skin irritation. This is something to be considered, before planting it as a garden tree. It is not suitable for a site where children might be picking up fallen capsules.
The plant’s common name comes from an Aboriginal use for it. The bark contains so much saponin that it can froth from any little injuries, in heavy rain. This means that, if thrown in water, branches and leaves de-oxygenate the water, temporarily stunning fish for easy catching.
I used to think the tree was named for the Jagera tribe of Aborigines, and thought that it was a remarkable example of white settlers honouring the original owners of the land.
Not so, however. It was named after the Dutchman who discovered the original Jagera species in Indonesia, and it is just coincidence that there is another species in the Jagera tribe's territory. Apparently Jager means Hunter, and is a relatively common Dutch surname.

Strap Water Fern

Blechnum patersonii
Family: BLECHNACEAE 
This fern often attracts attention in damp rainforests as the it tends to grow on the earthen faces of path cuttings, on the uphill side of paths in our wetter local national parks along the Great Dividing Range. It also grows beside or in streams, and would do well in red soil gardens, in positions where it can have mulch, and shade for at least half the day.

I imagine it might be a particularly suitable plant for one of those fashionable "green walls" - provided it faced south or east and was shaded from the midday summer sun. It also grows well indoors and in areas with very low light levels.
Strap water fern grows better if watered in dry periods, but, like all our hardy local ferns, it tends to be prone to pests and diseases if the dampness is overdone. In nature, it tolerates the long dry periods of our climate, and even some light frosts. It doesn’t have to be a pampered pot plant or fern-house specimen.
The fronds of this rather delightful plant seem to be suffering an identity crisis. The simple strap  is the most common shape, but a single mature plant might have some straps, and some fronds with varying numbers of lobes.
The foliage (once the new pink fronds have dulled to green), is a rich, dark green.

The fertile fronds are very narrow indeed. It is common among ferns for the fertile fronds to be longer and skinnier than infertile ones, but strap water ferns carry the contrast to an exaggerated degree.

 




Here are two infertile fronds beside two fertile ones.
















The first time I saw this plant's narrow fertile leaves, with their heavily spore-encrusted edges, I mistook them for diseased fronds! Then I examined their backs, and realised they were heavily rimmed with spores.


Grown by itself, a single plant forms a rosette.

Thorny Yellowwood

Zanthoxylum brachyacanthum
Family: RUTACEAE
What is this plant’s future?




Here’s the trunk of a young thorny yellowwood, showing what a prickly little fellow it can be. Those thorns are sharp!
Like human teenagers, it will grow out of this prickly stage.
In older trees, the thorns thicken up and lose their sharp points. You can put your hand on the trunk of a mature tree, quite comfortably, even though it is still covered with the fat old thorns.
Notice the young vine in the photo above. Perhaps this yellowwood sapling will grow into a strong tree, up to 15 metres tall in its rainforest environment...







 

 

...or perhaps its future will be like that of the plant at right.


This one’s broad thorns tell us that it is actually quite an old plant, but life in the stranglehold of its encircling vine has not been easy. It hasn’t reached the size we might expect for a plant of its age.











Here's the trunk of a large specimen.


Thorny yellowwoods are pretty plants. Grown in optimum conditions, they become attractively shaped trees with dark, dense canopies, like this one at Peacehaven Botanic Park which I photographed three years ago.
 
Thorny yellowwoods grown in gardens, where they don’t have to compete with tall trees for light, will never reach the height of their rainforest relatives. 6-8m is a more likely maximum for a garden specimen. The plants are dioecious, so the best way to grow them might be in a grove of 3-5 trees, planted close that their canopies unite into one. This would give a high likelihood of having plants of both sexes.
They contribute to the environment by hosting swallowtail butterflies, and (in the case of fertilised female trees) producing shiny black seeds in bright red follicles to attract birds.

The Peacehaven plant is female, as these flowers show.

Australia has six Zanthoxylum species, all but this one being plants of the tropics. They all have aromatic bark, leaves and seed follicles.
Spices have been produced from most of the 250 or so overseas species of Zanthoxylum. For example, Sichuan pepper, one of the ingredients of Asian five-spice powder, is produced from the red follicles of any of several Zanthoxylum species. Young leaves and shoots of other species are used as garnishes or as an ingredient in a strongly flavoured pesto-like paste. Even the bark is used in small quantities for flavouring.
I am not aware that our local species has been used for any of these purposes, but the potential may be there.

The Rutaceae Family
This family is well known for the strong smell of its members' aromatic leaves.
Some smell wonderful, and some quite appalling.
It is a Gondwanan family, only one branch of which, (the one containing citrus fruits) has spread to any extent into the Northern Hemisphere.
Knowing the family of a plant can help us to know how to manage it, as a garden plant. Australian Rutaceae would rather you didn’t fertilise them. They are well-adapted to low-nutrient soils.
To find blogs on other local Rutaceae, search for the family name in the white search box at top left.

Leichhardt’s Ironbark

Bridelia leichhardtii
Family: PHYLLANTHACEAE
It’s interesting to see this tree at work.

Plants need something or someone to distribute their seeds about for them. Without this assistance, they would have thousands of babies with nowhere to grow but under their parents.
This tree, with its red fruits, is advertising for birds to do the job.
What it wants is for them to eat its fruit, clean its seeds, and deposit them, with a little dollop of fertiliser. It produces large numbers of fruits, so there is always a good chance that some of them will be dropped in a suitable site for growing.
Birds are attracted to the colour red. These particular  fruits are slightly translucent, and glow brightly in the sunshine, no doubt looking particularly appealing to any fruit-eating bird that flies past.
When it stops at the tree, however, it soon discovers that the red fruits are not yet ripe, but that the several black fruits scattered amongst them are soft, succulent, and no doubt delicious. Having learned this, birds are likely to return to the tree again and again during its fruiting season, spreading the fruits much more widely than they might have in just a few gorging sessions.
It is usually seen as a shady small tree, but can grow to have a prominently fissured trunk of as much as a 30cm diameter. It can also be a large, multi-trunked shrub.
It likes a well-drained soil, and can usually be found growing on hillsides, in red or black soil country.

Nodding saltbush

Einadia nutans subsp nutans (Rhagodia nutans)
Family: CHENOPODIACEAE

Now is a good time to go and look at these saltbushes, in Irongate Conservation Park.
This knee-high plant is fruiting profusely, with both red and yellow-fruited plants – notice their brilliantly coloured matching calyces – growing side by side.



These are such wildlife-friendly plants that it is a pity we don’t see them more often in gardens. Birds, particularly silvereyes and little honeyeaters, love the berries, and many animals including lizards eat the leaves.
The plant is known as "climbing saltbush" or "nodding saltbush", but both are rather unsatisfactory common names. It doesn't really climb, though sometimes it will lean a bit.If it is planted in the shade it will use the support of other plants to grow a bit higher than it would if growing in full sun.
It's a bit of a stretch to say it nods, too, though a larger-than-average raceme of heavy fruits will do it.
If grown in full sun, the plants grow in neatly rounded shapes, and as is demonstrated in the wild at irongate, in large numbers they make an effective, frost and drought hardy groundcover.
Ruby saltbush Enchylaena tomentosa, and fragrant saltbush Rhagodia parabolica are also fruiting in the reserve at present. 
The abundance of saltbushes at irongate is appreciated by the little saltbush butterfly (Theclinestes serpentata), a creature that can only breed on saltbushes. It is shown here in its favourite head-down pose.
 
There are plenty of them in the reserve, and if you watch them very closely you may notice their tendency to rub their back wings together in a circular motion. It is thought that this attracts the attention of predatory birds away from their heads, towards the rear margins of their wings, where with a little imagination you can think of the little tails as antennae, and the darker spot as an eye. It seems to work, as you often notice this butterfly and its relatives with damage on their rear wings, the part of their bodies they can best afford to lose.
As they fly, you may get a glimpse of the little patches of iridescent blue on the upper surfaces on their wings.
Their caterpillars are carefully guarded by various species of ants, including the meat ants (Iridomyrmex sp.) which are so conspicuous on Irongate’s paths. In exchange for their care, the ants “milk” the caterpillars for a sweet exudate.
Saltbushes are somewhat resistant to burning, so are desirable plants to replace woodchip mulch, where there is a concern that the mulch might lead a fire into a garden.
Obtaining saltbushes for garden use can be difficult, as they are rarely offered for sale. Growing them from seed or cuttings may be the best option.
Saloop also goes by the common name of “berry saltbush”, but this is not a very useful name, as it is applied to a number of other saltbushes as well.
Irongate Conservation Park is between Mt Tyson and Pittsworth. 
To get there from Mt Tyson, head west out the main street. Near the property called Adora Downs the road makes a right-angled turn to the left (south). Follow this until it hits a T-intersection. Turn left, and in about 200 metres you see the Irongate Hall on the left. Turn right (south) almost immediately (into Wallingford Road)after that, and follow the road (which makes a bend to the left) for something like 3.5k until you come across the reserve on your right. Keep your eye out for the iron gate that marks the place.

The Family Chenopodiaceae     (The Saltbush Family)   
The saltbushes which are such a characteristic part of inland australian scene, are part of a  world-wide plant family. It includes beets and spinach. Many of its members are adapted to growing in soils with high salt levels, so can be found at the seaside.
Leaves of the Australian saltbushes are edible, fleshy and often salty, though their saltiness depends on soil salt levels. The inconspicuous flowers are five-lobed, and many species have showy fruits which are edible and sweet.   
It’s an increasingly popular family, and not just because its members are happy growing in the salt-ruined soils that result from our nation’s irrigation practices. They are becoming better appreciated as good-looking easy-care garden shrubs as well.   Saltbushes are all fire-retardant. Most are outstandingly drought hardy, never needing watering once established - though just a bit in the hard times does keep them looking good.    There are 200 Australian species, of Chenopodiaceae, including some horrible weedy-looking things, and some that are unbelievably prickly.     However there are many good ornamental ones too. Most have silvery leaves which make them useful in designed landscapes, and many have bright berries. 
To find other blogs on members of this family, search for Chenopodiaceae in the white search box at the top left of the page.

 

CAN YOU PICK THE MISTLETOE?

 Amyema cambagei
 Family: LORANTHACEAE
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?




BULL OAKS AND SHE OAKS
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!)

Harlequin Mistletoe

Lysiana exocarpi
Family: LORANTHACEAE
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?

Woolly Frogsmouth

Philydrum lanuginosum
Family: PHILYDRACEAE
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!

Ivorywood at Anduramba

Siphonodon australis
Family: CELASTRACEAE
I saw this pretty tree on red soil at Anduramba a few weeks ago.


Having only ever seen the species growing in scrub, I was interested to see how it shaped up as a plant grown in the open, in a paddock which it shares with cattle.
It is certainly a pretty specimen, especially laden as it is with its aromatic fruit.

This plant is probably very old, despite its small size. The species is slow-growing at the best of times. It was probably not much smaller than this when the original scrub was cleared from around it, a century or more ago. Like so many dry rainforest trees, it would have the ability to survive happily, but make little growth in a rather harsh habitat like this.
Ivorywood is one of our disappearing trees, easily cleared, and taking several human lifetimes to replace.
We all love big trees, but should remember to value those which are not naturally very large. Action groups wanting to save “significant trees” are sometimes found fighting tooth and nail to save 30-year-old gumtrees, while letting ancient treasures like this disappear without a word of protest.

For more about this plant, see Dec 2009