Mystifying Mushrooms

Photo date: October 5, 2015. Photographer: Mark Mahin.

The photo below was taken while photographing ordinary drops of pure, clean water falling against a dark featureless background.  We see on the right two more examples of the "orb mushrooms" I have recently started to find in my photos of falling water drops. See here for more examples.

Here is another example of two of these "orb mushrooms."