I remember walking home from school once when I was in grammer school and seeing a collection of small( perhaps 1/4 size of a sesame seed), very round, tanish colored seed-like things scattered near a curb. The amazing thing was that they would pop up from the ground 2-4 inches with a little snapping sound. I also recall there being a tree near by. What did I see?
I’ve seen that, under trees and bushes in a park in California’s Central Valley in August.
My best guess is they were seeds with insect larva inside, who twitch and make the seeds hop, just like Mexican Jumping Beans. Next-best guess is that the natural seeds somehow have a mechanism to do this, but that seems far-fetched.
Where and what season did you see yours?
1/4 the size of a sesame seed is really small - could you please confirm that you really are talking about something a millimetre or so in size?
Yes. They definitely were smaller than a millimeter in diameter. Actually they were about the size of poppy seeds.
Cecil did a column on Mexican jumping beans: http://www.straightdope.com/columns/010803.html (halfway down). From there you can link to a page about jumping beans: http://waynesword.palomar.edu/plaug97.htm There you can read about jumping galls, which sound much like what you describe.
Thanks for the link Bibliophage. “jumping galls” are definitely what I saw. I was wrong: jumping galls average 1-1.5 mm–not less than 1mm.
Jeremy