Lucky to Be in Tulsa: The Twelfth Message from Fluff the Cottonwood Tree

 

I am happy that Stan has stayed in touch with me after he moved to France. He was glad to leave Tulsa, but I, speaking as a member of the species Populus deltoides, am lucky to be an American.

Almost everywhere in the world, mistletoes are parasitic. In Oklahoma, they grow mostly on elm trees, which are weakened by the Dutch Elm Disease. But in Europe, the elm trees (les ormes, Stan calls them) are stronger, and most of the mistletoes (gui, they are called) grow on black poplar trees (peupliers noirs, or Populus nigra). European black poplars are nearly identical to American cottonwoods, as I noted in my previous essay. If I had been a European cottonwood instead of an American, I would be loaded down with mistletoes. This photo that Stan took in December shows a typical black poplar.

European plant species are similar to, but usually not the same as, American plant species. But the ecological relationships—in this case, parasitism—do not always line up the same way. Evolution has played out along a slightly different path in Europe. Both America and Europe have elms, mistletoes, and cottonwoods, but in Europe it is the cottonwoods, more even than the elms, that are heavy with mistletoes. And in this one case, it has been good luck for me, an American cottonwood.

Similarities and Differences: The Tenth Message from Fluff the Cottonwood

Fluff the cottonwood here again. My ninth message was the most recent post. I just heard from Stan. He wanted me to tell all of you that he has now finished his permanent relocation to France. You will be hearing directly from him in the near future.

Since Stan is a botanist, one of the first things he did was to start learning European trees. He has not had much direct experience yet, as the leaves were falling when he arrived, and have now all fallen. But he wants to be ready for hiking in the mountains with his French family—the parents, uncles, and cousins on his son-in-law’s side—in the spring. And as usual for this blog he has a message about evolution.

In a photo book about French trees, Stan recognized most of the types of trees, such as maples (érables), alders (aulnes), birches (bouleaux), dogwoods (cornouillers), hornbeams (charmes), hazelnuts (noisetiers), chestnuts (châtagniers; European chestnuts did not die the way American ones did), oaks (chênes), beeches (hêtres), walnuts (noyers), ashes (frênes), sycamores (platanes), willows (saules), lindens (tilleuls), and elms (ormes). But in each case, the genera were the same but the species were different. This is because the deciduous forests of Europeand North America have been separate for millions of years, which sounds like a long time but is only long enough for new species to evolve within the genera that already existed.

The main one Stan told me about was the poplars (peupliers). Down by the river trail near his new apartment, he saw big trees that looked exactly like me. The leaves appeared to be just a little shorter and wider, but otherwise it was a cottonwood. Only in Europe it is called black poplar (peuplier noir). I am Populus deltoides; the European species is Populus nigra. The black poplar leaves look more like mine than do the leaves of another North American species, Populus fremontii, the Fremont cottonwood. I am more genetically related to the European species than I am to the species found in western North America.

Back in America, Stan would normally have launched into a speech about how this is evidence of each species having evolved in its own distinct location, rather than being the remnants of a Flood of Noah. But in France, nobody cares. There are essentially no creationists in France. There are no global warming deniers. Stan will discontinue a lot of what he was writing in America and focus on the positive and interesting things about evolution, botany, and science.