A couple of weeks before my yard was colonized by mysterious pine-tree-like seedlings, something under the poison sumac caught my eye:
There, on the left. That green thing that looks suspiciously like a pine seedling. Immediately I had thoughts of another thing that looks suspiciously like a tiny pine. Childhood memories came percolating back of a diorama at the Smithsonian featuring a foot-long dragonfly and a bunch of symmetrical plastic plants. . .
This isn't a plant. It is called horsetail fern, or Equisetum arvense, and it is part of an ancient group of fern-like organisms that now primarily exist as the stuff that powers our computers and cars. Once upon a time these organisms grew to monstrous heights, and when they fell over into the swamp, there wasn't yet any creature there ready to digest them. So, there they lay in giant piles until they fossilized.
It's a pretty common plant. . . thing. Horsetail is native across almost all of the continental US, including Alaska, and it appears to be native on other continents as well. But common or not, I'm smitten with it.
(Update) Horsetails are mentioned in a Science Daily article about the diet of large dinosaurs:
"Horsetails were part of the sauropods' diet. For, according to research by the group, they are exceptionally nutritious. However, only a few animals feed off them today. A reason for this is presumably that horsetails are bad for the teeth. They contain a lot of silicate, which acts like sandpaper. But as long as you do not chew them but just pluck them and simply gulp them down, that is no big problem."