Whorlies (updated)

I don’t actually know all that much about plants. I took a number of biology courses in college and graduate school, but they were all in evolutionary theory or animal anatomy, with little or no botany. So all this work I’ve been doing lately on plant fossils from Beckley has had me scrambling through identification guides and paleobotany texts, and getting DB to sketch a lot of plant anatomy cross sections for me, to plug this glaring hole in my education. It also means that in many cases when I collect specimens from Beckley I have no idea what I’m looking at. Limited by my lack of detailed knowledge about plant anatomy and taxonomy, but still needing to sort specimens, we’ll sometimes use nicknames to talk about specimens, at least until we figure out what they are. That’s how we get names like “whorlies”.

The first whorlie we found is shown above. It was a curved structure, with radial ridges running across it. But what was it? Maybe some type of weird lycopod leaf scar, or a fern fiddlehead?

As we went through the early batches of the Beckley material we began finding quite a few whorlies. Here’s another one, not preserved quite as well:

We eventually ruled out fern fiddleheads, because some of the whorlies were actually more or less circular (the original arc-shaped one turned out to be incomplete). Eventually, by looking at lots of material, we found a specimen that gave us the answer:

It turns out the whorlies are the bases of cordaite leaves. In the image above, the whorlie is on the left, and the striated structure extending from it to the right is the leaf itself.

Cordaites are a group that are starting to become near and dear to my heart, probably because they don’t get as much attention as other Carboniferous plants like horsetails, lycopods, and ferns (I’m a sucker for neglected fossil groups). They were long-leafed cone-bearing gymnosperms that are only found in the Carboniferous and Permian. And I mean really long-leafed; a lot of the cordaites had leaves that approach 1 meter in length. It turns out that cordaites are one of the most common plants in the Beckley deposits:

Now that I know how to identify cordaite leaves, and know that the whorlies are part of them, I’m seeing them everywhere in these rocks. At this point it looks like they may be the second most common large plant in the deposit, after the lycopods.

Update: Many, perhaps most, of the whorlies, including the one shown above that I attributed to a cordaite, are most likely a branch attachment point on a horsetail. However, the morphologies are quite variable, and we don’t think all the whorlies are the same thing.

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2 Responses to Whorlies (updated)

  1. DB says:

    Working with you and helping is a great bit of fun. I must say, I learn more every time we speak! Thank you.

  2. Alton Dooley says:

    Likewise! It actually turns out that plants are really cool! Who knew?

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