Wandering around Princeton University with Foldscope in hand, Sanjay and I began our search for something interesting and unique to examine with our new instrument. We made our way to the south side of the Frick Chemistry Lab Building, curious since we had never seen that side of the building before. Once there, we found this impressive tree that we believe to be a birch standing alone in a clearing:

We first scanned the tree trunk, peeking into every crack and crevice looking for something to study. We were disappointed to find only dead leaves and standing water, so we extended our search to the tree’s branches. Looking at the tree’s extremities proved rewarding, as we were excited to find this isolated patch of rust-colored fungus:

We promptly took samples of the fungus and made slides for our Foldscope. The fungus itself raised plenty of questions on its own. Why was the population so isolated on that branch, and specifically in that spot? We began to think about the conditions and resources required for the fungus to grow there. Maybe it had to do with sunlight availability, as the branch we found the sample on was very low to the ground. The coloration was another important area of concern for us. Is it a warning mechanism for potential predators? If that is the case, is the fungus actually poisonous?
Obviously, the Foldscope alone cannot answer many of these questions. But it can allow us to understand the relationship between the tree branch and the fungus, and raised many more questions on its own. One of the first things Sanjay and I looked at was the interaction between the tree and fungus.

The Foldscope allowed us to gain some interesting insight into the tree/fungus relationship. What we can’t see at the macroscopic level is how exactly the fungus latches onto the tree bark so that it is not swept away by wind and rain. What the above picture shows is almost a vein-like structure to the tree bark as the fungus surrounds it. We believe that this picture indicates an anchoring process by which the fungus roots itself into the branch. This discovery raises further questions about the exact mechanism the fungus uses to embed itself: does the fungus grow on top of the branch, then burrow into it for stabilization? Or maybe it grows outward after initially breaching the bark. These questions warrant further study, and could provide opportunities for further observational and experimental research.

Sanjay and I conducted this project as part of Professor Pringle’s EEB321 class at Princeton University.