Abortive Suckers: The Mystery of the Cypress Knees

I had never seen or heard of cypress knees before last year, when I visited Spring Grove Cemetery in Cincinnati. It’s a beautiful place to walk around. The landscape is idyllic. Grass, grass, trees, trees, pond, swans, mausoleum, leaves, tombstone, tre—what the hell are those?

MICHAEL: We don’t know where it came from, how long it will last, or what caused it. Janet, what do we know?

JANET: We do know where it happened: here.

This is a quote from The Good Place. It could also be the sum total of scientific information on cypress knees.

I am exaggerating, but only a little. Nearly every article I’ve read on these marvelous knobby protuberances uses the word “mystery,” even the articles purporting to know what cypress knees even are, what they do, and why they exist. We know that some species of cypress trees produce these knees, and that they’re made of bark-covered lumps of tree. We know they’re more common in low-lying areas near ponds and swamps. Some scientists posit that they help the tree with gas exchange. Others disagree. Most just shrug.

The most commonly cited work on the subject is “Cypress Knees: An Enduring Enigma,” published in the journal of the Harvard Arboretum in 2001. The second-most-cited work is from 1952, and there’s not a ton in between. One of the top results in my literature search was a chapter from a book called Real-Life X-Files: Investigating the Paranormal. I am not making this up.

This passage from an 1888 article might be my favorite find:

Nothing but shrewd guesses have been offered in explanation of the habit the Taxodizum has, of throwing up the excrescences known as ‘Cypress Knees.’ The generally accepted guess is that they serve to supply the submerged roots with air, but just how this tough woody tissue can act in this manner is not clear to the vegetable physiologist. This guess was in a measure supported by the statement that the tree produced knees only when in very swampy ground. I once believed this, but recently an instance came before me where on a dry bank, though near a lake, the knees were abundant.

I have seen them in dry places in Mississippi and Louisiana, but I fancied the situations were once wet, when the knees were first formed. A writer in an English horticultural journal hazards a wholly novel guess that they are abortive suckers, and in support of this states that a tap-root is always found beneath a knee. This last statement of fact is wholly new to me.

The knees were abundant! The situations were once wet!

I contacted the author of the 2001 article to see if he’d be willing to answer a few questions. To my delight, he agreed immediately, while admitting that he might not have much information to share. Then I sent him my questions. I never heard from him again.

That was enough of a sign for me. It was time to stop digging.

To someone like me who likes to learn everything about everything, The Case of the Mysterious Cypress Knees could feel unsatisfying, like a frustrating dead end. Instead, this apparent gap in our collective knowledge feels like a wink and a prize: a reminder that this world is positively rooted, knotted, and kneed with mysteries, sprouting right up from the ground.

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Top image: still from the trailer for The Beast from 20,000 Fathoms via YouTube. The tree knees are mine.