Pod Growth

Day 314: When something dries out, it shrinks. That's an inescapable fact. And logically, the more water it has to lose, the rate of shrinkage will be different. Obviously, a cherry tomato would shrink more than a similarly-sized walnut meat simply because it has a higher water content. Nevertheless, having seen dried milkweed pods, I was not expecting fresh ones to be quite so enormous! These are already four inches long. Taking a tangential detour in the discourse here, and having come face-to-face with my own mortality at my annual checkup, I have to wonder if the next owner of this property will appreciate the inheritance of botanical diversity my garden supports: milkweed, Akebia, kiwi vines, gooseberries, a medlar tree, and hiding under leaves, a treasured stick which sprouts aqua-blue fungus with the arrival of autumnal humidity.

We Have Pollination!

Day 291: We have pollination! Yes, my milkweed plants are making pods! And I cannot credit the success to my intervention because the flower I attempted to pollinate by hand is not among those with swelling ovaries. That said, there are at least a dozen strikingly obvious developing pods on the plants which flowered earliest, and I think there will also be some on the plants which came into bloom a little later. It's too soon to tell with those, although it looks like a few of the flower stems are beginning to curl (as opposed to drooping). That was what caught my eye first: one curled, plump flower stem held above a mass of withering flowers. Closer examination revealed an ovary starting to swell, and then as I raised my eyes, I saw this pod, about as big as the end of my thumb! Then I really started peering in among the fading flower clusters, and saw that the pollinators had done the job I'd failed to do. Finally, I'm going to have milkweed pods!

Bee Hopeful

Day 281: I have good reason to "bee hopeful" that my milkweed plants will produce seed pods this year. They are absolutely covered with a large assortment of insects...stinging insects, mind you!...who visit one flower after another. Bees dominate the mix, but there are wasps of every size from miniscule to man-eating, so I stood well back and zoomed in for the photo. Can I identify them? No, although I think I can safely say that these two are honeybees, a species to which I am deadly allergic. Was I worried that I would get stung? Not at all, because they were firmly focused on the work at hand, gathering nectar from the sweet-scented flowers. Surely sombody's going to get pollinia caught on a leg!

Milkweed Reproduction

Day 272: The first phase of this project consisted of learning to identify the reproductive structures of Asclepias syriaca, Common Milkweed. You'd think that milkweeds kept the family jewels in the same place as other plants do, but as it turns out, the flower is rather different in that it centers on a gynostegium (new word for me!), which is comprised of fused stigmas and stamens. What lay people would call the "flower" (the white part, in this case) is the corona. It consists of hoods and horns (five each). The petals of the flower depend beneath it. Between hoods, a careful observer will note a swollen brownish bump at the inner end of the stigmatic slit (see center image). This is the corpusculum. It is essentially the "bear trap" in which an insect's leg can become ensnared. Attached to the corpusculum are two pollinia, sticky agglomerations of pollen. In the instance of A. syriaca (or at least those in my garden), the corpusculum and attached pollinia measured something in the neighbourhood of half a millimeter long. I was able to tease two "units" out using the microscope and a dissecting needle, but once on the tray, I could barely see them with my naked eye. Nevertheless, "sticky" was the operative word. They gummed themselves to the tip of the dissecting needle nicely, and I was able to transport them to the garden. As to whether or not I successfully poked them into the stigmatic slit of a second plant remains to be seen. I had no way to magnify the flower while keeping both hands free to perform the cross-pollination. There was an unexpected bonus to this experiment: I discovered that milkweed is deliciously fragrant as I stood there with my beak in the blossom, pretending I was a bug.