The Largest Acorn

Crack open your field guides!

Today’s quiz is:  Identify this enormous acorn.

Here are some of its characteristics:

  • The acorns are huge, the largest acorns native to North America.  The cups measure 1.25″ across.
  • The outside has a rough diamond pattern with a fringe at the edge.
  • The inside of the cup is smooth.
  • The acorn itself is dark brown at this time of year (see last photo).
  • This oak is in the white oak family.
  • I found them in Schenley Park.

Here’s a close-up of the cups…

…and an acorn inside the cup.

Do you know what species this is?

Leave a comment with your answer.

UPDATE: The answer is bur oak, aka mossy-cup oak (Quercus macrocarpa).

(photos by Kate St. John)

14 thoughts on “The Largest Acorn

  1. Burr Oak? Mossycup Oak? (I think it’s the same thing w 2 names) I’ve seen these used in wreaths and other fall decorations

  2. My research indicates that this is a bur oak (Quercus macrocarpa). I’ll have to keep an eye out for these….I don’t think I’ve ever seen them in person. I am still not good at identifying trees (especially varieties of a particular type of tree)…sycamores and tulip trees are easy, identifying an individual oak type, not so much.

  3. Quercus macrocarpa

    Bur oak, aka mossy-cup oak

    It withstands harsh conditions and is one of the most drought resistant oaks.

  4. Sharon…I had to go and look at my wreath…and you are right. There are 5 of them on it! Wish I could take credit for the wreath, but I bought it at a craft show!

  5. bur oak….bet the squirrels and chipmunks get a cheekful of these…I think they grow on Penn View…I have never seen these, but bet they would be cool in arrangements…

    1. I forgot to mention that Burr Oaks are often cultivated. That’s why this one is in Schenley Park.

  6. Looks like Quercus macrocarpa
    The Bur Oak has the largest acorn of all Oaks that are found in the U.S. They love Prairies and savannahs and can survive prescribed burnings. A magnificent tree from the white oak sub group.

  7. There is a huge Bur Oak yielding identical acorns and husks near downtown Houston near the intersection of Caroline Street and Binz Street. It is thriving in a narrow strip of City-owned easement alongside the Caroline Street curb and sidewalk. While visiting a friend’s home recently, we discovered the tree’s acorns and brought one with us to ask others at his residence to identify it. Luckily, a horticulturalist was also present at our friend’s party and he quickly solved the riddle. If this acorn is low in tannin, then some entrepreneur could get rich harvesting this tree’s produce! Its acorns are golf ball size and very pleasing to the eyes!

  8. Bur Oak – we have about 7 of these trees on our property and many more in the surrounding area. Squirrels love the acorns, but I’ve also watched deer eat them.

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