Friday, 28 August 2009

The Rastafarian Palm from New Caledonia

Quite a few of our palms are in flower or fruit at the moment. If you take the walk behind the Tropical Centre you'll see just a few of our extensive palm collection - in total some 2000 individuals representing 140 different kinds of palm.

If you arrive from the Morshead Fountain Gate opposite the State Library, one of the more curious flowering structures can be found in a group of three palms just at the fork in the path that leads one way towards the Pyramid and the other around the Expressway side of the route around the Arc.

These palms are called Burretiokentia hapala. Their flowers are borne on velvety tentacles or fingers that protrude out from the stem of the palm. The look and texture of this inflorescence is hard to describe but in the pictures above, taken by Simon Goodwin, you see they are a little spider- or octopus-like, perhaps like the hairdo of The Simpson's Sideshow Bob, or more closely, Rastafarian dreadlocks.

The palm is know only from forests in northern New Caledonia, where it is listed as a species 'vulnerable' to extinction, although it flourishes locally after selective logging. Fire and the trampling of seedlings by hunters and climbers are the biggest threat to its survival.

There are 37 species of palm in New Caledonia, but that number is expected to at least double once the results of current taxonomic research are published (Burretiokentia hapala was only discovered in 1964). As with the palms on Lord Howe Island, every one of these species grows here and no where else.

Palms are just part of the botanical appeal of New Caledonia. It's chock full of fascinating plants, many with evolutionary links to the Australian flora. The country is about three-quarters the area of the Sydney region, but supports at least 3,500 species of vascular plants (flowering plants, conifers, ferns etc.). Around Sydney we have about 2,000 species of vascular plants and we quite rightly recognize it as one of the great wildflower regions in Australia!

Like Australia, New Caledonia has 80% of its species that occur no where else in the world.
New Caledonia separated from Australia 65 million years ago (part of the Gondwanic split), and many of the plant groups are related to those of Australia, but with different species.

Again like on Lord Howe Island, this palm species doesn't have any close Australian relatives. However unlike the Kentia Palm from Lord Howe, New Caledonian palms are generally not easy to grow, and the collections in the Royal Botanic Gardens in Sydney are important for conservation and science.

Tuesday, 25 August 2009

Five seasons, and over and out

As media interest in changing our seasons starts to wane at last, perhaps as we move closer to ye olde 'spring' - or at least the day where Australian's tend to start spring - I present this lovely diagramatic illustration of a possible Five Seasons system for coastal Sydney, thanks to Karen Rinkel, one of our talented Graphic Designers at the Botanic Gardens.

Over the last two weeks, there have been more than 30 media articles and broadcasts – 4 newspaper, over 25 radio, 4 TV and 3 web. Interest spread out around all states in Australia and then internationally (BBC Worldservice, UK and Scotland, and two NZ radio stations).
Responses have varied but mostly people have enjoyed the chance to question our four-season system, and to think about the big biological and climatic changes in each year. It's clear that Indigenous communities have over tens of thousands of years come up with systems far more meaningful than our imported European schema. We could adopt these rather than my slightly plant biased system, or at least use local Indigenous names instead of my clumsy 'springer' and 'sprummer'!

Either way it would mean different seasons for different parts of the country but if that's the way it is, that's the way it is. Our calendar and clock (daylight saving differences excepted) are for keeping us all organised - seasons could be for tracking the changes in the environment around us. And do we change seasons as the climate changes? Perhaps. Maybe that's a good thing too.

Lots of questions and little resolution, yet. But it's a start...

Sunday, 23 August 2009

Open Gardens, and Science

Firstly the launch of the 2009-2010 Australia's Open Garden Scheme at 'Yarrawa', in Burrawang, about an hour and a half south of Sydney. Dr Holly Kerr Forsyth spoke eruditely about the history of gardening, the beauty of Bruce Rosenberg's Yarrawa (a garden that features in Kerr Forsyth's most recent publication, Gardens of Eden: Among the World's Most Beautiful Gardens) and, simply, the 'need for gardeners to garden'.

The event was hosted, as always, and wonderfully, by the erasible Andrew Buchanan. The garden of Yarrawa was very pretty and beautifully designed. My pictures below show just some of the many helibores - after four days of trimming to remove dead leaves apparently - and the patch of restored Yarrawa Brush at the entrance to the property. The garden is only 15 years old. It began as a bare paddock with a few (magnificent and large) Brown Barrels (Eucalyptus fastigata).

For information on the Open Garden Scheme, and a copy of the 2009-2010 Guide click here. For a few pictures of Yarrawa, see here...

From Burrawang, to Woccanmagully (or Wogganmagule). Here, in what is also called the Royal Botanic Gardens, in Sydney, our science was 'open' for the day. Talks, tours, games, displays and Rotary BBQ'd sausages, as well as scientists at work - sorting seeds, examining plants under the microscope, preparing herbarium specimens and illustrating.
Here are a few pictures of the day... You can see Steve Paul and Kathy Pfleger (Community Greening), Lesley Elkan (Illustrating), Amelia Martyn (seed sorting) and Karen Wilson (looking at a spring wattle under the microscope).

Thursday, 20 August 2009

TV Spring at Night

I've just had the disconcerting experience of being interviewed for TV in the middle of the Royal Botanic Gardens lit up like a spotlighted rabbit, with an earphone in my slightly deaf ear (the right one) and the 7-second delay on my voice feeding back into the same earphone.

I could hear the questions, just, and miscellaneous night noices and what I took to be some audience participation (i.e. I think they laughed occasionally). So I said my piece, about the need for an early spring and an extra season, and with relief my goodbyes when we seemed to have reached the end of the questions.

Odd and not very pleasant. Depressed, I made my way home determined to never do a TV interview at night, put the earphone in my left ear the next time, and try and work out a way to stare down the camera at the same time as remembering all those witty things I was going to say.

My family very kindly taped it for me, so with some trepidation I thought I should watch it so I could improve for next time. Ah, the magic of television. Somehow, and I don't know how, it actually looked and sounded like I knew what was going on and was in some kind of control. Amazing.

If you are not a regular watcher of the '7 PM Project' on Channel 10, you have the opportunity to review my performance on the web (it might not be up yet, but perhaps in the morning). Just remember that I'm still recovering from the experience...

For a slightly more coherent line of argument, see the ABC Online report. For some sometimes very passionate responses to my ideas, read the comments below. It's funny how this topic divides people into two main groups: the first want to know why I don't have something better to do with my time, the second have been thinking much the same thing but usually with slight adjustments.
I think it's a fascinating topic and quite pertinent to how we observe and respond the world around us. But then you know that.

Wednesday, 19 August 2009

Sea Change (P4P*)

The kind of plant we might display in the botanic gardens later this century? (It's a picture I've used before but too good to resist for this story.)

The land seaward of the Gardens Restaurant in the Royal Botanic Gardens was reclaimed from the sea over a period of 30 years in the mid nineteenth century. In the next 30 years some of it could well be claimed back.

Modelling by the Department of Environment and Climate Change, our parent Department, predicts a 40 cm rise (above 1990 levels) by 2050, and a further 50 cm by 2100. So we’d expect the harbour to be nearly a foot higher in 30 years time.

Our Seawall should cope with this kind of sea level rise, although king tides are likely to reach further into the Royal Botanic Gardens. Already they dump seaweeds on the paths, and occasionally fish and other marine life, but these all arrive through the deliberately cut slots in the wall.

Even centimetre rises will increase the likelihood of flooding, and of the soil becoming even more saline. The bottom lake in the Royal Botanic Gardens has always been brackish and water flows back and forth from Farm Cove, depending on the sea level.

Mullet and long-finned eels also travel through this channel between Farm Cove and the pond, although the eels can do it overland on a rainy night (in fact the mature eels have to leave the pond to spawn, migrating all the way to New Caledonia).

Accelerated climate change in the Sydney region is also likely to increase minimum and maximum temperatures by up to a couple of degrees. Summer rainfall on the coast is likely to increase (but not necessarily in the catchments), but winter rainfall is more likely to decrease.

These changes to the climate will eventually affect what we can grow in the Royal Botanic Gardens. Some plants can tolerate wide variations in temperature and water availability, while those grown at the extreme of their range may succumb. Because we display many different plants, from all around the world, some will much harder to keep alive.

If we have more, or more severe, storms and winds, that will obviously affect how we care for existing trees and the kind of trees we plant over coming years.

So what can we do? Already, when we replaced the stone wall around our two islands in the Main Pond recently, we took the opportunity to make then 50 cm higher. In our reviewing our ‘thematic plans’ (our guides to what grows where and why), we’ll take into account likely changes in salinity along Farm Cove and perhaps require that all new trees planted in the lower garden are in raised beds or mounds. In any repairs and maintenance to the sea wall we’ll take into account likely sea level increases and the increased threat of storm and tidal damage.

In Sydney generally, our gardens will change. You should look at the effects of the 40+ degree day in coastal Sydney on New Year’s Day in 2006. Tree ferns growing out in the open may be a thing of the past, as might be box hedges in planter boxes. Consider bromeliads, succulents or local native plants, but also water-loving gardens in seepage areas and near your rainwater tank.

On the positive side, our gardens have already adapted a little due to the new watering regime (recently relaxed so we can water every day, early in the morning and later in the afternoon). Although most gardeners would prefer some more flexibility in the system, most of us probably over watered our gardens in the past. We’ve all lost a few plants but we are planting and preparing more wisely now. Even though we may get more summer rain, other seasons could be quite dry and the higher temperatures will lead to more evaporation.

Meanwhile, do all you can to reduce your carbon footprint and you may save, among other things, the Royal Botanic Gardens.

*This Passion for Plants posting will also appear on the ABC Sydney website (possibly under 'gardening'), and is the gist of my radio interview with Simon Marnie on Saturday Morning sometime between 9-10 am on 702AM.

Monday, 17 August 2009

Flowering, For the Very First Time

It has been pointed out to me that eucalypts haven’t yet featured in my blog. It’s appropriate for me to feature this genus today, because a visitor to my office this afternoon described the genus as our one of our worst weeds.

So today I feature a species that has a long way to go before it becomes a weed. In fact there are only three individual plants remaining in its natural habitat in the Blue Mountains. Three! Remember Wollemi Pines number just under 100 mature trees in their remote canyon north of Sydney.

The suggestively named Eucalyptus copulans was discovered at Wentworth Falls over a hundred years ago but only named as a distinct species in 1991, by former Director of the Trust Lawrie Johnson and former Trust scientist Ken Hill. At that time it was thought to be extinct and the species name refers not to its virulence, but to this species ‘joining’ or being intermediate between two others.

Since the three surviving trees were discovered, 1000 or so seeds have been collected and deposited in the NSW Seedbank at Mount Annan Botanic Garden. We’ve grown on some of this seed and planted specimens in our botanic gardens.

In November 2003, Professor Peter Crane, Director of Royal Botanic Gardens Kew, and the Hon Bob Debus MP, NSW Minister for the Environment, planted a Eucalyptus copulans in the Rare and Threatened Plant garden just outside the entrance to the Maiden Theatre. They also planted a specimen of the rare Nightcap Oak (Eidothea hardeniana) from north-eastern NSW.

Both plantings were part of the official launch of ‘Seedquest NSW’, a partnership between the NSW Seedbank and the Millenium Seedbank UK to conserve 10% of the world’s flowering plants in our seed banks by 2010 (we are almost there, and the target will be met).

Today, nearly six years on, our 5 m tall specimen is bearing its first flower buds. They are only a few mm long but they signify big things – the successful conservation of this species, albeit outside its natural habitat.

Image: photographs of the budding tree taken on the weekend by Simon Goodwin.

Sunday, 16 August 2009

Colour and movement

Contrary to some overseas perceptions, the Australian 'spring' is a colourful season. This mish-mash - and yes it really is a bit mished and mashed - gives a sense of the colour out in the Ku-ring-gai bush this morning, in mid-August. The pink flowers of the boronias were particularly intense.

Speaking of colour and seasons, but admittedly not of Australia and spring, why are autumn leaves more often red in America and yellow in Europe?

Fully functioning leaves are mostly green because they have more green chlorophyll (needed to process the sun's energy) than any other coloured pigment. In deciduous trees, the leaves change colour in autumn as the chlorophyll is recycled - either yellow as a default, or red if a new pigment, anthocyanin is produced. As I explained previously, anthocyanins may provide sun or pest protection, or both, or neither...

Researchers from the Universities of Haifa (Israel) and Kuopio (Finland) suggest we should look at evolution to see why there are more red autumn leaves in America than Europe. There study was published in the latest issue of the scientific journal New Phytologist.

They evoke a long evolutionary war between trees and the insects that use them as hosts. In autumn, insects such as aphids feed of leaves and lay their eggs. Aphids are attracted to yellow leaves so red leaves are a deterrent to this pest. But why do some leaves remain yellow?

Professors Lev-Yadun and Holopainen theorise that until 35 million years ago, much of earth was covered in evergreen tropical forest. A few ice ages and droughts led to the evolution of deciduousness as a way of coping through difficult times. It's proposed that the evolution of red autumn leaves, to ward of pests, also began during this time.

In North America, the trees and their insect pests migrated together along the long north-south mountain ranges as the climate changed. The evolutionary 'war' continued unabated.

In Europe the mountain ranges extend east-west and tree species that could not survive severe cold were more likely to die out, with their insect companions. At the end of the ice age cycle, many of the insect species were extinct and the surviving tree species has less need to spend energy on producing red leaves.

So the scientists hypothesise. Evidence for the theory includes dwarf shrubs that grow in Scandinavia which still produce red leaves. Smaller trees are more likely to survive ice ages becauase they can be protected from more extreme conditions under a layer of snow. The associated insects were also relatively snug and survived to fight another day.

As I said, all this has nothing to do with Australia or spring. My weak connection is that with accelerated climate change, it is important to have corridors for plants to relocate and to evolve. The beautiful bush at Ku-ring-gai is relatively extensive and has at least some connections to the north, although there isn't much mountain height (moving up and down is another way to cope with temperature changes).

And all this begs the question of why the sundew in the photo above is red. Obviously it doesn't repel the kind of insects it likes to digest. I suspect it's more to do with sun protection given the highly exposed places they live. Ah, evolution!

Friday, 14 August 2009

More Pictures of That Orchid....

Here are some more pictures of the orchid in the Port Jackson Fig, taken today. For more about the Bridal Veil Orchid see below. These pictures start with the tree, moving in towards the orchid plant and then its flowers.

I've also added at the end a picture of the climbing cactus, Queen of the Night (Hylocereus triangularis), identified by Simon Goodwin in the comment after my previous posting. As I noted there, and as befitting its common name, this is a plant you are unlikely to see in flower in the Royal Botanic Gardens - its flowers open at night and close by morning. Perhaps we need special summer viewing of this one, after hours.

And this is the cactus!

Wednesday, 12 August 2009

Best Orchid in the Botanic Gardens?

We have this fantastic Port Jackson Fig near our Palm House. It's a beautiful tree in its own right, but around and in it are a bunch of equally pretty plants. In flower right now is the Thin Pencil Orchid, also called the Rat's Tail Orchid and Bridal Veil Orchid.

If you look up into the tree you'll understand why it's called the bridal veil - the flowers are like a cloud of white stars. And if you are lucky a waft of the perfume may drift your way.

Botanically it's a species of Dendrobium or Dockrillia, depending on the taxonomy you chose to use. At the moment we have it filed away as Dendrobium teretifolia. It grows naturally from the tip of Cape York to south-eastern New South Wales - David Jones in A Complete Guide to Native Orchids of Australia illustrates the species with a picture taken in Penrith.

According to Jones, in New South Wales it grows almost exclusively on Swamp Oak (Casuarina glauca), a species that still grows naturally in the Royal Botanic Gardens. We think our surviving plants of Swamp Oak are suckers from a tree that once grew on the edge of Farm Cove, before the cove was reclaimed in the middle of the nineteenth century. Perhaps the orchid also once grew here naturally?

The same Port Jackson Fig is host to a climbing cactus, some kind of Epiphyllum species I presume, but I'll check with Simon Goodwin or Gareth Hambridge and add a comment later to confirm. Underneath there are a few hundred bromeliads, newly planted, and freshly blogged. I'm pretty sure the fig itself is planted, but Ficus rubiginosa a common local species, and does occur more or less naturally on the site.

Image: a picture of our Bridal Veil Orchid taken yesterday by horticulturalist Gareth Hambridge, who says this years blooming is particularly stunning. He also describes this specimen as the best orchid in our collection.

Tuesday, 11 August 2009

Newcastle Heralds Five Seasons

Firstly sorry to interstate ABC radio audiences who have had to endure my Sydney perspective on life, seasons and everything. This whole seasonal thing has become a popular topic.

I thought I'd share with you an article from the Newcastle Herald by Jeff Corbett. Jeff has similar ideas himself and has published on this a few times already. Today he summed up the sitation nicely in an article headed 'Spring to the Cause' (Newcastle Herald, 11 August 2009, p. 8). Jeff was happy for me to post his story, and would welcome further debate on his blog. And for more of my own thoughts on seasons click here.

Spring to the cause (by Jeff Corbett, Newcastle Herald, 11 August 2009)

"IT'S an indefinable something that produces an indefinable sensation, and it happened on Sunday. That was the arrival of spring.

Yes, I know spring does not happen until September 1, and that this date has been kicking off the Australian season of rebirth ever since the early 1800s when bureaucrats brought it forward from the spring equinox. They advanced spring by about three weeks so the overheating soldiers in the NSW Corps could swap their heavy winter uniform for the summer uniform earlier.

So not only have we been burdened by the unquestioned adoption of the northern hemisphere's four seasons, our spring, summer, autumn and winter were shuffled forward to meet the excesses of a military uniform designed for British winters.

We have modified laws, language, social structure and government to suit our own purposes, and one day we'll rid ourselves of British royalty, yet we accept the mother country's seasons without question.

Or you do. For a long time I have believed that I was Nigel No Friends in questioning, as longtime readers may recall, why we have just four official seasons, why they are of the same duration, why they begin when they do and why they should apply uniformly across a country of impossibly varied climate.

But I am Nigel Two Friends. On Saturday, I have just read, a guest speaker at a garden and market day in Pymble in Sydney outlined his case for five seasons, and that speaker was no less than the chief of Sydney's Royal Botanic Gardens, Tim Entwisle. And at Seaham the founder of Nature Watch and a retired lecturer in biological and environmental science, Kevin McDonald, agrees with him.

Dr Entwisle argues that the four seasons we have inherited from the northern hemisphere just don't fit our bill, and to illustrate this he points to the fact that the flush of flowering begins in and around Sydney in late July or early August. So he is proposing five seasons for the lowland coastal strip that extends north and south of Sydney and which includes Lake Macquarie, Newcastle, Port Stephens and, on a good day, Maitland.

According to Dr Entwisle's calendar, and my own indefinable sensations, we are now in spring, which occupies August and September. Yes, just two months, like four of the five seasons, because these seasons reflect segments of the natural cycle here on our coastal strip, not somewhere in the northern hemisphere.
Next is pre-summer, in October and November; then peak summer over four months, December, January, February and March; autumn in April and May; and winter in June and July. It does seem ludicrous that November is classified now as spring, that March is autumn.

Mr McDonald, who has been keeping daily records of his nature observations for many years, agrees with Dr Entwisle by and large. He points out that Aboriginal people had five, six or seven seasons that reflected the natural sequence in their region rather than another hemisphere.

Our region has six months of hot weather, Mr McDonald says, and that assessment fits neatly with Dr Entwisle's six months of pre-summer and peak summer. Mr McDonald co-ordinates a project, Nature Watch, that involves a loose group of people interested in observing the natural world ( if you're interested), and their records establish that while some things in nature are changing with changing temperatures, others that rely on daylight length are not.

Dr Entwisle has a fallback position. If we must stick with the other hemisphere's seasons he suggests we mark the start of critical periods in the botanical cycle, periods that will exist despite our unwillingness to recognise them as seasons.

Wattle Day on September 1 would have to be moved back to a date that more widely reflects the start of wattle's flowering, August 1, then we'd have Telopea Day on October 1, Hyacinth Orchid Day December 1, Banksia Day April 1, and Grevillea Day June 1.

We could do with more colour in our lives."

Image: 'Plant of the month' for August at our Mount Annan Botanic Garden. The wattle garden is spectacular at the moment, signally the start of spring.

Saturday, 8 August 2009

It's Spring!

Would these magnolias in the beautiful gardens of 'Claremont' in Pymble be flowering if it wasn't spring? Would the wattles be in full bloom across south-eastern Australia to the degree that the cabbie in Canberra tells me it must be spring, if it wasn't? What are the hardenbergias and boronias flaring purple in the bush for if it isn't spring?

Well there are a few responses to this of course. Firstly, perhaps, one wattle/magnolia/boronia does not a spring make. Then, there's plenty of other things not in flower. And on to, it's different for me because I live in Katoomba/Hobart/Darwin. And so on.

Of course 'seasons' vary across the country and the vary from year to year. But as I say every year, we don't have an early spring this year in Sydney, we have the usual start to our peak flowering season, in August.

So what to do about it? I've argued for a rewrite of our seasons - see specifically my suggested Seasons for Coastal Sydney or a few other mentions here.

Today I spoke on this topic at the Easy Care Gardening Garden & Market Day at the lovely 'Claremont' home in Pymble. I outlined my case for five seasons - spring (August, September), pre-summer (October, November), mid-summer (December, January, February, March), kind-of-autumn (April, May) and winter (June, July).

You've got to agree that it's appealing to have two months for winter and four for summer! But seriously, the seasons in most of our regions don't, and shouldn't, be the same as the old country. The trouble is that head just 100 km inland (and upland) from Sydney, my system won't work properly - for a start they have real autumns. And then there is the problem of temperatures and the like (climate) having cycles slightly different to the plants (which use day-length as well as water availability and temperature).

In any case I said today, as I've said before, that if we can't change the seasons let's at least celebrate the start of critical times in the botanical cycle. The first thing to do would be to move Wattle Day to 1 August rather than 1 September. I'm aware of the history of this day and that it was proclaimed nationally in 1992 to be 1 September, but...

I got some feedback today that Wattle Day is still celebrated (as it was more or less officially between the two World Wars) on 1 August in places like Orange.

It's a discussion we need to have. Before we can talk about changes in our gardens or the bush due to climate change, let's sort out our seasons or at least the recognition we give to the long-standing cycles that we live with every year.

Image: From the garden of 'Claremont'. For more about Easy Care Gardening see their website. Easy Care Gardening Inc. is a community based (not for profit) group assisting elderly and disabled pensioners to stay in their homes for longer. The support is through teams of volunteers weeding, mulching and pruning gardens. It's well worth supporting.

Friday, 7 August 2009

A Poetic Visit to the Macarthur Region

Today I inspired a poem after speaking to about 180 students in the Macarthur Region. Really.

The Macarthur Chronicle, the local paper of the Cambellton-Camden-Wollondilly area has set up what they call the Inspire Program to encourage young people in the region 'to follow their dreams'. The paper wants to address the negative stereotyping of kids in the area, exacerbated recently by publicity following the Rosemeadow riot.

Guest speakers are invited to visit secondary schools in the area, where they talk about how they got into their particular field and why its interesting. I was invited to speak today to year 10 and 11 students at the co-ed Broughton Anglican College at Menangle Park. It's partly about me imparting some inspiring words, and partly a chance for me to meet children from the school.

I talked about liking maths and science at High School, but also history and writing, and that typing was one of my favourite subjects in the first few years! It was tough dropping all but physics, chemistry and maths in Year 12, but in those days if you could do science you did science (and science only). Then into my well-worn story about starting university doing mostly maths and physics but switching entirely to botany in second year after being excited by a large picture of a plant cell (in the one small botany unit I did in first year).

From there I talked about getting hooked on algae and eventually botanic gardens. I showed some pictures of our three botanic gardens, with a particular focus on their local garden, Mount Annan Botanic Garden. They were intested in our plant for an Adventure Garden, a pump track and the enduro track (the latter two involve mountain bikes). I also mentioned the expanded Seedbank project, PlantBank. Finally a few of the more intriguing plants and plant stories, and a little about the kind of jobs we have at the Botanic Gardens Trust and what quals you need to get them.

Macarthur Chronicle will write up a story about the visit, but there's more. The biggest surprise, to me at least, was the reading of a poem written while I speaking. It was composed by staff member Charlie Dunn who regularly whips up a poetic response to talks and events. Perhaps it gives a more honest summary of what I said:

Ode to Entwisle

Doctor Entwisle, a scientist
Now director of Sydney garden is on his list.
He is in charge, he is the man
And now he’s visited Broughton Anglic - an

At botany he earned his degree
He studied microscopic, tiny algae.
A whole new algae he did discover
A whole new algae like no other.

Algae may to some be slime
Colours of brown to green and lime.
Some are good and some are bad
You can tell if pollution has made a creek sad.

1816 was the botanic garden’s birth
In a beautiful part of God’s great earth.
On Sydney Harbours edge
You can go to picnic, you can go to veg

Mount Annan, Mount Tomah, botanically new.
There is so much to see and do
Botany takes in from tree to thistle
We thank you for coming, Dr Tim Entwisle.

© C. Dunn
Friday, 7 August 2009

Image: One of the pictures I used in my talk, a paper daisy display at Mount Annan Botanic Garden photographed by Jaime Plaza.

Wednesday, 5 August 2009

Darwin's Descendents - The Exhibition

Charles and Emma Darwin had ten kids, but this exhibition isn’t about them, or his great-great-grandchildren. It’s about Charles’ scientific descendents – thousands of scientists working around the world on what I like to describe as the Great Adventure. Here are some notes from a speech I gave at the opening of the exhibition on Monday. What I can't provide is a transcript of Charles Darwin, in person, talking to four of our enthusiastic scientists...or Robyn Williams, both funny and smart, as always.

In short, Charles Darwin made sense of life on earth. Before Darwin, and Alfred Wallace, life was unexplained, and through this celebratory year (see plenty of postings below) I’m become more impressed by the man and his science, not less.

Natalie Angier in her book ‘The Cannon - The Beautiful Basics of Science’ – laments that we use the word Theory for his great discovery. In common parlance a theory is mere conjecture. In science, it’s about as close as we get to an indisputable fact.

What we do today is fine-tune the theory – just as we do with the Big Bang, Plate Tectonics, Climate Change….Capitalism?

Darwin spent most of his life experimenting, observing – before and after he published his theory. There was much more he wanted to check to resolve, he knew there were details to sort out.

One of those details was DNA. Another was to find more of the leaves on the tree of life (the variety of life on earth today) as well as the many more leafless branches – 99% of the tree – (the dead-ends, some of them preserved fossils).

What you can see around us today is the continuation of the great adventure started by Darwin. I know that when I dip my hand into freezing water in south-west Tasmania or the clear blue streams of Kakadu, I am entering a new world. When I return to the lab the discovery continues and each new collection adds to the story, the theory, the fact…

But my collecting has been pretty tame, except for a few crocodiles (which were mostly in my mind only). In our exhibition you’ll hear about head-butting a grey nurse shark, being covered from head to foot in ticks and parking the four-wheel drive on top of a critical specimen (haven’t we all done that, or discovered something new when relieving one’s self behind a tree…). Mind you, the exhibition doesn’t include the dangers of pipettes, or the reputed internet addiction (listen to recent episodes of Robyn William’s Science Show on Radio National).

Everyone in this exhibition is collecting, accumulating information, building up the picture. The scientists are finding new things, constructing new branches, fine-tuning the tree of life.

Perhaps 95% of fungi (150-250K, 5K described) are still to discovered, described and named; 20% of algae (12,000, 10,000 described); and 10-15% of green plants (21,000, 18,000 described), and some very serious trimming and grafting to do in all groups as we track down their DNA history.

In the exhibition we have three Trees of Life in the exhibition.

Firstly the original version drawn by Charles Darwin - which our PR Manager Kerry Brown describes as like a small piece of seaweed washed up on the beach

Then Ernst Haekel’s version drawn a decade later that looks more like a brown kelp growing on the sea floor, again thanks Kerry…

And thirdly a recent version by David Hillis (see image above) that could be a town plan for Canberra. Kerry points out humans are one shelf in one house in one street on the outskirts of that town. Try and find humans – you’ll need to use our magnifying glass if you look at the enlarged version of this ‘wheel of life’ in our exhibition. (Just one point of clarification though. About 3000 organisms are dotted around the edge of this tree/wheel and there is a disproportionate number from groups such as the green plants – the greatest diversity at higher taxonomic levels are in the protist and bacterial groups, the micro-organisms. Remember the quote I’ve used before: life to a first approximation is unicellular.)

And what does the real tree of life look like? More like the last, but more complicated still, with interconnections particularly back in the early years of algal evolution. And maybe there is another tree elsewhere in the universe, or as Paul Davies has pointed out, in some difficult to collect place on earth like a volcano or in the upper atmosphere. Now there will be some dangerous and interesting field trips, and a truly great adventure.

"Darwins Descendents: 200 years of scientific adventures", Monday 3 August – 24 November, Weekdays 10 am – 4pm. Red Box Gallery, National Herbarium of NSW, Mrs Macquaries Road, Sydney. Enquiries: 9231 8111. Entry is free.

Image: David M. Hillis, Derrick Zwickl, and Robin Gutell, University of Texas.

Sunday, 2 August 2009

Spitting Pollen

In the ‘isn’t nature amazing’ category, this plant has a clever and surprising trick to make sure it gets pollinated – it spits it on the visiting bee (or finger...).

Anneslea fragrans is not uncommon in the mountains of southern China through to Thailand, but you won’t see it in many gardens in Australia. It’s in the tea family, Theaceae, of which Camellia is the largest and most well know member. I was lucky enough to see a mature plant at Bob Cherry’s Paradise garden on Saturday, and to have its tricky pollination mechanism demonstrated to me.

You can see the pollen ‘spittle’ on Bob’s finger in the first picture above. The young flower has its petals tightly clasped together, forming something like a Russian church spire. The swollen part of the spire has slits in it to allow the perfume (it’s not called ‘fragrans’ for nothing) to escape, attracting pollinating insects such as the bee. You might be able to see the slits more clearly in this image.

So then the bee, or Bob’s finger, hovers around the fragrant bloom. If the tip of the spire – a protruding ‘style’ I think – is knocked in any way, a blob of pollen fires out the nozzle. The shocked and now pollen coated bee moves swiftly to a new bloom. This time it may be an older flower, fully opened and receptive to the smear of pollen that will be left on its style.

That seems to be the way it works. It’s fascinating to see the plant in action and we must get an Anneslea on display in the Royal Botanic Gardens (or at least I should find out if we have one at Mount Tomah).

Saturday, 1 August 2009

A Few Glimpses of Paradise

Today and tomorrow is open day at Bob Cherry's home garden 'Paradise'. I mentioned this garden in my posting about Derelie Cherry's beautiful new book 'Two Dogs and a Garden' but today I can provide a few pictures.

Bob Cherry showed us some of the gems in the collection, particularly Camellias from China and thereabouts. As always he would gather enthuisiasts as we swept (or more accurately, meandered) through the garden.

Here are a few more pictures from today, the first two Camellia amplexicaulis, a species we had in (single) flower a few weeks ago in the Royal Botanic Gardens.
And Bob in action...

More on Mr Darwin

I should have added to my last posting the link to more information about our Darwin calendar for the year - here!

The Science Open Day mentioned is more precisely 10 am to 4 pm on 23 August (i.e. not 23 and 24 August).

But first...starting on Monday, come look at what Darwin's scientific ancestors are doing in Sydney. See how they risk life and limb to collect plants, then grind them up to extract long 'sentences' such as TACGAATTCCGATGACAC... - sentences without punctuation and using only four letters, but the code of life.

Visit the Red Box Gallery, to your left after you cross the Cahill Expressway on Mrs Macquaries Road.

Darwin's Garden (P4P*)

In his later years, Charles Darwin experimented and observed nature in his backyard and glasshouse ‘laboratory’ at Down House in Downe, England. He studied pollination, climbing vines, insect-eating plants, and famously, earth worms, among other things.

His other ‘garden’ was the entire flora of the world, as observed and collected during the voyage of the The Beagle between 1831 and 1836. After the publication of The Origin of Species in 1859, this garden of creation became the garden of evolution.

This year we have been celebrating the 200th birthday of Charles Darwin and 150 years since the publication of his famous theory of evolution by natural selection.

One of the things we’ve tried to emphasise here at the botanic gardens – and you can see a reference to this in the quotes adorning our D-A-R-W-I-N installation – is Darwin's abiding interest in plants generally, and his particular love of animal-eating plants and orchids. (The picture above is the back of the letter ‘D’, featuring Darwin’s head!).

Darwin once said 'I care more about Drosera [the insect-eating sundews] than the origin of all the species in the world'. Perhaps a little hyperbole, but for someone who wasn’t all that taken by the Australian flora he fell in love with a genus of about 180 species, more than half of which are native to our country (mostly in south-western Australia). (Although he said he looked forward 'with more pleasure to seeing Sydney than to any other part of the voyage', he left saying famously 'I leave your shores without sorrow or regret’.)

He also said 'I never was more interested in any subject in my life than this of orchids'. Clearly he'd forgotten all about his sundews, but orchids certainly gave him lots of evidence for evolution and he published a major tome on how orchids and insects help each other, called The various contrivances by which orchids are fertilised by insects.

Those contrivances included trigger mechanism to bash the head of the insect against ready waiting pollen, buckets to trap the insect and direct it past the pollen, and long nectary spurs that require the insects to dip their head deep in the spur to get the sugary reward, thus....past the pollen again. Actually the pollen in orchids is glued together in a big lump called a 'pollinium', which can found attached to various appendages of your recently visiting insect.

Most famously, Darwin predicted the existence of a moth with a 30 cm long proboscis (straw-like device for sucking up nectar) after he saw an orchid from Madagascar with a 30 long nectar spur. 41 years later, and after his death, such a moth was discovered.

Here in the botanic garden you can walk along our Thinking Path, reading and contemplating the quotes about evolution. Every tree in the botanic garden can remind you of the tree of life, with the leaves representing species alive with us today.

It’s worth remembering, though, that most species are extinct, and most of life is unicellular. That is, to continue the analogy, most leaves have fallen off the tree and only a few of these leaves represent the flowering plants and largish animals we see around us every day.

And to learn more about Darwin and his legacy, visit the Darwin’s Descendants – 200 years of scientific adventure exhibition in the Red Box Gallery, on the left past the Art Gallery of NSW, from August 3 until November 24 (weekdays 10 am to 4 pm, free entry). There will also be Science Open Days at the Gardens on the weekend of 23 and 24 August 2009.

The back of the letter ‘D’, featuring Darwin’s head, and the first letter in the DARWIN installation at the Royal Botanic Gardens]

*This Passion for Plants posting will also appear on the ABC Sydney website (possibly under 'gardening'), and is the gist of my radio interview with Simon Marnie on Saturday Morning sometime between 9-10 am on 702AM.