Today more sketches of the Crown Flower, trying to concentrate while I listen with growing dismay to the swine flu reports. I am trying to be optimistic as in a week’s time I am due to fly home to the UK for a long visit…most of May. I am so looking forward to it, so I am just thinking positive.
I was looking in more detail at the flower head and the leaves. The structure of the flower is so odd. There are 5 sepals only seen from the underneath of the flower, then 5 petals which do at least look like petals. Then the central “crown” part which consists of 5 stamens, the buttress like structures, which are joined with the filaments to form a structure called a “gynostegium”, a fusion of the male and female parts of the flower.
This superb photo of a White Crown Flower by G D Carr from the Hawaii Education dept here shows the top of the crown, where you can see 5 little black points.
These I think are called the glands and if you can get a scalpel in at this point you might be able to extract the “pollinia”. These are the structures which hold the pollen, not loose pollen as we usually imagine, but flat waxy pollen drops, in pairs, attached to the gland.
Here is the scan I took yesterday after I had found the pollinia. It is tiny, just 2mm long, but scanning it at high res did give me a reasonable result.
Crown Flower Pollinia
Somehow… and I am still not entirely clear how this works with this particular flower, an insect has to attach one of these to its leg and transport it to another flower.
If you are interested in milkweeds, there is a stunning web page by Brian Johnston with wonderful macro/micro photos and a clear explanation of the intricate process of the pollination of the Common Milkweed Asclepias syriaca here. The milkweed structures are all basically similar but I think I might email him to ask if he can explain exactly how it works with this particular flower… How does the insect (probably one of the red milkweed bugs) get these particular pollen sacks on its leg???. I had to work quite hard to get the thing out, but then, as we say in Lincolnshire, I probably wasn’t holding my mouth right.. 🙂
More Crown Flower Sketches
There is no getting away from the fact that I am late with this next submission, but yesterday I did get 25 illustrations sent off to the book designer. But now I have to get down to it and with no procrastination time left I decided to make a study of the Crown Flower, Calotropis gigantea, or Giant Milkweed. It’s a strange season here, I remember well from last year how things are between flowering and seeding and, while I didn’t want to repeat myself, this curious plant has enough of a challenge to keep me interested. I drew its intriguing flower here last year. It is an odd one and so rigid in its structure as to be quite unflower like.
Because this assignment has to include some dissection I have spent most of the day cutting up a couple of flowers and trying to see the complicated pollination structures. Surprisingly I did find the TINY pollinarium, just 2 mm long, and put it on the scanner to enlarge it. The whole pollination process is very complicated .. more tomorrow.
Today just sketchbook work, thoughts about layout and some colour notes.
Giant Milkweed Sketches
After 6 months of visiting Leu Gardens and recording my haphazard finds, I have written about and sketched over 120 of the different plants, flowers and trees. However if I were ever to feel at all pleased with what I have done, the amount still to do, see, discover and record is overwhelming. Sometimes I forget there are 50 acres of land ranging from neat and tidy rose garden to the gloriously unruly, tropical jungle.
My trip to Leu on Thursday took me to areas of the garden I don’t often visit. The South Woods are very quiet and secluded with tall majestic oaks, pines, sweet gums, hickories and scores of camellias The gardens are well known for their camellias, over 2000 species. There is nothing obviously showy here at this time of year but it is a lovely place to wander and on Thursday I saw 7 different oaks, discovered the second Sausage tree, watched the squirrels and woodpeckers busy in the tree tops, and I even found a Butcher’s Broom plant (see post here) which was a complete surprise. The perimeter paths are the least busy and I must have walked for an hour without seeing one other person. Here two ancient Live oaks arch over one of the South Woods paths.
I then revisited the Horror Tree to see if there was evidence of the “bones”. There were quite a few old leaf stalks around and I even found the soggy and rotting remains of 2 pods which I brought back with me. They are outside drying, in the hopes that one or two seeds may be still intact.
The Butterfly Garden is always on my rounds too at some point. It is more or less at the heart of the garden and a pretty place to sit for a while and watch the many different fluttering beauties which are attracted there. Very often I meet Joel who looks after this particular garden and takes care of the caterpillars which as gardeners know are something of a mixed blessing. But, when I say “takes care” I mean very much in the caring sense. On Thursday he walked past with a handful of passion flower leaves and I saw bouncing around on the back of his cart half a dozen big stripy caterpillars.”Gotta get these little fellas off to the nursery”, he said.
The pretty Balloon Milkweed Asclepias physocarpa grows in the butterfly garden too. Its unfortunate green hairy pods will ensure giggles and have secured it some blunt but fair colloquial names, Devils balls, Family jewels etc. In a vain attempt to deflect attention from its obvious attributes it is also optimistically called the Swan plant. The pods are a light as, well.. a balloon, and contain fine downy seeds which float round the garden and self seed, so it can be found popping up almost anywhere.
It is much loved by the Monarch butterfly caterpillar, but also it seems, by the delightful red and black assassin bugs. I have seen them before on the other Asclepias flower I drew, the beautiful Crown Flower here. They come under the category of beneficial bugs patrolling the garden to keep down the insect pests including aphids, and mosquitoes. They also eat caterpillars, so I guess Joel has divided loyalties. nothing in the garden is straightforward is it!
If you like bugs, Whats that Bug site here is fascinating and some particularly gruesome photographs.
The actual milkweed flowers have a very unusual structure and pollination method which I will return to another time as I intend to go back to the crown flower to make a colour study.
Balloon Milkweed and Bug