This Puffball, Lycoperdon marginatum, can be told from Lycoperdon perlatum by its rounder (not pear-shaped) form. These measured around 2 cm. They can sometimes be flattened on top (see the second-to-last photo) and often develop a pinched base, which you can see in the last picture, somewhat. These lacked the "whitish warts about 2 mm high" (Mushrooms of the Midwest, p. 266), but some that I found a couple days prior did. What's left here are some tiny brown patches. These were growing beneath Oak and Hickory.