Sample obtained from a rose in a flower bed at Caltech’s Moore Walk (Pasadena, CA) at 2:30 PM on 5 May 2019.

This rose (Rosa rubiginosa) pollen was rubbed directly onto the slide from the stamen of flower to collect the sample for viewing.

With a foldscope magnification of 140x with the image itself at 4x magnification, these images total to 560x magnification. Judging by the approximately 1 cm length of the grains in the image, we can conclude they are approximately 18-36 micrometers in length.

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