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Short items of interest about Australian plants selected from the many newsletters and journals published by member Societies of ASGAP.......
Short Cuts in this issue:
- Bartle Frere Oak - Eidothea zoexylocarya
- From an ancient relic in Victoria to a living tree in North Queensland.
- The Pricelessness of Kangaroo Grass
- Native grasses form an important component of
a balanced ecosystem.
- Koalas and Eucalypts
- We all know that koalas eat eucalypt leaves....but what species???
- Eremophila Seed Trials
- Trials of smoke treatment produce some positive results.
- How Not to Grow Eucalyptus caesia
- Tips from an almost expert!!!
- Fertilising Australian Native Plants
- What fertiliser? How much?? Should you apply fertiliser at all???.
Bartle Frere Oak - Eidothea zoexylocarya
On the misty slopes of Queensland's tallest mountain is a plant with history dating back millions of years. Greg Calvert takes up the story....
High in the National Park, on the misty western slopes of Queensland's tallest mountain, Mt Bartle Frere, botanists have recently discovered a plant which is being hailed as one of the most significant botanical discoveries this century.
The family Proteaceae has often been regarded as amongst the most primitive of flowering plant families in the world and contains such archaic species as the tree waratah (Alloxylon flammeum), Queensland nut (Macadamia integrifolia) and wheel-of-fire (Stenocarpus sinuatus) as well as the better known grevilleas, banksias and proteas (from South Africa). Proteaceae plants appear in the fossil record before the extinction of the dinosaurs and would certainly have been eaten by herbivorous dinosaurs.
The history of the discovery of the Bartle Frere oak extends back to 1875 when the famous botanist Baron Ferdinand von Mueller acquired a fossilised seed found near Ballarat in Victoria. Described as a 'grand fruit of a long bygone age', Mueller carefully drew and recorded the unusual fossil.
Eighty-six years later, CSIRO botanist Dr Bernie Hyland found some unusual seeds on Mt Bartle Frere and, not knowing what they were, sat them on his desk, where they sat for the next 20 years. In 1994, Dr Hyland finally discovered the parent tree and sent seed to an American expert on Proteaceae who established the link with Mueller's fossil.
This tree apparently flourished in Victoria between 50-65 million years ago at the time when Australia and Antarctica were still joined and Antarctic beech (Nothofagus) formed huge temperate forests. The cool moist western slopes of Mt Bartle Frere provided the last refuge for this amazing living fossil. Previously known as "Proteaceae sp Mt Bartle Frere", it has now been officially named as Eidothea zoexylocarya and is the sole representative of a newly described subfamily of Proteaceae.
Eidothea is a reasonably large canopy tree which is to all intents and purposes completely indistinguishable from the surrounding vegetation. Unlike other Proteaceae which have large spectacular lobed leaves, the leaves of Eidothea are simple with smooth margins. The trunk and bark are nondescript although you know you have found the right tree when you see that numerous botanists have blazed the trunk to reveal the distinctive silky oak grain characteristic of all members of the family.
The best way to locate Eidothea is to look for the fallen seeds on the ground. Encased in a green leathery rind similar to Macadamia, the nut itself is hard woody and pitted with numerous small indentations and squiggles. The nut is quite tough and thick when ripe though soft and pliable when green.
As the fruit ripens, numerous walls grow out into the liquid endosperm contained inside (reminding me of a coconut). Although I thought I had discovered something unique here, it is apparently known from other Proteaceae. The walls or lobes grow into the nutritive tissue and function to absorb the nutrients for the benefit of the embryo.
|Photo: Greg Calbvert
Once the food value of the liquid has been depleted then the role of the lobes is complete and the seed is mature. If you've never seen anything like this before, it is quite bizarre. I would like to open other immature Proteaceae seeds to compare their development with this arrangement.
Finding an intact seed on the forest floor isn't only difficult, I would hazard a guess that it is damn near impossible since the White-tailed Rats and Bush Rats tear open the seeds with great relish to consume the seed inside. I doubt they are edible to humans since freshly opened fruit smell strongly of bitter almonds indicating prussic acid (hydrogen cyanide). Many animal species are capable of detoxifying dangerous poisons such as this which would prove fatal to humans if ingested in large quantities.
How Eidothea is able to reproduce under such heavy pressure from seed predators is quite beyond me. A few years ago I assisted in an experiment to see how well rats could find the seed of the Atherton oak (Athertonia diversifolia). Every seed we buried was dug up overnight by the rats regardless of how well we buried them. Some must escape to produce the next generation, yet out of several hundred we tried to hide, not one escaped.
Although Eidothea is extremely limited in range, it is nonetheless fairly common at its preferred elevation and seems to be secure regardless of rat predation. It would be interesting to know what seedlings and saplings looked like so it would be possible to see how many young plants were being recruited into the population.
The Bartle Frere oak is an amazing and ancient relic with an amazing life history. Uncovering the secret of this and other plant species on the cold misty slopes of Mt Bartle Frere would be a lifetime job.
Now I'm sure I saw a a Nothofagus there somewhere...........
From "The Native Gardener", newsletter of the SGAP Townsville branch, June/July 1998.
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The Pricelessness of Kangaroo Grass
It's only relatively recently that the importance of native grasslands has started to be appreciated. Re-establishing what has been lost is not easy, as Lyn Hovey explains.
Kangaroo Grass (Themeda triandra) was once the most commonly found native grass on the Western Plains (Victoria) but more than 99.5% of the resource has been destroyed.
In January a field day attracted more than 50 land owners and interested people to the Organ Pipe National Park to see demonstrations of equipment for harvesting kangaroo grass and to hear advice about native pasture management. The Trust for Nature regional co-ordinator, Shelagh Curmi, who organised the day, highlighted the current and potential economic values in a bid to win support for grassland conservation. She said, "Very soon land holders with native grasslands will be the envy of their neighbours who, faced with increasing costs of weed control and other land degradation problems, will rue the day they destroyed theirs".
Anyone who has tried to revegetate an area with kangaroo grass will know it is not a simple matter. Kangaroo grass is a summer growing plant and it needs the right conjunction of many factors including a correct assessment of ripened seed, ground temperature. the right levels of moisture and weed control. Danthonia spp (Wallaby grasses) however, can be spread easily by group planting up-wind and sown as a winter growing grass at a time when you would expect moisture.
The Themeda triandra 'hay method' involves the collecting of kangaroo grass hay, spreading it on the ground, burning in Autumn and waiting for germination in spring. This method was pioneered by Keith McDougal and has been used successfully at the Organ Pipes National Park for many years.
Some native plant nurseries grow kangaroo grass in cells for large scale projects.
- Western Plains Flora (03 5428 2738) is a wholesale native plant nursery and grows tubes and cells for Landcare projects, road revegetation and landscaping.
- Bushland Flora at Mt Evelyn (03 9736 4364) will grow cells to order and supplies tubestock at 85c per tube if you are buying more than l00.
- Alliance Seeds (or Alliance Revegetation) at The Basin (03 9761 0906) supplies kangaroo grass seed. It varies in price according to quality. It costs $500 - $550 a kilogram for pure (cleaned) seed and florets can be bought for about $300 per kg. One kilogram of florets cleaned. goes back to 5% of seed. They have developed a machine to harvest Microlaena, Danthonia, Themeda and Redleg grass from native grasslands in broad acreage. Small areas are usually hand harvested and seed can be professionally cleaned making it a very labour intensive and expensive business.
- Nindethana Seed Service in southern Western Australia sells pure seed and a rough seeding grade costing $105 per kg mainly to mining companies to revegetate.
At present seed is in demand in the nursery and landscape business but as yet no-one has been able to establish large scale 'crops'. Best to save the remnants we've got.
From the Keilor Plains Group newsletter, May 2000 via "Growing Australian, June 2000.
Themeda triandra - illustration by Fred Duncan.
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Koalas and Eucalypts
Koalas eat the leaves of only about 35 of the more than 750+ eucalypt species. Kathleen Davies has been observing the habits of this Australian icon.
Koalas (Phascolarctos cinereus) family Phascolarctidae, are one of Australia's best known animals.
The distribution range of Koalas is from eastern Australia including much of New South Wales, Queensland and Victoria, and parts of Western Australia, South Australia and including Kangaroo Island. They are not overly common in any of their range and there are variations in size and depth of fur covering depending on environmental conditions.
They are a highly prized visitor to any backyard or garden, but it is unlikely that they would stay around more than a few days, unless you are fortunate enough to live on a large property with a Koala colony resident nearby. Koalas need large amounts of foliage from very particular eucalypt trees. They may, as in our case, visit young saplings of suitable trees to sample the wares and also during mating season when movement is common among male Koalas in search of female partners.
Dogs frequently attack Koalas that are on the ground. Koalas only leave the safety of trees when travelling in search of food or a mate.This is when they are most vulnerable to dog attack.
They are nocturnal animals and if seen during the day are usually curled up in a ball in the fork of a tree or slowly nibbling on some leaves.
Mating calls from Koalas are often a scary sound to the uninitiated, especially at night. The crescendo of grunting and squealing sounds something like a mob of wild pigs!
Koalas are wild animals, not cuddly pets, and they have the ability to bite and scratch causing severe injuries to the unwary.
The trees listed below are a general selection of different eucalypt species that provide a food source for Koalas. Plant nurseries should be able to supply at least a few of the species, State Forestry nurseries may have a larger range. If Koalas are not noted to be in your area to start with, it is highly unlikely that you will be able to attract them to your property.
Suggested species of eucalypts
Further research will provide the observer with several more species to add to this list, and you may also note the species native to your area will be best suited.
As well as the listed known food trees for Koalas, I have observed them eating, or perhaps taste testing, species such as the imported radiata pine, Paperbark (Melaleuca quinquinervia) and Casuarina (Casuarina sp.).
Koalas are not very active, so you could be sitting watching them for many hours before seeing even a minor movement such as the turning of a head or the shifting of the rump to a more comfortable position in the fork of the tree. Spotlighting at night provides viewing of more activity (although only slightly), but remember to hold a strong spotlight beam on an animal for only a few seconds at a time as the strong light can damage their eyes and disorient them. Strong beams at very close range can also become very hot and cause burns.
From the newsletter of the Wildlife and Native Plants Study Group, Autumn/Winter 1999.
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Eremophila Seed Trials
Russell Wait describes trials using smoke treatment of Eremophila seeds. The results suggest possible benefits from this approach.
Before I sow the seeds I check them to see if they are viable - I usually take four plump drupes and cut them open and look for the plump, white seeds. The best way to open the drupes is to split them from the bottom along the division, and then into quarters, then I look for the seeds. There can be twelve or so seeds in the drupes of some species. Some species with smaller drupes have to be cut crossways to the way the seed lies so that viable seeds can be found; unfortunately some of the seed is destroyed by this later process. Even if I find no viable seed in the drupes I still sow the drupes. I found no viable seed in some Eremophila pantonii however, two seedlings came up in November from fruits sown in September.
Last year (1999) in March I sowed more seed and used smoke water, but I sowed the seed out in the plantation, and not in propagation boxes. The reason for doing this was that I have so many boxes holding seed in the propagation area awaiting germination, that I am running out of room.
The soil in the plantation is sandy loam over a clay sub-soil. I made up two plots the same, banking soil around the perimeter - this being done to allow me to flood irrigate the plots.
The seed was checked for viability and then sown into dry soil, this was followed by a watering of 30 litres of water plus 0.5 litres of smoke water in one plot and 30 litres of water only in the second plot. Twelve hours later both plots were watered to a depth of 2cm and covered with 75% shade cloth, and similarly watered a further twice on that same day. The next day each plot was flooded with 2cm of water in the morning and again the second night. Each plot was again watered once only on the following day. After that the plots were watered as I thought they needed it. The shade cloth was left on for five days, when some succulents began to appear in each plot - no doubt from seed naturally present in the soil.
The following results were obtained (as at 16.06.99):
E.polyclada x divaricata
E.polyclada x bignoniiflora No.1
E.polyclada x bignoniiflora No.2
E.spec. nov. (95262-6)
I have managed to get germination of the following species by using the smoke water treatment, however, the percentage germination has not been very high.
E.glabra, E.granitica, E.denticulata, E.maculata, E.youngii, E.virens and E.nivea.
It seems as if E.racemosa, E.maculata, E.drummondii and E.pantonii prefer to germinate in the spring, the others in the autumn I have one problem with autumn grown seedlings of Eremophila and that is frost and overwintering them. I have also found most need to have some size before they are planted out into the plantation after germinating in the propagation area. Two April frosts this year killed one E.cuneifolia and affected a couple of others.
Eremophila bignoniflora (left) and Eremophila youngii (right) showed some beneficial reaction to smoke treatment.
Select the thumbnail image or plant names for higher resolution images (33k and 32k).
Photos: Keith Townsend and Brian Walters
Of further interest, I left the hose dripping for three days at the base of a plant of E.hygrophana and forgot to turn it off. The result was about forty seedlings. There were a lot of drupes on the ground when I came to dig the seedlings up and I had to cut five before I found one with a viable seed in it. It looks as if there is going to be a variation in the seedlings, as some have goldish tips to the leaves and others grey. Also I found one seedling each of E.maculata and E.Iongifolia at the base of the same plant.
Last year I planted most of my plants out in the plantation in late September, using a dripper system for watering and most have responded well with good growth.
In summary, my thoughts on the use of smoke water are that the drupes should be kept wet for the first three or four days and that they should be sown in late summer, this also applies if no smoke is used. Results so far suggest that smoke treatment is effective for many species.
From the newsletter of the Eremophila Study Group, August 1999.
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How Not to Grow Eucalyptus caesia
In eastern Australia, Eucalyptus caesia remains a "hit or miss" proposition. Lloyd Hedges, it seems, has had his fair share of "misses"!!!
There are very few things in life I can claim any expertise in, but the headline subject is one of them.
The number of healthy, happy E.caesia I have purchased from this or that nursery and watched slowly wither and die in my garden must be in the dozens. If there is a "Crimes Against E.caesia's" Tribunal then I have very little doubt I will be at the head of their hit list. It may just be my inherent paranoia, but whenever I walk near the E.caesia section in a nursery I seem to hear whimpering and see leaves shivering in fear as the plants try to blend into the background or pretend they are something else altogether. Of all the specimens I have purchased, only one survives, as a pot plant that is at present in flower, hence the reason for this missive.
For those that have yet to come across this plant, the sub-species, magna, which is the one usually sold under the name "Silver Princess", is a small, weeping, grey foliaged tree and the new stems and the large capsules are covered with a silvery bloom. The capsule doffs its silver cap to reveal a large flower with pink-red, gold-tipped stamens. Never has the common name been more appropriate. A truly stunning plant!
The large, pendulous flowers of Eucalyptus caesia create an eyecatching diisplay.
Select the thumbnail image or highlighted name for a higher resolution image (33k).
The books tell me that the E.caesia is native to the central wheat belt region of Western Australia, where it is usually described as growing among the boulders at the foot of granite outcrops or cliffs, so the plant enjoys a natural climate of low rainfall (200-400mm) almost all of which falls during the winter months. This would explain why it falls victim to fungus diseases of the leaves in Sydney's warm moist summers although, interestingly enough, it doesn't seem to suffer from the root fungus diseases that afflict so many of the other Western Australian plants, particularly the Proteacae. (If you do buy a western Banksia or similar on its own roots, I suggest you take a camera with you when you plant it, as by the time you have returned from a well-earned cup of tea it will most likely be dead!).
Back to the E.caesia.....
Armed with this book knowledge, my not inconsiderable experience of failure and a penchant for stopping and examining every successful plant I see, I would like to offer the following suggestions on how NOT to NOT grow a E.caesia.
- Only buy a healthy plant with no marks on its leaves.
- Do not water vigorously or over the foliage as this encourages fungal growth and splashes fungal spores up on to the leaves.
- Plant in an open, sunny, airy position that will not allow rain or dew to drip off other plants on to it.
- Preferably plant in a rockery or where it can get its feet under rocks or a concrete driveway or similar. In sandy soil, they are prone to blow over.
- "Mancozeb" can control the leaf spots, but it is not a long term solution. If the plant is not in a suitable spot, spraying only delays the inevitable.
If you are successful in growing this lovely little tree you will be rewarded by visits from all sorts of desirable wildlife that wish to sample its nectar.
From the newsletter of the Menai Wildflower Group, June 1997
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Fertilising Australian Native Plants
There is more folklore about the effect of fertilising on Australian plants than for almost any other subject. It's not all black magic, as Kevin Handreck reports.....
Q. Should I use fertiliser when planting out Australian native plants, and if so, what fertiliser and how much?
A. Yes or no: take your pick!
The answer to this often-asked question depends on what and where you are wanting to plant. It has long been said that Australian plants should not receive fertiliser at planting: they should be left to find their own nutrients; they should not be stimulated to excessive growth.
Yet it is common practice when establishing eucalypt plantations to apply nitrogen and phosphorus at planting. When a eucalypt plantation is being established in an area of high rainfall (say over 550 mm per year), it would be usual to apply some fertiliser. For soils with a low organic matter content in high-rainfall areas, the amount per tree is the equivalent of about 25 grams of urea and 70 grams of single superphosphate. Lower amounts would be used when planting into farmland. These additions of nitrogen and phosphorus replace the abundant supplies of these nutrients that young eucalypt seedlings would find if they were establishing themselves in an ashbed. But with farmland soils, it is also often necessary to apply trace elements such as copper and zinc to balance the amount of other nutrients that are available to the young eucalypts.
But what about other Australian plants in other situations? I suggest that the correct answer depends very much on the condition of the plant at planting, plant type, soil fertility and water supply.
An Australian plant that has been so starved that most of its leaves have dropped off and the remaining ones are purple, will have little ability to produce new roots after planting out. If it does not encounter some nutrients soon after planting it may die. Such a plant is likely to respond positively to some extra nutrients in the bottom of the planting hole when it is being planted into soil of low fertility. On the other hand, if this same plant were to be planted into a fairly rich garden soil, it would soon start taking up nutrients and so would not need more.
A plant that has grown well, and has been hardened off through some restriction in the amount of nutrients being provided to it, is unlikely to need any further nutrients than would be provided by most garden soils and farmland soils that have received fertilisers over the years. But if it were to be planted into a sandy soil that has received little fertiliser, it could benefit from a small fertiliser application. A suitable application would be a level teaspoon of controlled-release fertiliser (Nutricote or Osmocote) in the planting hole.
But on the other hand, if the environment in which the plant is being planted has a low rainfall (less than 400 mm), and there is no possibility of providing any water above that of rain, it could be that the extra growth stimulated by the fertiliser could produce shoot growth that is too large for the root system. In this situation, the extra fertiliser may well lead to death of the plant during its first summer, because its 'plumbing' has not been produced in proportion to shoot growth. In such environments, the plant should be allowed to find its own level of growth, which will then be in tune with local rainfall.
If the plant is being planted into a new garden whose soil is of low fertility, it would be appropriate to apply fertiliser as the growth allowed by that fertiliser will be able to be supported by typical garden irrigation.
Of course you would not apply any phosphatic fertiliser to phosphorus-sensitive plants (except for a small amount in the form of a controlled-release fertiliser if you are planting into sand that contains essentially no organic matter).
From the journal of the South Australian Region of the Australian Plants Society, May 1997.
At the time this article was written, Kevin Handreck was Senior Research Chemist with the CSIRO (Commonwealth Scientific and Industrial Research Organisation) Division of Soils, Adelaide. For further information on phosphorus sensitive plants refer to Kevin's article Phosphorus Needs of Some Australian Plants.
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Australian Plants online - September 2000
Association of Societies for Growing Australian Plants