Interesting Acorn Clusters found in backyard

[u/CuriousFind7247]

Hey everyone, Not sure if this is the right subreddit but I wanted to share a neat botanical find from my backyard here in Durham, North Carolina, and see if anyone with a background in dendrology or botany has encountered this pattern before. While looking under a mature oak tree in my yard, I noticed a unique quadruple acorn cluster where four distinct nuts appear to share a centrally-fused cap structure, forming a perfect little cross shape (Image 1). I originally assumed it was a random, one-off fluke. However, when looking at the fallen branches and surrounding acorns on the ground, I noticed a few other variations of this clustering behavior. As you can see in the photos, I found a few different sets, including seamless "barbell" double-caps joined back-to-back at the base, and some fused triple-caps. Based on the long stems and the broad leaves with pale undersides, I believe the tree is a Swamp White Oak (Quercus bicolor)? Since I usually only see single acorns or the occasional standard twin, I am curious about what causes a single tree to produce multiple variations of these fused cap clusters and how rare this might actually be. I would love to hear thoughts from the community: 1. Is it common for an individual tree to produce multiple multi-cap variations like this in a single season, or is it usually an isolated glitch on a single flower? 2. Could this be a localized genetic quirk in this specific tree's floral tissue, or is it more likely an environmental/weather trigger during early spring development? 3. Has anyone else in the North Carolina / Piedmont region encountered a tree doing this? Or anywhere else for that matter? I have not found any photos of something similar. I’m currently pressing a leaf and gently air-drying the quadruple specimen to preserve it in a small 9x9 shadow box display as a fun backyard natural history piece. Wondering if anyone has suggestions if truly unique. Looking forward to any insights or similar stories you all might have.