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Hi all,
I wonder if anyone might be able to help with this seed ID or point me in the right direction. This seed is from the La Brea Tar Pits in Los Angeles, California. It may be modern or fossil, it’s hard to say without dating it. But it has us stumped as far as ID, we thought it might be Rubiaceae at first, but I’m not sure that’s right.
Its round/oval in shape and 2.08 mm at it’s longest point.
Hello Jessie,
I can see how it this seed looks similar to Galium or other Rubiaceae species. The button shaped features on either side of the seed will be key I think.
About other plant remains found in the same area/ layer – Would they indicate an environment similar to modern, or were wet-costal or subtropical species found as well?
Thank you, Jennifer
Hi Jennifer!
They’re all species generally found along coastal California today. That button was definitely throwing me off. I haven’t been able to find a family with a similar feature.
Thank you for your help!
Hello again,
From what I could find so far, Musaceae, Zingiberaceae, and Myrtaceae species have seeds with a central, button-like hilum. Commelinaceae does as well (the ‘button’ is a lid over the embryo, an embryotega). The linear hilum in this family is on the opposite side like in your seed, but I don’t think it opens up like in the image. I was wondering if it’s a fruit, but it may be too small. I’ll keep looking.
Have you seen any plant matter be preserved in the Tar Pits? How about insect egg cases?
Does the tar stain the material a blackish colour? Does it tend to distort seeds/ fruits?
One more question – could you tell us a bit about your project in the Tar Pits? 🙂
Thank you, Jennifer
Thank you so much for your help! Those families would be a bit of a surprise, but I’m truly stuck on this one (I was hoping it was something obvious I was missing).
We have a lot of plant matter! We have wood, seeds, cones, (some) leaves, as well as phytoliths and pollen. We’re working on identifying and radiocarbon dating the plants so that we have a timeline of vegetation for the Tar Pits. The majority of it is very similar to Southern and central california today. We only have one species of juniper that can’t be found currently in california.
As far as color, it varies depending on material being preserved, but generally the asphalt gives all our fossils (and modern contaminants) a brown color. There isn’t any physical changes from the asphalt alone, there may be wear and smushing (technical term) from processes occurring before or after deposition. But a lot of our material is in amazing condition.
I have come across a number of these specimens in older deposits (~45 ka) and they don’t seem to have much variability in size and shape. The timeframe places them in communities that appear more similar to the Central California Coast today (coastal closed cone pine forests).
I know it’s not a lot to go off of, but I really appreciate your time any insight you have into this mystery.
Good morning,
That’s a really interesting project, thank you for sharing a bit about it. The additional information is great – it gives context about the environment these seeds were found in. Did you mention there were more of these found? If so, some group images with more seeds would be great to see.
Thank you, Jennifer
ETA: I’m now wondering about an immature oak tree seed, or even female flowers? There’s an image of a Coast live oak female flower on this webpage: https://friendsofedgewood.org/coast-live-oak
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Here’s some top bottom and side views. Except for that one squished one, the walls of them seem relatively substantial. You can see some openings in a couple of them.
In the baby oaks I’ve seen you can usually make out the scales of the cupule forming and the pistil is very obvious. I’ll have to take closer look at the female flowers!
Hello Jessie,
The additional group pictures are great, thank you! I am still looking for some seeds or fruits that look similar to the images.
Could you let me know what other plant species (seeds, fruits or vegetative parts) have been identified from the same layer? I am hoping some more context might provide more clues (or deepen the mystery).
Thank you, Jennifer
Hi Jennifer,
Thank you for all your help with this.
Generally, we’re finding bishop pine, monterey pine, monterey cypress, manzanita species, juniper, oak, and chamise. It’s hard to say what existed together (we don’t have stratigraphy), but they are all broadly found in the same period of time.
Hi Jessie,
Thank you for the information, I wondered if there were traditional ‘layers’ like in other branches of archaeology. I imagine there would be a bit of mixing in those pits over 1000’s of years!
What about berries of Phoradendron (leafy mistletoe)? I’m not sure if the base has that unique ‘button’, but they do have a slit-like or 3-parted structure at one end. The image of P. californicum at the top of the Wikipedia page for Phoradendron caught my eye. What do you think?
Thanks, Jennifer
The more I look at Commelinaceae the more I’m convinced it’s something in this family, a Tradescantia or Commelina maybe.
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