Saturday, June 26, 2010

Woody Bracket Fungus

Ganoderma australe
I photographed this beautiful bracket fungus, on a dead tree-stump at the Bunya Mountains, yesterday. Isn't it a lovely?
The brackets of this species of fungus may last for 10 or 15 years, and renew themselves annually with a fresh, white, spore-producing layer like the one shown here. It coats the rim, covers the underside, and drops fine, red-brown spores. You can see in the photo that they are so plentifully produced as to have covered the leaves below with a dusty-looking layer. The rim fades to brown over the year, and will be covered with another new layer around this time in 2011.
These enormous bracket fungi feel woody to the touch, and rapping on them with the knuckles makes a sound like knocking on a door.
Brackets of this kind, like mushrooms and toadstools, are “fruits” which reveal the presence of the hidden body of the fungus. The body called the “mycelium”, consists a network of white, thread-like “hyphae”. In the case of a partially-decayed stump like this one, the mycelium would be well-established throughout the dead wood, busily engaged with its important job of decomposing it. The nutrients which are released, as the old wood decays, will be taken up by new, growing plants. Some of these will be new trees to replace this ancient corpse, but even the nettles in the photo, lovers of fertile soil, are enjoying the benefits provided by the fungus.
Ganoderma australe is native to tropical and sub-tropical countries around the world, reminding us that “australe” means “southern” (not “Australian” as is sometimes assumed.) It actually occurs in the more northerly parts of Australia. A great deal of the world’s botanical science has been done from a Northern Hemisphere perspective!
I once had one of these lovely fungi growing on a dead tree-stump in my garden, and was disappointed when my neighbours’ children knocked it off. I have discovered, since then, that this species of fungus may not live on dead wood alone so have become less keen on it as a garden resident.
There are many kinds of fungi that can eat the centres out of living trees. The heartwood - the best and strongest timber in the centre of the tree - is no longer alive, so is fair game to anything that eats dead stuff. This makes fungi unpopular with anyone who is growing trees for their timber, but popular with the many species of wildlife that need the fungus-created hollows for survival. Trunks shaped like hollow pipes can actually be stronger than solid ones, so these fungi can actually prolong the life of trees, too.
Apparently there is some doubt about whether this fungus species really does harm the sapwood, which is the living, growing part of the timber surrounding the heartwood. It colonises wounds in sapwood, but the jury is still out on whether it has any responsibility for killing living tissue. If it does, however, it would certainly do the trees no good at all!

Saturday, June 19, 2010

Briefly Famous

in a small way...
Last week, an article about this blog appeared in Toowoomba’s local newspaper, The Chronicle.
I enjoyed the process of getting it there.
I was emailed by a reporter called Megan Masters, who had stumbled across this site, and asked me if I’d help her with an article about it. We agreed to meet at Peacehaven Botanic Park at Highfields, because I thought any readers of the Chronicle who were not already aware of this new botanic garden would be interested to know about it. I find it exciting that Toowoomba, after years of having a very nice park which is labelled “Botanic Gardens”, but is nothing of the sort. (A real botanic garden is a place where plants are being trialled and studied, and the public can learn more about them). That Peacehaven features a good range of local native plants, many of them never seen growing in any garden in this district before, makes it a garden worth knowing about.
We met out there on the Queen’s Birthday holiday, a cold blustery day. Megan turned out to be a very likeable girl , able to maintain a good conversation about the plants even though the topic of local natives was obviously new to her.
The newspaper-making process must be a difficult one. Such a lot of pages to be filled every day! Such pressure to produce quantities of relevant and interesting reading matter in a short time! So many people in the chain between the interviewee and the finished product delivered to our doorsteps. It’s not surprising that detail and accuracy are sometimes a little sketchy.
Fortunately, perhaps, I have enough life experience to know that newspaper articles are often surprising to the people who are their subjects, so was not fazed by its few peculiarities.
Megan went to a lot of trouble, for instance, to take a photo which would show that it was taken in a botanic garden, posing me with my hand on one of the labels which tell visitors to Peacehaven what plant they are looking at. No doubt this point was
lost on whichever person simply cut off the bottom of the photo.

The plant was the Glossy Acronychia Achronychia laevis - See March 2008 for a description and pictures of its very pretty fruits.

I suspect that their wording may suffer similar indignities.
The article also stated that I had “penned a book on the 30 or so local native varieties”. There should be an extra zero on that figure, but I was puzzled by it, as I don’t think we discussed the subject at all.

My book, by the way, is available at Dymocks Bookstore in Margaret Street, Toowoomba, and sells for $30.00 or so. (Perhaps that’s where the “30" figure came from?)

It wasn’t a bad article, all the same.
So thank you, Megan.

How Many Local Native Plants Are There?

When I first proposed putting out a book on local native species, one of my friends was embarrassed for me. I asked him to guess how many there were, and he thought there might be fifteen. So the Chronicle’s estimate (above) is a generous one by comparison.
When I put out my book “Toowoomba Plants”, I included in it 274 trees and shrubs, and 19 mistletoes. These were all plants growing naturally on the basalt soils (red and black soils) of an area roughly bounded by the border between Queensland and New South Wales, the great Dividing Range, the Bunya Mountains and the Condamine River.
It is not the full range. Because the topic of the book was “natives of the region suitable for gardens”. I left out plants with names like “blind-your-eye” and “giant stinging tree”, any whose fruits were known to have poisoned children, and any others which I just didn’t like the look of. There are also quite a few desirable plants which I missed, simply because I didn’t know about them at the time.
My second work-in-(rather slow) progress is intended to be an “everything else” book - limited only by the suitability and desirability of the plants for garden use. I am having a problem, however. There are just so many vines, flowering annuals and perennials, orchids, lilies, bulbs, ornamental grasses, rushes, sedges, reeds, saltbushes, and water plants, native to this area, that I can’t possibly put them all into one book. I’ll need to be rather ruthless and select only the ones which I think are the best...
So how many local native plants are there overall? Well I’m not going to get into counting them, but my guess is that something like 3,000 of Australia’s estimated 25,000 native plants occur naturally here. The same situation would apply almost anywhere in the country. Some areas are richer, of course, and arid areas are poorer, but on the whole, no matter where we are in Australia, it would be possible to make an interesting and diverse garden using only local natives.
I think the difficulty that Australians have in accepting that our own flora is so rich and diverse is a leftover from the attitudes that came with our earliest white settlers from Britain, and has never been completely laid to rest.
The British flora was largely wiped out during the ice ages. When the climate began to warm up, plants began to creep back in from the south. As global warming, meanwhile melted the ice, and sea levels rose, and when the English Channel filled and cut Britain off from Europe, (about 10,000 years ago), there was a native flora of around 270 species - about the same as modern Scandinavia. Since then, with seed that has blown in or drifted across, the number of plants generally agreed to be native to Britain - those not introduced by humans - has increased to about 1500.
Of these, only 36 are trees, and there are a further 8 large shrubs.
For the British, by the time Australia they sent their first emigrants to Australia, it was taken for granted that the only way to have interesting diversity in their gardens was to fill them with imports.
We have inherited this attitude, and non-native plants are still being imported into our country at a great rate, often to fill garden niches which could have been better filled by a native - had our gardeners only taken enough interest in the natives to find out what they were. It is now estimated that we have introduced 27,000 plant species to Australia in the last 222 years - more than all our native flora put together!

Saturday, June 12, 2010

The Perfect Windbreak

Scrub Wilga
Geijera salicifolia
It was so cold on the Darling Downs west of Toowoomba yesterday! The weather report told us the maximum temperature was 14°, and there was a dry, bone-chilling breeze.

However at Irongate Reserve, in the sunny clearings sheltered by the scrub, the weather was delightful. The little birds and butterflies were going about their business as usual, and we felt we could ignore the wind, which was merely providing the musical accompaniment, singing its she-oak song well above our heads.
One of the most effective windbreak trees at Irongate is the scrub wilga.
(Don't confuse it with the very narrow-leaved common wilga, Geijera parviflora, which also occurs at Irongate, but is better known from the plains further west).
The scrub wilga’s great virtue is the density of its dark-green canopy, which it maintains year-round and through the worst droughts. Like so many of our dry rainforest/vine scrub species, scrub wilgas have very deep roots which make use of deep-down groundwater. This lets them be even more resilient in droughts than some of our toughest eucalypts. Over the last few years we have seen Eucalypts dying in paddocks west of Toowoomba, while the nearby “scrub trees” were looking as lush and green as ever.
Here are some roadside specimens growing near Mt Tyson, showing the typical canopy-to-the-ground formation of younger trees, which makes them such good windbreaks. As you can see, they are very happy snuggling up close to the mountain coolibah Eucalyptus orgadophila, making a little clump with obvious bird-appeal.

This garden-grown specimen at Gowrie Junction is known to be 27 years old.

With age, the plants develop into pretty little shade trees. I had thought that pruning by cattle must help with the shape (as pruning by sheep does with the common wilga) but I have been assured by a cattle farmer that cattle won’t eat the leaves of scrub wilgas. They are often left in paddocks as shelter for cattle.
This one has had a hard life, with the soil around it well-compacted by stock.
Paddocks in this district were first cleared about 1880, and it is possible that this tough little tree has been roughly this shape and size for 120 years or so. With many of our vine scrub tree species, growth in tough conditions is very slow indeed, and some very old trees are deceptively small. If this one became part of somebody’s garden, and its soil give a bit of extra care, it would probably start to grow again.
Like many of our local native trees, scrub wilgas are very long-lived. The one at the foot of this article grows at at Gowrie Junction. It has never been dated, but could well be 300 years old.
Don't believe the story - usually told as a justification for planting foreign species - that Australian natives are "short-lived"! (It's partly true, of course. The short-lived species are indeed short lived!!! However, only someone who doesn't know much about Australian natives could think that Australia is more richly endowed with short-lived species than any other part of of the world.)
I imagine, though, that a gardener who wanted a little shade tree, could discourage the early tendency to low branching, by judicious use of the secateurs.
Scrub wilgas have a long flowering season. They were beginning to come out in early April, and are at their best around the district in June and July. They are a mass of flowers at Irongate at present, providing food for insects, which in turn provide useful over-winter food for many little birds. The shiny black seeds which follow will provide a further food source.
Botanists tells us that there two varieties (a broad-leaved one, var. latifolia, and a narrow-leafed one, ver. Salicifolia) however here above the Great Dividing Range we notice that there seems to be a continuum. Close to the range they are broad-leafed, and as we move west they become progressively narrower in the leaf.

This is what the leaves look like at Highfields....

...and this is a photo I took at Jondaryan in April. Note the much narrower leaves....

...while the ones at Irongate are somewhere in between.

This picture shows the deep grey twiglets, which, together with the dark canopy, give the whole tree a rather dark look from the far. This must be part of the reason why the local common name for this tree is “black alley”.

The crushed leaves have a delicious plum-pudding smell. This plant is in the same family as citrus trees, and like them is a host plant for our largest native butterfly, the orchard butterfly (Papilio aegeus).
I am told that the butterflies grow larger on their native host plants than they do on introduced citrus species.
Irongate Reserve is in Wallingford Road, between Pittsworth and Mt Tyson.

One of Toowoomba’s Significant Trees

Scrub Wilga
Geijera salicifolia
Does our fair city have a register of significant trees? I have never heard of it, but there may well be one, as it’s the kind of thing that a city which prides itself on its “garden city” reputation could be expected to have.
If so, this tree must certainly be on it. Beside being a lovely plant, it is very unusual, in this city where camphor laurels are so highly valued, in that it is a local native species obviously doing the demanding job of being a street tree, with flair.
Note the neatness of the interface with the ground. The root system of these trees is a deep one, with none of the pavement-heaving surface roots which can be such a problem with trees native to wetter climates.
This tree is on the corner of West and Taylor Streets, and it is good to see that it has been given the respect of a gravelled surface near the trunk, allowing rainfall to penetrate the soil where half the tree lives.
This particular tree is a mass of flowers at the moment. The native insects and birds it is attracting show us that here is a good example of a city tree which is pulling its weight for the environment.
(It’s a butterfly host tree, too)


Casuarina cristata
The wind’s song at Irongate last weekend was lovely. The sound of the wind in the she-oaks is a quintessentially Australian sound, part of the atmosphere of the bush. This Irongate tree is a belah, one of the toughest and most drought-hardy of she-oak species.
The green parts of Casuarinas are neither leaves nor needles, but little green branchlets. You'll notice that they have small joints along their length. Break one apart by pulling both ends, and you will see tiny “teeth” on one of the broken ends. These are all that has been left after evolution has dealt with the “leaf problem”.
The problem, for a tree which wants to survive in a very climate, is that leaves lose water. She-oaks have adapted to drought by the simple expedient of getting rid of them.
They still need to photosynthesise, however. This job, making food out of the carbon in the air, is usually done by leaves, which are green because they contain chlorophyll, a substance essential for the process.
So the branchlets have taken over the chlorophyll, and the job and the job of making food for the tree.
Belahs are dioecious. In the season, the tiny male flowers encrust the male trees with old gold. The reddish female flowers (and these seed capsules) form only on female trees. They grow inside the canopy on the branches.
Belahs tolerate a wide soil pH range, and are the she-oak best suited to the alkaline black soils of the Darling Downs. They are among the faster-growing of our she-oaks, and make good windbreaks. When young, their foliage reaches to the ground, but for a long-term windbreak they should be planted with lower-growing bushy species, as they do eventually develop tall trunks.

Casuarinas and Allocasuarinas
These are all trees of a very ancient type.
Apart from the conifers, they are the only native Australian trees to be wind-pollinated. (Wind-pollination was the first kind of pollination to evolve. Fancy techniques using insects came later, during the age of the dinosaurs.)
These wonderful trees grow very well in poor soils because they can make their own fertilisers - and they do it better if you never fertilise them. Like legumes, they can develop nitrogen-fixing roots. Their ability to do it depends on their roots finding the right soil bacteria, so the plants grow better if the seedlings are planted in a little “mother soil”, from around the roots of established trees, which contains the right bacteria to get them started.
Casuarinas go one better than legumes, however. They can also access help from mycorrhizal fungi, which co-operate with the tree to grow a dense mat of extra root-like structures. These occur seasonally, and resemble the famous “proteoid roots” of Grevilleas and their relatives. They help the tree with the uptake of phosphorus and minerals - but can result in poisoning of a tree if it has these good fungal connections is then fed a high phosphorus fertiliser.
Bandicoots love to eat these particularly nutritious fungi, and fungus spores are spread via their digestive systems, to the great benefit of the soil’s health. Any sturdy plant community has a “wood wide web” of these fungi. It’s good reason for encouraging bandicoots in our gardens.
Casuarinas are all excellent fuelwood trees, being amongst the hottest-burning woods in the world. They were much used by bakers in the early days of white settlement, so tend to have been eliminated from around all our little towns.
Belahs are capable of reaching a trunk diameter of 1m, but trees this size are rarely seen nowadays.
Our local she-oak species are:
River she-oak, Casuarina cunninghamiana;
Forest she-oak, Allocasuarina torulosa; and the
Belah, above.
Perhaps we can also include the bulloak, Allocasuarina luehmannii, as a “local” - though it rarely occurs on basalt soil, which is the topic of this blog. (Where we do see it on the basalt soil, there is always a strong admixture of sand.)
(For more on Casuarinas see my blog June 2008, and the article above.)

Friday, June 4, 2010

Butterflies Love Daisies

This photo does make the point!
The flower is the rare “Austral cornflower” Stemmacantha australe (also sometimes called the “native thistle, for obvious reasons - though it’s an inoffensive, non-prickly plant. Like the weedy introduced thistles, it is in the daisy family (Asteraceae).
The larger butterfly is the rather curiously named “pink grass-yellow” (Eurema herla), and this old lady has obviously seen better days.
She’s being rather pointedly ignored by an equally elderly pea-blue - possibly the long-tailed one (Lampides boeticus).
They may not have laid their eggs in my garden, but if they have, the yellow butterfly would have chosen a Senna, while the blue would have chosen something in the pea family - perhaps the Crotalarias which attract so many little blue butterflies to our garden.
Use the search box at top left for another posting on the Stemmacantha, or search for Asteraceae, the daisy family, for some other butterfly-attracting daisies. The search box will also find more information on a local Crotalaria, or on local Senna species. 
All three kinds of plants are very good for attracting butterflies to our local gardens


Polyscias elegans
This picture was taken at Rockmount two weeks ago. The whole tree was a mass of fruits, and must have been a picture in spring, when it was covered with little purple flowers.

The (distinctively flat) celerywood fruits are adored by our local native fruit-eating birds, such as satin bowerbirds.

The trees themselves are very good value in a garden. Although they have a very lush, green, “rainforesty” look they are really very tough survivors. Even young seedlings thrive through droughts, and the also survive frosts so long as they have a bit of shelter from the worst of them.

These plants are growing on a high, exposed site, in a cow paddock on the western side of Mt Kynoch.

Celerywood seedlings couldn’t possibly have established themselves in this kind of environment. The kikuyu, the cows, and the harsh, windblown western exposure would now make it impossible. So these trees must have begun life in a kinder habitat, and are now evidence of a lost ecosystem, part of the extensive area of dry rainforest which must once have been common around Toowoomba.
Celerywoods are very fast-growing - one of our fastest trees - and like so many dry rainforest plants, they prefer to begin life in the shelter of trees and shrubs, but reach rapidly for the canopy to spread their leaves in the sun.

This one has been in the ground at Peacehaven Botanic park (Highfields) for two years, and has had no water since it was first planted. You can see from the slightly yellowed leaves that it would be happier with other plants around it, but it will get over this, and no doubt make a shapely tree in a short time.

Here is an example of the more typical young growth form. This sheltered specimen at Ravensbourne National Park is making a very fast bolt for a high place with good view of the sky.

This tendency grow tall and thin, together with an inoffensive root system, makes celerywoods suitable for use between buildings.

Old, rainforest-grown trees can have a trunk diameter of 75cm, but it is rare to see such a magnificent specimen nowadays, as they were cut for their soft timber which was used to make disposable items like fruit-cases (These were once as common as cardboard boxes are now. We used to break them up for kindling to use in fireplaces and wood stoves) .
Timber-getters used to identify them by the faint celery odour of the fresh bark. (The leaves have a stronger smell).