The sample was collected on May 9th, 2019, at 8:30pm from a California poppy (species: Eschscholzia California) just Northeast of the Olive Walk on Caltech’s campus (exact location: 34.136890, -118.122462). The sample was obtained by lightly brushing a few of the plant’s anthers against a clean glass slide until enough pollen had accumulated on the slide that we could actually see it. A clean cover slip was then placed over the pollen on the slide, and the slide was put into the Foldscope. A phone flashlight served as our external light source.
I believe the specs in the above image are grains of pollen. It was difficult to obtain an image of the entire field of view with my phone camera (as you can see in the above image only the center is in focus,) but when looking through the Foldscope directly, I counted approximately 120 grains of pollen.