Thoreau writes in his journal:
P. M.—To Hubbard’s Close Swamp.
The vetch just out by Turnpike,—dark violet-purple. Horse-radish fully out (some time). The great ferns are already two or three feet high in Hubbard’s shady swamp. The clintonia is abundant there along by the foot of the hill, and in its prime. Look there for its berries. Commonly four leaves there, with an obtuse point,—the lady’s-slipper leaf not so rich, dark green and smooth, having several channels. The bullfrog now begins to be heard at night regularly; has taken the place of the hylodes.