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Wednesday, 24 April 2013

Water dragons and sundews

Tuesdays, all going well, I am out and about at the sanctuary at North Head. Sometimes I do Fridays, and one week I did both, but it's good to get out and potter.  Right at the moment, work is a bit stressful as we bring home a giant book project in half the normal time, but when I can, I go out to play.

I have taken on a project, trying to get spores of a fern called Gleichenia to "germinate".  I will say more on this later, if and when I get some success, but I will be trying two methods: one is a traditional method using a piece of brick in water in a covered ice-cream container.

The other is a method I developed about 40 years ago, using what I call mud agar.  I get some mud, put it in water, boil it thoroughly to get the life forms out of it, decant, boil again and add 1.5% agar-agar, then plate this out into Petri dishes.  The plates are then scattered with spores and left in light, misted with water every day or two—but I will come back to that.

The main thing is to get spores, and as I don't know much about this fern and when it forms spores, I am dabbling around, taking samples and trying things out.  I am very much a dabbler at heart, so that's fine by me.

The fern grows mainly in swampy places, so we have three main sites where I can sample.  Yesterday, I set out to sample the two nearest sites, one near a drain and one near a swamp.

The drain paid off, but as I was leaving, I saw a large and apparently very dead water dragon. I reached down and moved its tail. The body was desiccated, dark, smeared with mud, but it seemed to be otherwise intact.  I decided to rescue the corpse, just in case one of the volunteers was looking at stomach contents, but mainly so I could attempt to rescue the skeleton.

As I grasped the tail, the dragon came to and ran about half a metre, fetching up in the long grass and glaring at me.

It then remained there peacefully enough, and allowed me to take several shots. Then we nodded to each other, and I went on my way, heading for the swamp.

Bu the way, the shot at the top is a juvenile water dragon that had taken up a sunny wall in one of the nursery houses.

As you can gather from these shots, the water dragons are remarkably patient with pesky human beings.

Off, though, to the swamp. Most of the walking tracks are on steel mesh, which allows things to grow without being trodden on.

The mesh also allows people to penetrate the swamp without getting muddy, seeing things that would otherwise be hidden, but as I noticed, and as you can see on the left, you need to keep your eyes peeled! Those plants are about 30mm (a bit over an inch) across.

These little plants are sundews, Drosera sp., and almost certainly Drosera spatulata, which, when I were a lad, was always mis-spelled as Drosera spathulata. Apparently D. spatulata is correct.

The members of the Drosera genus are all carnivorous plants, or to be precise, they are insectivorous plants which catch insects in the sticky "dew" on their hairs. The "dew" is sticky, so it traps insects, but more to the point, it contains proteolytic enzymes, and the leaves respond to the taste of "soup" by curling over, as you can see in the 3 o'clock position in the close-up shot.

This curling brings more enzymes in contact with the victim, breaking it down faster.  Bits of meat and even cheese will bring the same response.

Some years ago, I taught in a school quite close to North Head, and one day, I told some of my students that as a special treat, I would take them out to see some carnivorous plants that I had found near the cricket nets.

One kid who was usually completely out of it in class got all excited, but it turned out later that he thought I had said "cannabis plants". All the same, he fed some of them with scraps of meat and went back to visit them later. All sorts of people can get interested, if somebody takes the time to show and share!

I was under the impression that the sundews were confined to the eastern states, but when I was out at Wave Rock a year or two back, doing some desultory research, I found this specimen at the base of the granite. The coin is 2 cm (0.8 inch) across.

So for my friend Woofie Wotsit, here's proof that I do indeed acknowledge Westralian plants.

This is the natural result of being the son and husband of two Cottesloe girls!

And if you haven't heard of Wave Rock, here it is: that's one of the said Cottesloe girls in the shot. Chris wasn't pretending to surf, just seeing how easy the slope was to walk up backwards, but it was too good a shot to miss. The rock is granite, the streaking is from algae, and it's about 400 km east (ish) of Perth.  Just Google Wave Rock!


Footnote:

It seems  that I visited sundews once before. I had forgotten that!

4 comments:

  1. Wish I could have seen your face when the corpse came to life!

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  2. It held a look of annoyance, mainly. I was already thinking where I had left the chicken-wire cage I use to reduce bodies to bones, without scavengers making off with the bones.

    ReplyDelete