The summer aspect of the river begins perhaps when the Utricularia vulgaris is first seen on the surface, as yesterday. As I go along the railroad causeway, I see, in the cultivated grounds, a lark flashing his white tail, and showing his handsome yellow breast . . .

  7 P.M. Up Assabet.

  The tupelo’s stamens are loose and will perhaps shed pollen to-morrow or next day. It is twilight, and the river is covered with that dusty lint, as was the water next the shore at Walden this afternoon . . .