My wildlife post: the mystery plant

Two days ago I posted a photo of this mysterious and scary-looking object that I found on the trunk of my car:

I asked readers to identify it, and they weighed in yesterday. The consensus seemed to be that it was a seed pod from a Turkish Hazel tree, Corylus colurna (also called the Turkish Filbert), and certainly did not come from the tree that hung over my car—probably a black locust, which produces a legume pod that looks nothing like the above.

To solve this mystery, I inspected the trees and ground around my car, which I hadn’t moved since the triffid pod appeared on its trunk.  First, here is my car in situ (far side of the road second car from the left). Every one of the three trees you can see are locust trees, so the pod could not have fallen from one of them.

Nevertheless, the ground under the locust tree next to my car (and the one behind it) was littered with dried pods. See them?


The underside of the pod, showing the seeds. They look like hazelnuts to me.

And the two trees across the street from my car. This one looks like an oak (remember, I am a “fly guy,” not a botanist):

And the leaves of the other (you can see my car at upper left). I couldn’t get a better shot as the wind was blowing hard and the leaves out of reach.

Now the leaves of that tree sort of look like those of the Turkish hazel, as do the seed pods, as shown in this photo from Wikipedia, but the shape isn’t exactly the same. But of course leaf shape can vary depending on the local environment, sun, and other factors:

So this may be a Turkish hazel, which readers have found is a tree planted along Chicago streets. If it’s not, perhaps it’s a relative.

The only remaining mystery is this: why were the pods found only underneath locust trees across the street? I found NO pods underneath the putative Turkish hazel or oak.  One answer may be that the squirrels took the pods tree across the street to eat the nuts (or cache them)—but why would they do that? Or the pods underneath the locusts could have been blown across the street, or fallen from the tree across the street. That doesn’t make sense, either given the absence of pods under the putative source tree.

I will refrain from further comment, as I have no solution. If readers want a better picture of the putative hazel tree, let me know.



  1. ThyroidPlanet
    Posted August 8, 2017 at 7:41 am | Permalink


  2. GBJames
    Posted August 8, 2017 at 7:43 am | Permalink

    The putative hazel tree photo doesn’t look like a match to me, but it is kind of blurry so….?

    Are there any of the “mysterious and scary-looking objects” hanging from any tree branches?

  3. Bob Scott Placier
    Posted August 8, 2017 at 7:57 am | Permalink

    The second tree is not a hazel, but a maple (Acer spp.). You can clearly see the opposite branching. Hazels are in the Corylaceae (or Betulaceae) family, all species of which have alternate leaves. So the mystery continues, but the fruit (nuts) are definitely a hazel (Corylus) species.

    • Posted August 8, 2017 at 9:21 pm | Permalink

      I concur.
      I think the mystery stash could be due to squirrel activity or perhaps someone collected a bunch of the hazel nuts and abandoned them.

    • Posted August 9, 2017 at 8:45 pm | Permalink

      I wish I could see the trunk more clearly just to make sure it’s a maple and not a sycamore.

  4. Posted August 8, 2017 at 7:58 am | Permalink

    There can be only one answer.


    • GBJames
      Posted August 8, 2017 at 8:02 am | Permalink

      I’ve heard He spreads pods in mysterious ways.

      Have you not noticed? “God” and “pod” differ only by one letter!

      • Posted August 8, 2017 at 9:16 am | Permalink

        Pod moves in mysterious ways.

        • Posted August 8, 2017 at 11:40 am | Permalink

          Now we’re *really* going all out _Day of the Triffids_, no?

  5. Posted August 8, 2017 at 8:00 am | Permalink


  6. Posted August 8, 2017 at 8:00 am | Permalink

    The putative ‘hazel’ tree is some kind of Maple and not the source of the seed pod. So? Maybe squirrels had a party or maybe a child gathered a bunch of the hazel pods to take home and plant or eat and he dropped them there. Also maybe,the Turkish Hazel can also grow as a bush so might be less obvious along the street but in s garden.

  7. Terry Sheldon
    Posted August 8, 2017 at 8:02 am | Permalink

    The first tree across the street is a silver maple (Acer saccharinum). The second one I’m not as sure about. It could be either a Norway maple (Acer platanoides) or sugar maple (Acer saccharum) but is probably the former. None of those trees produce seeds that even remotely resemble the hazelnut pod.

    • Reginald Selkirk
      Posted August 8, 2017 at 8:47 am | Permalink

      I concur. The first tree is Silver Maple, and the second one is Norway Maple or Sugar Maple.

      • Posted August 8, 2017 at 9:33 am | Permalink

        Yes, did not look carefully enough-not an oak and most likely a silver maple. Got oaks on the brain these days.

  8. Liz
    Posted August 8, 2017 at 8:10 am | Permalink

    Probably the squirrels.

    • Ken Phelps
      Posted August 8, 2017 at 10:19 am | Permalink

      Of course it’s the squirrels.
      They’re everywhere.
      They can’t be trusted.

  9. Posted August 8, 2017 at 8:12 am | Permalink

    Is it possible the pods are designed to roll along the ground during a windy day?

  10. aea
    Posted August 8, 2017 at 8:15 am | Permalink

    yesterday’s leaf is from a honey locust, not a black locust. super common street tree in chicago. all over hyde park and campus.

    the leaves from today are silvr maple and maple.

    the turkish hazelnut/filbert is definitely planted on campus and in HP residences and that is its characteristic seed pod.

    I’ve seen them at drexel and 56th, and it appears the tree inventory shows that AND at the place you found them as well

    and yes, squirrels often process their food in a place other than where they picked it up!

  11. Posted August 8, 2017 at 8:15 am | Permalink

    I have a hypothesis. Somewhere around the adjacent tennis court grows a Corylus Colurna. Seeds from this tree littered the tennis court prompting would-be tennis players to sweep the court. They swept the seeds to the nearest street, which happens to be where you are parked.

  12. GBJames
    Posted August 8, 2017 at 8:22 am | Permalink

    I’d like to put in a request for a link to a Google map of the location where the PCC-mobile is parked in the photo.

    • GBJames
      Posted August 8, 2017 at 10:10 am | Permalink

      I was hoping you didn’t park in front of where you live. I do understand why you wouldn’t want your address known.

    • David Duncan
      Posted August 8, 2017 at 11:14 am | Permalink

      Didn’t the university give you an under cover spot in a garage as part of your retirement package?

  13. Posted August 8, 2017 at 8:28 am | Permalink

    Or you could call the city parks dept. and ask where they have planted turkish hazel?. Better use the latin name tho’
    You are correct about the ‘oak’ tho’ I don’t know which species, other than some kind of red oak.

    • Posted August 8, 2017 at 8:36 am | Permalink

      No, that is a maple, as is the other tree in today’s photos. They are NOT hazelnut trees. As you can see in Jerry’s Hazelnut tree photo from Wikipedia, hazelnuts have alternate leaves, while maples have opposite leaves (leaves in pairs). This is one of the first traits that a botanist checks when facing a tree ID. The second maple in particular shows the opposite (paired) branching pattern.

      • Posted August 8, 2017 at 9:37 am | Permalink

        Yes, thank you. That is a maple. I did not look carefully enough.

  14. Simon Hayward
    Posted August 8, 2017 at 8:37 am | Permalink

    I don’t know any “why did the squirrel cross the road” jokes

    • Posted August 8, 2017 at 8:44 am | Permalink

      Where I live, the joke might be:

      Q: Why did the squirrel cross the road?

      A: He didn’t. He made it only half way.

    • Torbjörn Larsson
      Posted August 8, 2017 at 4:26 pm | Permalink

      Because the city had an alternate-side park rule?

  15. Reginald Selkirk
    Posted August 8, 2017 at 8:56 am | Permalink

    The third picture:

    Identifying Norway Maple and Sugar Maple Trees

    The two are superficially similar, but you can tell them apart by checking a few details. My first guess is Norway Maple, but try this:

    “During the growing season, Norway maple leaves are unique in that a milky fluid is seen when their petiole is removed from the stem.”

    Or maybe you don’t care, since neither one bears hazelnuts.

    • Reginald Selkirk
      Posted August 8, 2017 at 8:59 am | Permalink

      Another clue: the black spots on the leaves. Norway Maples are suffering a lot of that this summer due to the weather conditions.

    • Reginald Selkirk
      Posted August 8, 2017 at 9:00 am | Permalink

      Sorry, that’s not the third picture, but the penultimate picture.

    • Terry Sheldon
      Posted August 8, 2017 at 9:29 am | Permalink

      I agree that it is probably a Norway maple, but with overlapping leaves it’s a little hard to distinguish which lobes belong to which leaves in the photograph.

  16. Reginald Selkirk
    Posted August 8, 2017 at 9:03 am | Permalink

    The creationists would have a good laugh if they found out a vaunted evolution expert can’t identify some of the most common trees.

    • Ken Phelps
      Posted August 8, 2017 at 10:28 am | Permalink

      Of course they would. In their world, where an engineer can fully understand evolutionary biology and cause the entire edifice to crumble with a single penetrating thermodynamic insight, what’s to know except the taxonomy of your neighborhood?

  17. Reginald Selkirk
    Posted August 8, 2017 at 9:05 am | Permalink

    “Man who leaves peanuts on his window sill astonished that squirrel food may get moved from place to place”

  18. Posted August 8, 2017 at 9:16 am | Permalink

    Filbert = hazelnut

  19. Posted August 8, 2017 at 9:33 am | Permalink

    Look for shrubs. The hazelnut can be a shrub. If there are no hazelnut shrubs, that “sweeping the tennis courts” hypothesis sounds plausible, and testable.

  20. Reginald Selkirk
    Posted August 8, 2017 at 10:10 am | Permalink

    Meanwhile, in suburban Chicago:
    Hazelnut Fest expands to 3 days
    Hazel Crest is returning its Hazelnut Festival to three days, officials said.
    The festival will be Aug. 4-6 at the Hazel Crest village grounds, 3000 W. 170th Place.

    That’s only about 16 km from you. Perhaps someone attended Hazelnut Fest and swept out their car afterwards.

  21. Randy schenck
    Posted August 8, 2017 at 10:13 am | Permalink

    You should probably stop parking that classic car out there on the mean streets. Who knows what will fall on it next.

  22. Gregory Kusnick
    Posted August 8, 2017 at 10:39 am | Permalink

    Another hypothesis: buses, landscaping trucks, delivery vans, and other large, flat-roofed vehicles that make frequent stops act as vectors for the dispersal of fallen pods throughout the city.

  23. Diana MacPherson
    Posted August 8, 2017 at 11:47 am | Permalink

    The only remaining mystery is this: why were the pods found only underneath locust trees across the street?

    Because it’s a message. The squirrels set that there as a warning. Feed us the GOOD seeds or else!

  24. Posted August 8, 2017 at 12:14 pm | Permalink

    Got to be careful about making conclusions based upon small data sets. Could the aerodynamics of those seed pods come into play? I have no idea of their mass but if the wind were blowing one direction one day (sweeping all of the pods off thataway) and then shifted to the opposite direction, that seed pod could have come over the roof from the next street over quite easily.

    Religious answers are so much easier–“Ah, it is a mystery, my son.”

  25. Posted August 8, 2017 at 12:39 pm | Permalink

    My neighbor had a large hazelnut tree. Every year the jays and squirrels would bring many of them into my yard. You could watch them going back and forth and back and forth.

    Maybe if you looked for a hazelnut nearby or watched for squirrels and jays you could find the source.

  26. Mark R.
    Posted August 8, 2017 at 1:25 pm | Permalink

    2000 Civic with 74,000 miles? That’s only 4,352 miles a year and I bet a huge chunk of those miles came from your Reader road trip. Obviously, Chicago is a walking town; I imagine it has decent city transit as well.

    I have to drive 24 miles round-trip just to go the grocery store.

  27. Posted August 8, 2017 at 2:42 pm | Permalink

    Whatever you do, don’t fall asleep next to one of those pods!

  28. rickflick
    Posted August 8, 2017 at 8:11 pm | Permalink

    FWIW, I’ve recently come across this tree identification site – leafsnap.
    I haven’t used it much so I don’t know how good it is. A search on hazelnut failed. It’s listed as Turkish Filbert or Corylus colurna in the table. One nice thing about it is it includes an image of the tree’s bark which is often very helpful in tree id.

  29. infiniteimprobabilit
    Posted August 8, 2017 at 8:56 pm | Permalink

    Or, some student prankster put the pod there and is cracking up reading this discussion…

    (I know that’s a bit like resorting to ‘Goddidit’ but I suppose it’s a possibility. To quote Sherlock, When you have eliminated all other possibilities…
    Has one big advantage over Goddidit, students exist).


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