I appreciate the garden. Sheri and I work hard on it and have for 20 years. We carved it out of a very ordinary suburban backyard with a rusting swing set, but some great trees. I also want to understand that garden, and recently I sought knowledge of the humble Zinnia. It’s an unassuming annual, that I have grown for years and often from seed. Likable for its late bloom in late summer — mid to late August — i.e. now. After most else has withered, here comes old dependable.
It turns out to be a Compound or Composite flower. It’s ‘a flower’ made up of many small flowers! What? Oh, there is that theme again: A ‘thing’ that is importantly many smaller things.
But what is more important, the Zinnia as a whole or as a simple aggregation? A pile of gravel is not an important development of the individual stones that make it up. You can double its size, cut it in half, throw in some sand; you can have the right side, I’ll take the left: Who cares? Can we say the same for the Zinnia? Is the whole Zinnia an important development of its pieces? Remember, that ‘one’ flower ‘is really’ ‘many’ flowers!
But Sheri sometimes says, “Shut up and just enjoy the Garden!” Maybe she is right, but, please follow me down this rabbit hole, even if for just a little.
How many flowers are there in a Zinnia? Well, first of all, botanists call the thing we call its flower “an inflorescence”; it’s the group of smaller flowers. To them, it’s important enough to have its own name for the various reasons we will discover.
In the inflorescence at right, there are at least 42 flowers, by my count! Each ‘petal’ is actually a modified flower; about 27 it seems. They are not true petals because true petals are a modified leaf in a Simple Flower, but not a compound one. Here, they are modified flowers called Ray Flowers, each with (some of, it varies) their own sexual equipment — pistil and stamen. In the Zinnia, though, these ray flowers are sterile, I believe; and each has for itself one large modified true petal that we see as the petal of the Zinnia, thought it is not; it is the ray flower’s petal. OK?
The other flowers that are obvious are the little yellow ones. There are 6 of these and they are called Disc Flowers. They actually look like flowers to us non-botanists and truly are. They have a full set of sexual equipment, fertile upon pollination, and produce one seed each in that case.
I am including about 9 other disc flowers in this above photo, those being the little white spots near the yellow. I believe they are soon to open or wilted ray flowers.
The Sunflower is also a composite flower. In this photo, if you look closely, you can see the wilted disc flowers (black) each on top of a developing single seed (green and domed) with ray petals at the edge.
But this is not all; 27 ray plus 15 disc equals 42 flowers in the inflorescence initially pictured. There are many more disc flowers though not evident in the Zinnia. A Shasta Daisy is also a compound flower and one with its disc flowers more evident. By my count (two tries) there are about 70 to 80 in this inflorescence at left. It doesn’t seem that many at a glance, but try for yourself; maybe I counted one twice! I did include about 15 on the perimeter as opened (thus indistinct in appearance) disc flowers.
Compounded Complications in the Composite
But the world of the Composite Flower gets even more complicated. Some compound flowers are all ray lowers and no disc flowers! As in the common Dandelion or Mum. Others are all disc flowers.
Even the Zinnia has a variety that is predominantly ray flower, the double bloom.
Returning to the theme of The One and The Many. A disc flower in a composite flower is not only distinct in appearance from a ray flower, but also has its time or order of opening determined by its place in the disc. Ray flowers open first, but then disc flowers develop from the perimeter of the disc moving to the middle. This is most elegantly displayed in some varieties of Sunflower.
(On left, the ray flowers opening on a new inflorescence of Zinnia. Right, the vague yellow circle within the disc of this Sunflower is the advancing blossom of disc flowers moving toward the center.)
That this Compound living together of the disc and ray flowers determines their maturation suggests a significant influence of the whole over its parts. All is not causation through time; some is definition of part in relation to part, as in any significant Structure. In other words, some is Participation not just causation. In the composite flower, flowers participate in their large aggregation as if by agreement, and thus become more than a mere pile. They become an entity with a significant unity that shapes their existence as individuals. They are a whole that is more than the sum of its parts taken individually.
More could be said about this unity of the many in the Zinnia and other composite flowers, but I do not believe it would enhance the case more than tax the reader. Enough said. Let us close with the following pictures.
The Garden as Metaphysical Instruction: the Zinnia as an Autonomous Structure.