these puff-Balls were growing on a log that had been submerged in the last lot of heavy rain.There were a couple of notable items of interest. There does not seem to be a specific point of rupture when the puffball matures. Some have ruptured at the outer edges and others somewhere in the top area. The surface of the top area was surprisingly rough to touch, and can be seen on the images with the pimple effect. I rolled one specimen over to show the underside. (4361) They did have a stem, although rather short, and when I pressed the ones that had already opened, they discharged a mustard coloured dust.