This is brand new Tulip tree (Liriodendron tulipifera) leaf, pinky-nail-sized, still to unfold into its characteristic mitten-like shape. That was the extent of early spring growth on these giants of our forest one weeks ago, so when I noticed a patch of rich green way up on a branch of a mature specimen of this species:I wondered what it could be. Because it was so high, this is the best picture I could manage. In the binoculars, this looked small-leaved, not unlike parsley. Any idea what it might be?
(For possible answers, check out the comments below.)