She Loves Me, She Loves Me Not

The season is full of Daisies - which botanists call Composites. And these "flowers" are indeed composed..., each daisy is a head of flowers (a particular kind of inflorescence) made up and masquerading as a single flower. When you pull out, petal by petal, the parts of a daisy as you alternate between being loved or not, you are not simply pulling single petals from a flower. You are tugging individual flowers (little flowers called florets) from a cluster that looks, for all the world, like a single flower.

If you break a daisy flower apart, the florets will stand out more clearly. In many cases, when the heads are classically daisy-like, you will actually discover the head is made of two kinds of flowers. Each of the prognosticating petals that wants to be pulled out comes from a single flower - which we call a ray, because it radiates from the head. There are other even more minute flowers that fill the center of the head, which we call the disk florets. These florets are more symmetrical, each one showing five little angular lobes that represent individual petals that make up the corolla. If you turn your attention back to the rays, you may see little teeth at the tip of a petals, teeth that reflect the same lobes seen in the disk flowers.

The base of each floret is the part that becomes the fruit, so it is the ovary. Since it develops below where the other flower parts emerge, we say this is an "inferior" ovary. All daisies have inferior ovaries. Each one matures into a dry, hard one-seeded fruit, which botanists call a nutlet. So what nutlets do you know. Well you certainly know the Sunflower seed - each one develops inside the inferior fruit of a Sunflower floret. So a Sunflower is, pretty demonstrably, a daisy.

But there are thousands of different kinds of daisies, different kinds of composites. Dahlias, Zinnias, Chrysanthemums, Marigolds, Calendulas, Liatris, Edelweiss, Achillea, and even Lettuce and Artichokes - these are all composites. Most are pretty normal, at least for a daisy, and have both ray and disk flowers. But whole groups of daisies produce heads of florets that are fully of the disk type, and there are other groups that produce heads made only of ray florets. There are even a few, really odd composites, in which the head has a single floret. With the shrubby Coyote Bush (Baccharis), whole plants produce flowers that are either female (no stamens) or male (no pistils.) In these, the heads of flowers on one shrub look entirely different from those on another; the males look very different from the females. So these simple possibilites introduce quite a range of possibilities in biology and appearance.

At times we have seen political movements that propose we make the Sunflower the national flower. I remember a Senator Dirkson who loved Marigolds, and wanted to make the Marigold the US National Flower. If that ever happened, we'd have to call it the National Inflorescence.