This nasty little sticker ball is surrounding those chestnuts that they'll sing about roasting on an open fire in a few months. Do people actually roast chestnuts? Anyway, my next door neighbor has a large old American Chestnut tree in her back yard. The tennis ball sized stickers drop to the ground and open into four wedges releasing the nuts inside. The thorns are very sharp and quite effective at protecting the nuts. Canon 40D, 1/250 sec @ f/11.0, ISO 400, 50mm macro lens with off camera flash at 1/64th power.