cycas cairnsiana, a primitive masochist
Author |
Message |
Peter Richardson
Joined: Mon Oct 29, 2007 12:16 pm Posts: 1472
|
cycas cairnsiana, a primitive masochist
I spent a couple of hours today looking at a sizeable colony of C. cairnsiana about 70 kilometres
inland from Mareeba, where I live. It covers a stony bluff at one end of a C-shaped ring dyke made
of pinky-buff rhyolite and granite, in dry savannah terrain. The geology is actually a bit more complex
because there is at least one patch of basalt there as well. The sky is grey because the monsoonal
low pressure trough is sitting over this area today. It gives similar weather to a warm or occluded
front in temperate latitudes - a horizon-to-horizon pall of stratus cloud, mild temperatures and long
periods of continuous rain.
The bluff was severely burnt off in a bush fire in the most recent dry season and most of the cycads
were defoliated. However, nearly all have come back. I think the bluff must be prone to especially
severe fires because (in contrast to the surrounding well wooded landscape) there are almost no
shrubs, very few trees on it, and those there show much evidence of charring. Hence the cycads
have it almost to themselves, along with the partial ground cover of soft annual and herbaceous plants.
Evidently it is a highly fire resistant species. There are plenty of young seedlings with only one or two
fronds on the ground.
That they can recover from the bushfires suggests they store plenty of reserves in their rather fat
caudexes, but also that the caudexes themselves must be in some way particularly fire resistant.
Where the stony ground you see in this photo above gives way to normal soil, the cycads come to
an end. So they seem doubly masochistic in choosing both a severely burnt and a very stony micro-
habitat. I only saw granite rocks the first time I came and looked at this colony but walking round
more today, I found they don't actually give a toss what the rocks are - some are on granite, some
on rhyolite (same chemical composition as granite but fine grained) but some are on basalt (low quartz,
high in ferro-magnesian minerals and basic in reaction). It seems they specialise in occupying rocky
ground first and foremost, irrespective of the chemical composition of the rocks.
At the present time most of them are sporting new crowns which are a sickly looking yellow green.
I'm not sure if this is just a temporary stage they go through before becoming the darker, glaucous
green, or whether it is a sign of stress as a result of having been completely defoliated a few months
ago. The ones that are still unfurling their new crowns are a striking silvery colour due to the
white indumentum all over the new fronds. This ages to rusty orange, then over time gradually wears
off altogether.
Below are a few more photos of individual plants.
A plant with bifurcated caudex.
This looks more like some form of side branching. The side branch has attained the mature glaucous
coloration, while the main crown is still silvery while unfurling.
Rather more adventurous exercise in side branching.
The shaggy dog look.
Going all out for the Dog's Dinner look. I don't know what causes this, whether it is
genetic or a pest or disease.
Silvery unfurling crown
Macro photo of uncoiling pinnae
The silver, felty indumentum on a frond nearly fully unfurled. Notice how it is water
repellent.
Big dangly balls!
Erect male bit!
Beautiful, large flowers of Hibiscus meraukensis, which grows among the cycads.
It is a fast growing annual, only seen during the wet season. Native right across the Top End
from here to the Kimberley in Western Australia, also the Torres Strait Islands and PNG.
There's a whole gaggle of these blue flowered Tradescantia type things that grow
in savannah country round here. Some have three equal petals, some like this have the
bottom petal reduced to an insignificant little flap.
A red kangaroo that momentarily eyed me before bounding off.
Last edited by Peter Richardson on Mon Feb 11, 2008 9:18 am, edited 2 times in total.
|
Sun Feb 10, 2008 11:24 am |
|
|
Aloeysius
Joined: Sun Dec 09, 2007 9:16 pm Posts: 193 Location: The Netherlands
|
...stunning photo's...really breathtaking Peter...
|
Sun Feb 10, 2008 11:41 am |
|
|
Kev Spence
Site Admin
Joined: Mon Oct 29, 2007 3:59 pm Posts: 10902 Location: Loughborough, Leics, central UK
|
WoW...................you have certainly out done yourself this time Peter that must be the best photo post on this forum so far and probably the UKO as well.
Did you know about these cycas from someone or did you just happen on them?
I think we would probably fly to Australia just to see the sight you have witnesed you are a very lucky man.
Jackie has been relegated off my PC wallpaper its now C. cairnsiana
|
Sun Feb 10, 2008 12:01 pm |
|
|
David Matzdorf
Site Admin
Joined: Mon Oct 29, 2007 4:06 pm Posts: 5321 Location: Islington, London UK
|
It's an unusually vivid set of photos, even for you. You have got the light just right, just as you described it, and the curious explosive post-fire flushing of the cycads in every possible stage of development.
Must have been a wonderful experience to come across these. As Kev asks, did you know they were there or did you just stumble upon them?
|
Sun Feb 10, 2008 12:07 pm |
|
|
Peter Richardson
Joined: Mon Oct 29, 2007 12:16 pm Posts: 1472
|
Um...thanks David and Kevin, actually most of the photos are over-exposed and the colour balance
is not right, presumably because the camera was struggling to compensate for the heavy pall of cloud.
I knew they were there from a previous trip out west. Although I have no desire to cultivate them, its
certainly very nice to be able to walk around a natural colony like that. Next cycad mission will be a
wild grove of the rainforest-dwelling Lepidozamia hopei, but at present the torrential rains preclude that.
|
Sun Feb 10, 2008 12:15 pm |
|
|
David Matzdorf
Site Admin
Joined: Mon Oct 29, 2007 4:06 pm Posts: 5321 Location: Islington, London UK
|
|
Sun Feb 10, 2008 1:21 pm |
|
|
Kev Spence
Site Admin
Joined: Mon Oct 29, 2007 3:59 pm Posts: 10902 Location: Loughborough, Leics, central UK
|
|
Sun Feb 10, 2008 1:32 pm |
|
|
Charles Wychgel
Joined: Fri Nov 02, 2007 10:09 pm Posts: 757 Location: Algarve/Portugal
|
|
Sun Feb 10, 2008 3:26 pm |
|
|
Stan
Joined: Wed Oct 31, 2007 5:52 pm Posts: 10687 Location: Hayward- S.F. Bay area Ca.
|
Darn,tried to make panoramic photo no.4 my Monitor background. Too squeezed. Photo no.3 looks fine.. Old style monitor.
I do have Windows Xp . Ugraded three years ago from Windows 95..
And i will pass on my thought that those plants would be poached out in a weekend in America. It's too seriously sad what goes on here..
|
Sun Feb 10, 2008 7:55 pm |
|
|
Mark Longley
Joined: Mon Oct 29, 2007 6:45 pm Posts: 877 Location: Auckland, NZ
|
What a fantastic set of pictures. The most extraordinary we've seen on this forum yet!
_________________ www.thefernhouse.moonfruit.com
|
Mon Feb 11, 2008 6:44 am |
|
|
Jonathan Poston
Joined: Tue Oct 30, 2007 11:08 am Posts: 266 Location: Eastbourne, Sussex, England
|
Thanks peter for the pictures.
They were remarkably evocative as David said, seemingly otherworldly in my view and it was not hard to imagine a Triceratops or two wandering around the cycads.
|
Mon Feb 11, 2008 7:29 am |
|
|
Peter Richardson
Joined: Mon Oct 29, 2007 12:16 pm Posts: 1472
|
thanks all, glad the pics were of interest. C. cairnsiana is in fact under pressure from illegitimate
collecting, though not as dire as Stan mentions in the United States. I was very conscious the whole
time I was looking round that I could be taken for a plant rustler, although very few vehicles passed
by on the adjacent road. Another risk is that by being seen wandering round with camera, it may
prompt others to think there is something valuable there.
Talking of dinosaurs, when I go out west, the sentiment uppermost in my mind is that I am in a landscape
that 'once was', since the low hills, now covered in so-boring eucalypt savannah are the worn down stumps of former mountain ranges, from a time when Australia was further south, wetter and cooler. They probably were
covered in magnificent Gondwanic forests of Araucariaceae, Podocarpaceae, Winteraceae, Elaeocarpaceae,
ferns, and who knows what.
Since plate tectonics will eventually grind to a total halt as the earth's core gradually cools, at some point in the future, the whole world will be as worn flat and boring as inland Australia. And probably as hot, since the sun's luminosity will increase with age.
as it says - welcome to Hell.
|
Mon Feb 11, 2008 8:58 am |
|
|
Nick Macer
Joined: Tue Oct 30, 2007 12:42 pm Posts: 1284 Location: Gloucestershire, UK
|
Particularly nice to be greeted with on a Monday morn Peter.
What I have always wondered is how your shots are always displayed so sharply on here. No matter how perfect my photos are, the deterioration that comes with downsizing and conversion to JPEG means they always look slightly fuzzy when seen on here. Are you sharpening or what?
_________________ Purveyor of good things
www.panglobalplants.com
|
Mon Feb 11, 2008 10:50 am |
|
|
Zac in NC
Joined: Wed Nov 07, 2007 6:35 pm Posts: 1008 Location: Raleigh, NC
|
Your Tradescantia type thing is a Day flower, a Commelina, which most have the 3rd petal reduced.
Great pictures.
Zac
|
Tue Feb 12, 2008 3:47 am |
|
|
Peter Richardson
Joined: Mon Oct 29, 2007 12:16 pm Posts: 1472
|
Thanks Zac - if I could only remember to ask them while at work, my employers probably know its name.
Nick - I have found that optimal sharpening treatments vary according to the camera that images were taken with. I mostly use Hewlett Packard Photosmart Premier when I have a large number to process for display, as in this thread, but sometimes I use Adobe Photoshop as it has finer control. As well as sharpening, I also frequently make small gamma corrections, small exposure corrections, and less frequently, colour temperature and colour saturation corrections with these two programs.
Peter.
|
Tue Feb 12, 2008 11:27 am |
|
|
|
Who is online |
Users browsing this forum: No registered users and 32 guests |
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum
|
|