I've probably mentioned that I'm interested in wildflowers. They're one of the highlights of springtime in Silicon Valley. Yes, we have tilt-up buildings and endless shopping malls along El Camino Real, but almost everyone also lives within just 5 miles of some kind of open / green space with wildflowers gracing the stage. Since I grew up in LA, this springtime spectacle still amazes me.
One of the most common wildflowers in the area is mustard, which fills fields to make a brilliant yellow landscape. Supposedly sown by the Spanish missionaries when they first came to Alta California, they're pretty much ubiquitous.
I was sketching one particular plant last year when I noticed a really odd thing. I only had a few minutes to sketch, so I did a quick drawing and then left, vowing to return the next day and finish. But when I came back and sat down, I noticed that the flower stem was in a different position than I'd left it. It wasn't just pointing a different way, but the flower stem had rotated slightly around it's long axis. I only noticed this because I went back to draw the same stem / same flower, and found that it had moved with respect to the background.
What's going on here? I got curious about this and started to search for an explanation of this behavior. (Yeah--think about it.. .this is plant behavior.) I know that some flowers--sunflowers spring to mind--follow the sun across the sky, but I'd never heard of any flowers rotating on their stem from day-to-day.
The challenge question should be obvious by now... What's this rotating behavior called? How can I look up more more information about what's really going on?
Note for teachers and librarians: This is a fairly sophisticated question, but representative of the kind of question kids have. They don't know any of the unique and specific terminology that the biology/botany books would use to describe this, and chances are that you don't know it either. This is where a little search skill really helps out..