Observations by erinma

Leaves have purple undersides.

iNaturalist suggesting columbine family?

Very hairy. Undersides of leaves are purplish.

Growing on the leaves of an American Sycamore tree

Growing on fallen branches of a Sycamore tree

Basal leaves, growing out of a crack in a stone wall. Hairy, undersides purple.

Upper side of leaves sandpaper-rough to the touch

Growing on the bark of a mulberry tree

iNaturalist suggests this is a Sundrop or Primrose. Any ideas?

I think this is a black knot of a black cherry tree.