Can you smart people help me? I have a basic understanding of pollination. I know about the birds and the bees. I am looking for more detail, though, and I’m hoping some of you kind people will be willing to help. I have read and looked and searched, but there are still gaps in my knowledge.
I’ve attached a close-up of a flower head of a member of the Asteraceae family, Symphyotrichum genus (specifically Symphyotrichum lateriflorum). The flower on the right which I mostly cropped out had likely been thoroughly pollinated. The one with the yellow disk florets is just beginning and perhaps hasn’t been visited yet (I think). I’m referring to the one on the left.
Are the arrows I drew pointing to the styles? Do they have sigmas at the ends, and if so, why can’t I see them? Is this pollen on the ends? Is this prior to pollination? Did the style elongate from the disk floret with the pollen on it, or pick it up on the way out? When insects pollinate composite flowers like this one, what part of the flower contains it and to what part of the flower does it need to go? Isn’t the ovary at the bottom of the disk floret, and it needs the pollen? Does the ray floret also touch the ovary? I believe I understand that the nectar is there to attract the pollinators, but where is it?
Why do we have both rays and disks? (You can maybe ignore that last question. I sound like a 3-year-old discovering the world and words at the same time.)
Also, would someone help me with the term “corolla”? It seems to be used interchangeably with other terms. I’ve looked it up, seen diagrams, but still when I read it in florals, journal articles, etc., I often don’t know what part(s) are being discussed.
Image credits and license:
Author: Cathie Bird
Originally from: https://www.flickr.com/photos/39993830@N05/8572439623
Modified by Elizabeth Ballard cropped and added text.
License link: https://creativecommons.org/licenses/by-sa/2.0/deed.en