I’ll begin this long-promised post on the variety of color and form among our native iris with an exploration of the iris flower’s curious complexity. Here, for comparison, is the standard formula for how a flower is structured:
o Farthest from the flower’s center are the sepals, typically green and leaflike.
o Next toward the center are petals, the flower’s unabashed bid for attention.
o Next in, add a ring of stamens, bearing dust-like male pollen.
o In the center stands the female part, the pistil. Pollen grains, usually transported by insects, birds or wind, get deposited on the sticky cap, the stigma, and long pollen tubes grow down inside the pistil’s stalk, the style, to fertilize the flower’s eggs.
Now take a close-up look into an iris (above). Hard to fit to the standard model, isn’t it? First are three broad sepals, splendidly striped, and splashed with color. We call them falls, because they hold themselves out horizontally and bend gracefully downward at their tips. They’re landing pads for pollinators, conspicuously marked to guide arriving insects into the reproductive and nectar-producing parts of the flower.
Next are the three more-or-less upright petals–the standards–beautiful but far less assertive than the falls. They add a vertical dimension to the flower’s advertising.
Now look at the three bright, petal-like things that lie on top of the inner parts of the falls. Without a hand lens and a detailed knowledge of flower anatomy, you’d never guess what each is: a colorful, flattened, highly modified style! Underneath, the sticky stigma has become a simple cross-wise ridge that the pollinator has to squeeze itself under, scraping off the pollen it’s transported.
The stamens–the male parts, remember?–are snuggled, half-wrapped in the style’s folds. In the super close-up below, you can just glimpse the tips of the stamens, the anthers, loaded in this particular flower with royal purple pollen (in others it may be white or yellow).
So that’s how an iris’s beauty is assembled.
With that under our belt, let’s tour Marin, from Mount Burdell in the north, near the border with Sonoma, south to the Golden Gate Bridge, and from China Camp, on the silty eastward brink of San Pablo Bay, to Chimney Rock, far west at the end of Point Reyes.
The variety you see here from here on down the page–all from the last month and a half–is, as I said in February, the result of the complex hybridization Douglas Iris has done, uniquely in Marin, with Grass Iris (mostly around Inverness Ridge) and (strangely, because the species no longer occurs anywhere near Marin) with the pale Fernald’s Iris throughout much of the interior and eastern parts of the county.