Evolution Two-step

In fond hope of luring pipevine swallowtails to my yard, I planted a native Aristolochia, a Dutchman’s pipe, a few years ago. After a sulky adolescence, it has climbed the fence support and is fighting it out with the ‘Roger’s Red’ grape. It looks like a plant with a will to clamber, even to produce flowers now and then. The flowers won’t lure the butterflies — it’s a caterpillar plant for them — but they’re a mark of peculiar ancestry. The plant is part of the Magnoliids’ branch of the Tree of Life, which particularized itself from other flowering plants early in their history, even before the monocots and dicots (lately called “Eudicots”) set off in their different directions. Or so some of the storytellers allege.
The story keeps changing in interesting ways. As researchers cook up new experiments and unravel the genetic knots that form individuals and cultivars and races and species, they find some odd connections and routes of ancestry. In the process, the public gets to learn lots of those little facts that twist one’s perspective delightfully. Did you think mushrooms were plants, sort of? So did I, but look: They have cell walls like plants’, but the walls are composed not of cellulose but of chitin, like a shrimp’s shell. If I were a hyperscrupulous vegetarian, I might be watching the science news nervously.
In the garden, I delight to find myself in the company of some pre-dinosaurian ancients like the ferns under the redwood. Probably because the first creation story I ever heard was Genesis, it jars a certain sense of order in the back of my brain to think of any of my flowering plants as being of younger lineage than any animals, more different from the conifers and other gymnosperms than the salamander under the old tub is from whatever swam here in the Devonian. But I should be used to that little sidewise jump in the course of thought, as it happens regularly. I remember being surprised, for example, to realize that monocots diverged from dicots, not the other way ’round, so that irises and lilies and all the myriad grains and grasses are more recent an idea than, say, lotuses. It wasn’t all that long ago that monocots were being called “primitive” ancestral plants. Sometimes the smallest new detail changes the whole outline of the story.
Of the three oldest lineages of flowering plants, one is found in the pond, one in the pantry, and one on a South Pacific island. That water lily antedates a lot more than plumbing, and the star anise on the spice shelf could have seasoned a dinosaur steak. Outside of New Caledonia, the best place to find the humble shrub Amborella would be UC Santa Cruz, and I’m sure the bush there is in seclusion and not granting interviews since it was nominated as an example of Earth’s first flowering plant. There’s another counterintuitive fact — evidently plants thought of wood before they thought of flowers. The progression doesn’t go from creeping herb to mighty tree at all.
Of course not; it isn’t a progression. It’s a branching-out, a convoluted and meandering dance. Plants and animals two-step and do-si-do with each other constantly, and I in my garden am in the midst of it, along with the birds eating fruit and dropping seeds in conveniently fertilized packages, the leaves nourishing caterpillars who will grow up to pollinate the flowers, the bees storing honey to be taxed by the humans who will move them to whole new continents. Plants have been using us well, particularly since they began flowering. It’s not just the blossoms, dazzling and compelling as they are; what draws us to move plants great distances and care for them well is usually that tasty, nourishing, and incredibly various pericarp, the fruit that surrounds the missionary seed.
When you start to feel that — even aside from the birds and the bees — you aren’t alone in your garden, there’s another perspective shift. Humans are questioning plants in ever-new ways, looking the potato in the eye and closer yet, reading flowers and cells and molecules for hints at the shape of the connection — more obvious every time we look — that we share with all life. It’s not a fable or a metaphor: We are physically related, we are one with all life. As we peer through that scanning microscope, everything else on earth is looking over our shoulders.
What is it they want us to find out and tell aloud?

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