Easy to miss, the spore case has whitish rough surface, about 2 cm across. There are 9 rays that open, they're cracked but become smooth with water. I drizzled water on it and the rays spread wide open within minutes. Cocoa brown spores inside the sack. Hard to see in the photo, but some of the spore powder is at the opening too. Pretty cool.
Sandy dry open shrubby area of the North 40 at Floyd Bennett Field in Brooklyn.
Hygroscopic is my new mycovocab word in which the rays open up when wet with water (presumably rainwater).