Complex Numbers

Dahlia Dreaming

And now here's another one for "Journalistic Intentions"  [18+]...

Dahlia Dreaming  

A good number of my "why the hell is it called that?" questions popped up before there was an internet. As a kid on a farm, I got to know lots of different cultivated plants—whether fruit, vegetable, or flower—whilst perusing a seed catalog. A paper one. That came through the postal mail.

This led to a lot of "why the hell is it called that?" moments that my parents, who were what passed for Wikipedia for me in those days (they'd eventually buy me an actual encyclopedia volume set, which I actually read and then promptly forgot most of), had no answers for. "Go look it up." Where? We live on a farm.

But I do remember that one of these moments was for the flower known as a dahlia. It seemed an even odder moniker than most plants' names, but the seed catalog didn't have much to say about it. It probably listed the botanical binomial, but I don't remember that. It's dahlia pinnata, according to Wikipedia, and while it's native to Mexico and Central America, it's not to be confused with a piñata. But as with many other cultivated plants, there are several subspecies. It gets confusing and beyond the point of this entry.

Nor is Wikipedia  much help with the etymology of the name. It seems it might have been named after a botanist named Anders Dahl. Which seems bogus to me, a typical European appropriation of an American species. The least they could have done is mangle one of the native names for the thing, like they did with, say, the raccoon. Except for the French, who call them washing rats, which is unfair to rats, who are often quite fastidious.

Also, I can't be arsed to find out if Anders Dahl was ancestral to the far more famous Roald Dahl.

None of which was what I set out to write about; I just did my usual assuming that if I don't know something, then no one else does, either. I have my parents to blame for that, too.

No, what I wanted to note, apart from the excellent use of depth-of-field in the photograph the title links to, is the petal pattern.

Those aren't true petals, incidentally. Each one of those petal-like pieces is a flower unto itself. But that's a bit like arguing whether a tomato is a fruit or a vegetable. No, what struck me is that the arrangement of the florets is similar to other petal and/or leaf arrangements found in nature, such as in sunflowers or artichokes: an instantiation of the Fibonacci sequence and the Golden Ratio.

Once you notice that particular spiral arrangement, you can't ever miss it. You can even find it all over the Mandelbrot set (which involves complex numbers), if you know what you're looking for. There are solid reasons for plants taking that general form (some animals, such as mollusks, do it, too), and none of them is that plants can do math. No, it's a bit complicated, but, basically, it's because it's easy and efficient.

I can appreciate that.