Answer
This is a basswood seedling showing normal development pattern for the species. The palmate leaves are actually cotyledons, or “seed leaves,” that helped to nourish the seedling while its first true leaf (the dark leaf in the center) developed. As noted in this post from the Finger Lakes Native Plant Society, “The cotyledons of basswoods look nothing like their adult foliage. The two cotyledons are deeply palmately divided, and carpet the forest floor in spring.”
This week’s contest winner was Seri Lowell