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

Recently I was laying in a grassy field near Princeton University when I got a terrible itch. A few blades of grass crept up my pant leg, one of them covered in seeds. The seeds rubbed off on my ankle, and the tiny prickles made the area irritated. I wanted to take a closer look at the seed structure to see what, exactly, was making me itch. So I took it under the foldscope. With the foldscope I could see how the seed structure split into fragments. I think the fragmentation and the points were irritating my skin. Though I couldn't get a clear photo of it, there were also small, spiky structures at the tips of the seeds. I wonder if these spikes make the seeds extra sticky on skin and fur? Could they be structures to facilitate seed dispersal? I've studied a bit about seed dispersal before, but only much more extreme examples, like stickers and burrs. It's hard for me to tell what selective pressure, if any, would drive the grass to this shape.

I would also love to splice the seeds more as well. I'm curious to know if these spiky structures on the tips are made of specialized cells. You can see the plant cells from the base of the seed in the photo I provided, but I'd like to investigate if cell shapes differ along the seed. If they do (which, based on my preliminary look, they seem to), then how do plants produce cells with different shapes to produce these sharp structures? Are these cells specialized, or just varied in shape?

I tried to identify the grass using iNaturalist and Seek, but I could not get a reliable answer. If anyone can identify this grass, please let me know!