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I've been a Canberran since moving here from Adelaide on the first day of 1980. I now live in suburban Duffy with my partner Louise Maher, ABC 666 radio and on-line journalist. Among my early memories is following Sleepy Lizards (Shinglebacks) around the paddocks north of Adelaide, guarded by the faithful bull terrier. I have always been passionate about the natural world, trying to understand how it works, how the nature of Australia came to be, and sharing those understandings. My especial passions are birds, orchids and mammals. I am now a full-time naturalist, running bush tours, writing books etc, doing consultancies, presenting a regular radio slot on local ABC, chairing a government environment advisory committee and running adult education classes. I was awarded the Australian Plants Society Award in 2001 and the Australian Natural History Medallion in 2006, both for services to education and conservation. As part of my fascination with our Gondwanan origins I've been running tours to South America for the past few years.

Thursday, 24 July 2014

The Pollination Story; part 3, specialising

This is chapter 3 in the fascinating - to me anyway! - story of pollination; see here for the previous episode. It didn't take plants long, in evolutionary terms, to devise numerous ways, visual and chemical, to be more obvious to compete with their neighbours for the essential insect pollinators. We looked at some of these strategies last time.

Another is to put out advertising hoardings - "get your lovely fresh energy-enhanced nectar HERE!" - in the form of nectar guides on the petals, to direct their customers straight to the source. They weren't the last advertisers to assume that their clients weren't bright enough to work things out for themselves!
Alpine Gentian Gentianella muelleriana, Kosciuzko National Park, New South Wales.
Pelargonium rodneyanum.
Lilac Lily Schelhammera undulata, Family Colchicaceae, Budderoo NP, New South Wales.
We see these as contrasting colours, and it's likely the insects do too, but it's not safe to assume that a butterfly sees the same colours that we do - it probably doesn't in fact. For instance many, perhaps most, insects can see much shorter wavelengths than we can - once they get shorter than what we interpret as violet, we just lump them all as 'ultraviolet', but if a butterfly could speak it would probably have names for another half dozen or so colours that we could never imagine. By viewing flowers under ultraviolet light we can see nectar-guide streaks otherwise invisible to us - but we still have no way of seeing what a butterfly or wasp sees. 

But all this was but a prelude to more and more sophisticated specialisation - after all the point is not just to have the pollen taken from you, but to be reliably delivered to another flower of the same species. Colour is one way of narrowing the field of overlap with competitors; insects see best at the yellow-blue end of the spectrum. Another is petal number (and for current purposes I'm using 'petal' loosely to include both petals and sepals). Some insects can in fact 'count' to some degree, so a major direction was towards reducing the number of petals and keeping them constant; insects learnt to associate these petal numbers – 'iconic numerals' – with a favoured food source. This was a big step forward from earlier flowers with no regular shape, and varying numbers of petals clustered randomly. It led to flat flowers with set petal numbers.

The next major move was into three dimensions - ie a tubular flower like a Daffodil or Correa. It not only excludes most pollinators - ie assisting the goal of specialising - but more accurately guides the pollinator past the flower's sexual organs. 
Brachyotum quinquenerve Melastomaceae, Manu NP, Peru.
So far, all the flower shapes I've considered have been radially symmetrical ('actinomorphic') - ie any line drawn across the flower will divide it in half. This limits the potential for variation.
Correa barkeriana Rutaceae, Barren Grounds NR, New South Wales.
The next stage of complexity was to a flower that is bilaterally symmetrical - only one line, down the middle, can divide it in half.
Wedge Pea Gompholobium huegelii, Canberra, is relatively simple.
Carousel Spider Orchid Caladenia (Arachnorchis) arenicola Perth, (below) is more complex.
In each case only one pair of mirror images can be obtained, by running a line down the
centre of the front of the flower.
The advantage of this may not be immediately obvious, but it removes the limitations on flower shape variations imposed by the requirement that the flower has to be uniformly shaped. Evolution can now tweak infinitely by altering the top or bottom of the flower without changing the other, or by changing each differently.

So, why not free yourself entirely of restrictions on variation by having no symmetry? It is intriguingly rare, but apparently some tropical bird- and bat-pollinated flowers have indeed taken this path. Unfortunately I can't offer you any examples, and any help with finding some would be greatly appreciated! 

Next time, a whole new suite of bigger and better customers!


Monday, 21 July 2014

As You Lake It

Having a couple of other matters demanding attention at the moment (ones more related to earning a living than is writing a blog post!), I thought to take the easy way out and just offer you some hopefully attractive pictures of some lakes. Inevitably I soon starting thinking more about lakes, and what they are, so my offering has become a bit more than just a series of images, and hopefully is more interesting for that.

A lake is of course a body of water, though there is no consensus as to just how big (ie how large it has to be to graduate from being a mere pond or pool); different suggestions range from a couple of hectares to 40 hectares. It can't be connected to the sea (so is usually, but not necessarily, fresh water), and is land-locked except for an inflow and outflow channel, though these are optional. However, there are several kinds of lake, based on origins and flow characteristics.

While less obvious in Australia (where we tend to be a bit light on with regard to water anyway), lakes originating with glacial activity, past or ongoing, form a substantial portion of the world's lakes, so let's start there. Glaciers can gouge out hollows which later fill with water, or dam valleys with moraine material left behind as melting glaciers retreat.
Dove Lake and Cradle Mountain, Tasmania.
Tasmania underwent major glaciation during the last glacial period, far more than did the mainland.
Lake Cootapatamba, Kosciuszko National Park, New South Wales.
These southern alps also had minor glaciation until 10,000 years ago, and Cootapatamba
derives from that. It is Australia's highest lake.
El Cajas National Park, in the high Andes above Cuenca, central Ecuador, is studded with glacial lakes,
above and below. The altitude here is over 4000 metres above sea level.

Further south, glaciers are still very much a part of the Andean landscape, and glacial lakes abound.
Lago Todos de los Santos near the Argentinian border with Chile,
east of Puerto Varas.

Lake in the high pampas, Andes east of Coyaique, Chilean northern Patagonia.
Further south still, the mighty peaks of Torres del Paine National Park in far southern Chile are not part of the Andean chain, but are actively glacial and at their feet are some superb lakes.
Lago Nordenskjold, Torres del Paine National Park.
In front of the towers (above) and with wind ripping the surface from the water (below).

In Australia, in the arid inland, many lake are endorheic - that is the flow is only into the them, and they are dry much more often than not, though they are based on vast ancient rich lake systems, with flamingoes, fresh water dolphins and crocodiles not so long ago. Mostly they are salty, because of ongoing evaporation.
Lake Amadeus, near Uluru, central Australia.
Part of a vast 'fossil' lake system, 500km long and covering 1750 square kilometres.
Lake Gilles, South Australia, in its normal state (above)
and as much more rarely seen (below, in September 2013).
Waterholes, often called oxbows, or billabongs in Australia, form when a river changes course - as often happens during floods especially - and the old bed is cut off from the main stream and fills during times of overflow from the new bed. In arid Australia such waterholes can also form in the main bed which very rarely flows, but deep holes retain water for considerable time; they are critically important to life in desert landscapes, and can have their own endemic fish and invertebrate species.
Combo Waterhole near Winton, north-western Queensland.
(It was here that the great Australian bush poet and journalist A.B. ('Banjo') Paterson was inspired
to write Waltzing Matilda, sometimes thought of Australia's 'other national anthem'.)
Cocha Salvador, Manu National Park, Amazonian Peru, at dawn.
A large oxbow lake.
Volcanic craters can fill with water to form sometimes large lakes.
Crater Lake near Kibale, Uganda.
Larger crater lake, Queen Elizabeth National Park, Uganda.
And while in that part of the world, many of the great east African lakes are formed on the great rift which is splitting Africa. Such lakes are unusual in that they are getting deeper faster than siltation can fill them up.
Lake Edward, Queen Elizabeth NP, Uganda (above)
and Lake Victoria, Entebbe, Uganda (below).
Two mighty rift lakes.

Fresh-water lakes can form in the dips behind sea dunes.
Meroo Lake, south coast New South Wales.
And unlikely as it seems, sand can support lakes well above sea level, though it is unusual. Some famous examples, 40 or so of them, are on Fraser Island, off the southern Queensland coast.
Lake Mackenzie, Fraser Island, a perched lake on sand.
So, a brief review of some lakes I have known... I hope you enjoyed the journey too.

PS I've just realised that this is the first posting ever by me without a named plant or animal, so I should rectify that.
Chilean Flamingoes in glacial lake in front of the Towers, Torres del Paine NP.


Thursday, 17 July 2014

The Pollination Story; part 2, getting noticed

This series started recently here, with the beginnings of the great pollination partnership between flowering plants and animals. From early on in the development of the partnership, competition was strong between neighbouring plant species for the services of the insects that were already being trained to associate the flowers' scents and 'flags' - petals and sepals - with an energy reward. How to be more noticeable? A very simple one is for flowers to be held high over a low-growing plant.

Silky Swainson-Pea Swainsona sericea Fabaceae, south of Canberra, a threatened species.
The flowers are waved high above the ground-clinging foliage.
Another way of course is to have huge flowers, but that's pretty risky - a single flower can be damaged by weather or by animals interested in eating it rather than seeking its nectar. A better solution is to have lots of little flowers clustered; such a cluster can last a long time by having successive flowers open over a period of time, and the loss of individual flowers is of no moment. Here are some common Australian examples, but you'll know of plenty of equivalents, wherever you live.
Firewood Banksia Banksia menziesii, Badgingarra NP, Western Australia.
As with many flower spikes, the hundreds of flowers here are opening from the base - the top half
of the spike presently comprises buds.

Rose Banjine Pimelea rosea, Cape le Grande NP, Western Australia.
Raspberry Jam Tree Acacia acuminata, Christmas Rock Nature Reserve, Western Australia.
In wattles the true nature of the flower balls or spikes is best seen in the buds, before the
numerous stamens hide the individual tiny flowers.
(The common name is from the astonishing scent of the cut wood.)
Candles Stackhousia monogyna Stackhousiaceae, Canberra.
A very common spring flower round here; the spikes are far more obvious than the individual small flowers.
The most familiar such clusters of flowers however are found in the daisies. The 'basic' daisy flower is a cluster of hundreds of tiny florets growing from a common base.
Billy Button Craspedia sp., Namadgi National Park, above Canberra.
However many other daisies have taken this sleight of hand a step further by adding 'petals', often in contrasting colours, around the head of florets. These 'petals' are in fact sterile florets whose sole purpose is to draw attention to the fertile disc florets.
Olearia tenuifolia, Mount Tennent, south of Canberra.
The purple sterile ray florets contrast dramatically with the fertile yellow disc florets.
Yet other daisies utilise colourful papery bracts - modified leaves - instead of ray florets to make the tiny disc florets more conspicuous.
Alpine Paper Daisy Xerochrysum subundulatum, Kosciuszko National Park, New South Wales.
The bracts are stiff and shiny (hence the common name).
Other unrelated plant groups have arrived independently at the same solution, with often dramatic results.
Flannel Flower Actinotus helianthus Apiaceae, Pilliga NP, New South Wales.
Here the tiny flowers can be clearly made out if the picture is enlarged, surrounded by
soft 'flannel-like' bracts.
Waratah Telopea speciosissima Proteaceae, Budderoo NP, New South Wales.
Like the related banksias, waratahs have numerous clustered flowers (though seated on a flat
disc rather a spike), but have gone further, with the big red leafy bracts to make them even more obvious.
(This is the state flower of New South Wales.)
Royal Hakea Hakea victoriae Proteaceae, Fitzgerald River NP, Western Australia.
This is an amazing plant, growing metres high in the heathland (see below); the small white flowers (here
represented by the woody fruits) are hidden down among the leathery cabbage-sized leaves,
whose bright colours draw attention to them.
Royal Hakeas in the landscape, Fitzgerald River NP.
The species only grows in this park, one of the most botanically diverse places on earth.
So far we've looked at multiple flowers - inflorescences - but I'll end today with a couple of examples of single flowers which have taken unusual evolutionary steps to become more visible.
Pigface Carpabrotus sp., Kalbarri NP, Western Australia.
The fertile stamens are in the centre of the flowers. There are no true petals - the numerous 'false petals'
are staminodes, sterile structures derived from stamens which are playing the part of petals to increase visibility.
(The fruiting structure, not seen here, is alleged to resemble a pig's head...)

And lastly, perhaps if we wanted to draw attention to plane flying overhead, we might flash a mirror. It seems that the familiar buttercups, members of an ancient flowering plant group, are doing just that!
Buttercup Ranunculus sp. Tallong, New South Wales.
The shiny petals are due to a layer of reflective subsurface cells.
Next time, we'll explore how individual flowers became more complex, to distinguish themselves from their neighbours of other species.


Sunday, 13 July 2014

On This Day 13 July: Allan Cunningham's Birthday

Allan Cunningham was one of the great botanist-explorers of Australia, but his interests were strictly in that order. He travelled in order to find new plants, and new places were good places to look for hitherto undescribed plants. However he was a very competent bushman, was keenly aware of the colony's need for viable routes between already settled areas, or from settlements to new grazing land, and was thorough in describing what he'd found.

He was born in southern England in 1791 to a Scottish father. (I keep coming upon Scots in my readings about Australian explorers and biologists, but maybe it's just that my own heritage makes me more aware of them!) He worked for a while in a law office in London, but that didn't suit him and he got work instead as a clerk in the Kew Gardens herbarium. Here he met such botanical luminaries as the great Robert Brown (another Scot! but it's OK, I'll stop that now), who in turn put him in touch with Sir Joseph Banks himself. Banks recommended that the gardens employ Cunningham as a collector - he was quite right, but I have no idea how! Banks by now was 70 years old and had already decided he no longer needed a full-time collector, but he was happy for Kew to supervise Cunningham and pay him.
Swamp Daisy Actinodium cunninghamii, Stirling Ranges National Park, south west Western Australia.
Despite the common name it is in the family Myrtaceae, with eucalypts and bottlebrushes!
It was named by the German botanist Johannes Schauer, a specialist in Western Australian myrtaceous plants,
in 1836, towards the end of Cunningham's life.
He sailed for Brazil in 1814, aged 23 - it was to be another 17 years before he saw England again. It must have been an extraordinary experience for a young man who, as far as I can tell, had never before left Britain. After two years he was ordered to sail for New South Wales, another sudden and dramatic contrast for him; he arrived in the summer of 1816, just before Christmas.

Soon afterwards he accompanied the notoriously grumpy Government Surveyor-general John Oxley to the western plains of New South Wales. Oxley was frustrated with the relative lack of success in finding new grazing lands, but Cunningham was delighted with his 450 or so plant specimens. He walked home across the Blue Mountains from Bathurst so his horse could carry the plants. 
River Oaks Casuarina cunninghamiana, Deua National Park, New South Wales.
This casuarina is only found within metres of water courses, and is the dominant tree of river corridors
in near-coastal southern New South Wales; inland it is replaced by River Red Gums.
It was named in honour of Cunningham, ten years after his death, by Dutch botanist Friedrich Miquel.
He then spent five years on a series of exploratory voyages with Philip Parker King, sailing in the little Mermaid, and later the Bathurst, right around Australia more than once. His health was suffering, but he never flagged. 
Rattlepod Pea Crotolaria cunninghamii, south-west Queensland.
This most striking big pea grows on bare desert dunes.
It too was named for Cunningham after his death, by his old patron,the great Robert Brown.
Back on land he undertook a series of inland expeditions, especially to northern New South Wales and southern Queensland (which at that stage was still part of New South Wales). He discovered the Pandora Pass, leading from the coast through the rugged Liverpool Range to the rich Liverpool Plains, formerly described by Oxley. From there he proceeded to the equally rich Queensland Darling Downs, and on a subsequent trip pioneered the route from there over the ranges via Cunningham Gap to Moreton Bay (now Brisbane). In between he made numerous shorter exploratory trips and spent some months collecting in New Zealand. He was the first botanist to visit the Limestone Plains where Canberra now stands.
Bangalow Palm Archontophoenix cunninghamiana.
Named long after Cunningham's death by the German botanist Heinrich Wendland.
(Apologies for the muddy old slide - I must get up there again some time!)
On Norfolk Island in 1830 suspected escaped convicts stole all his equipment, but the government declined to offer him compensation. Perhaps the government reasoned that once they'd escaped, the convicts were not longer their responsibility!
Hoop Pine Araucaria cunninghamii, National Botanic Gardens, Canberra.
A rainforest conifer of the east coast tropics and subtropics, and north into New Guinea.
Named by William Aiton, first director of Kew Gardens, who employed Cunningham as clerk, then collector;
however Aiton somehow mucked up the publication and it was left to Robert Mudie, much-published naturalist
and author of The British Naturalist, to sort it out in 1829.
In 1828 he requested permission to return to Britain - they were tough employers, those botanic gardens! - which was granted, after two years consideration. He lived near to Kew, spending most of five years sorting his specimens for the herbarium and writing papers on his experiences. Australia hadn't finished with him yet though. After only a year he was asked to become New South Wales Colonial Botanist, but he managed to pass the job to his younger brother Richard; like Allan he also worked at Kew as a clerk, but in his case it had been for 17 years, much of his work involving Allan's flow of specimens.
Maytenus cunninghamii Celastraceae, Tregole National Park, southern Queensland.
Named by Sir William Hooker, who succeeded Banks as director of Kew Gardens in 1841,
naming the small tree again well after Cunningham's death.
It is widespread across northern Australia in dry forests and vine thickets.
Richard followed in his brother's footsteps across the plains beyond the Blue Mountains, but was killed by Aboriginal people with whom he had been camping, apparently due to cultural misunderstandings - it seems that he might have been delirious with a fever at the time. This time Allan couldn't refuse the invitation to replace him and took up the position in 1837. What he hadn't realised was that the job included responsibility for the governor's vegetable garden; he baulked at having to supply the governor and his colleagues with carrots and cabbages, and resigned to resume what he termed the "more legitimate occupation" of plant collecting.
Ancient Myrtle Beech Nothofagus cunninghamii; a magnificent old temperate rainforest
tree in Weldborough Forest, Tasmania.
Another one named by William Hooker to honour Cunningham.
In another visit to New Zealand he apparently contracted pulmonary tuberculosis - he certainly returned from there with it - and died in Sydney in 1838, having had to give up a place on the Beagle surveying north-western Australia.

I've always admired Cunningham for his quiet passion for understanding the natural world, and his self-effacing stoicism and commitment. (And of course for his Scottish ancestry.) Wherever I go it seems there are plants, and even lizards, which help me to remember him.
Cunningham's Skink Egernia cunninghamii, a common colonial-dwelling big skink which inhabits
mostly rock outcrops in our part of the world.
Named in 1832 by (I am almost certain) zoologist John Edward Gray, later of the British Museum.

Tuesday, 8 July 2014

The Pollination Story; part 1, beginnings

I think the story of flower pollination is one of the great narratives of our planet, and I love telling it, though preferably out in the bush surrounded by the flowers and their attendant animals. However that's not very practical for us, so let's make a start here. It's too big and beautiful a story to tell in one sitting and I anticipate it will take at least half a dozen chapters, which will appear from time to time.

The early land plants - whose ancestors came ashore into shallow estuaries and coast lines only some 450 million years, after nearly three billion years of life in the oceans - had no flowers, no seeds. Like their aquatic ancestors they relied on water to permit sperm to swim to eggs. In time dominant groups of plants developed the seed, a wonderful package of fertilised embryo, with food and water to start it out in life, insulated from the drought and cold of the world so that plants could at last spread into the bare inland.
An idea of how the entire world looked until about 360 million years ago, when the evolution
of the seed allowed plants to colonise the forbidding wastelands.
Lava fields, Bartolomé, Galápagos.
A related development was the wrapping of the sperm into its own tough packaging, which we call pollen, and which was cast to the winds. It's a hideously inefficient system - the chance of a pollen grain landing on the female receptacle of the right species at the right time is minuscule, and only a fraction of a fraction of  a percent of pollen produced forms a seed. As a result, vast quantities of pollen must be produced. Nonetheless, it works and conifers and cycads - the great dynasties of pre-flowering seed plants - dominated the world for some 250 million years. Indeed in vast areas of high altitudes and high latitudes where conditions are too harsh for animal pollinators, they still do dominate.
Black Cypress Pine Callitris enlicheri, Family Cupressaceae, Cooma, New South Wales.
Female (large woody) and male (small and pale brown) cones.
However, some 130 million years ago in China, according to the fossil record (longer ago, and perhaps in western Gondwana, according to some genetic evidence), plants took the next Great Leap Forward.

Archaefructus liaoningensis, one of the oldest known flowering plant fossils.
Courtesy Wiki Commons.
Pollen is high in protein, and doubtless early beetles - ancient insects - blundered around collecting some to eat, and in the process accidentally transferred some to other plants. And here was an evolutionary opportunity - if the plant could persuade the beetle to selectively take pollen to another of its species, it would be a massive advantage. It would be like addressing an envelope to a destination rather than dropping millions of identical letters from an aeroplane in the hope that one or two fluttered to the right doorstep, as the conifers were doing. 
Beetle on Xanthorrhoea flower spike.
The early beetles weren't the ideal carriers, relatively clumsy, hard-shelled and (it has been
unkindly suggested) not all that bright!
For effective pollination, plants need pollen-carriers which could visit relatively distant populations of the same plant species. The arrival of more mobile insect groups such as flies, bees and wasps, moths and butterflies, and even more modern beetles, with better sensory apparatus than the early beetles, provided an immense opportunity and, for most of the past 100 million years, the evolution of flowering plants and insects has proceeded as an inextricable partnership.
Native Bee on Xerochrysum sp., National Botanic Gardens, Canberra.
The underside of the body, especially the thorax, is covered with yellow pollen,
sticking to the hairs.
Fly, family Acroceridae (thanks Susan!), on Xerochrysum sp., National Botanic Gardens, Canberra.
Pollen can be seen adhering to the legs.
See-through butterfly on daisy, Milpe Reserve, north-west of Quito, Ecuador.
In particular, butterfly proboscises are known from 190 million year old fossils - much older than the oldest known flowers - presumably originally for taking up water and resin, but they were pre-adapted for nectar and as the flowering plants exploded in diversity across the world, so did the butterflies and moths.

Male Australian Yellow Admiral Vanessa itea on Xerochrysum sp., National Botanic Gardens, Canberra. Note coiled proboscis.
Pollen wasn't a great reason for insects to visit flowers, from the point of view of either party. It comprises complex proteins and isn't easy to digest, and of course the last thing the plant 'wants' is to have its pollen eaten. (I'm talking here in evolutionary terms, not really being anthropomorphic!) Further, the worst result of all would be having the insect carrier deliver the precious pollen uselessly to the wrong flower, ie of another species.

So two problems needed to be solved by the evolving plants. The insect had to be given another reason than pollen to visit, and the flower had to be visible, and recognisably different from the competition.

The first was solved by the development of a special gland called a nectary in the base of the flower, which produced a simple sugar solution, nectar - an energy source in other words, which was a great prize for any animal. Its sole purpose was to bribe the insects to visit. The second was by an increasingly complex system of 'flags', based initially on leaves, which we now know better as petals and sepals. And the pollinators, the early flies, bees, wasps, butterflies, moths and flower beetles, were quite capable of recognising and remembering these flag messages.

A mighty and earth-changing partnership was established.

Hoverfly, Syrphidae, on Bulbine bulbosa, Asphodeliaceae, Canberra.
As it accesses the energy treat in the nectary, it is encountering the pollen
on the fluffy anthers and the waiting club-like female stigmas.
Later, another and more distantly effective signal was added, to bring potential pollinators within sight of the petals. This was scent, another chemical released to the breezes. Poets have waxed lyrical on flower scents, but as usual they weren't developed for our benefit. The poets shouldn't be too disappointed at this realisation however - if blowflies were better pollinators, more flowers would smell of rotting meat rather than of roses!
Wilga Geijera parvifolia, Rutaceae, western New South Wales.
This rather lovely spreading tree of inland Australia, is one which does
attract blowflies to its somewhat putrid-smelling flowers.
(Ironically it is in the same family as famously sweet-smellers such as oranges and boronias!)

In the next episode, in a week or so, I want to explore how flowers and inflorescences (the arrangement of flowers on a stem) became more and more complex and specialised.