in Thoreau’s Journal:

A still afternoon with a prospect of a shower in the west. The immediate edge of the river is for the most part respected by the mowers, and many wild plants there escape from year to year, being too coarse for hay. The prevailing flowers now along the river are the mikania, polygonums, trumpet-weed, cardinal, arrow- head, Chelone glabra [white turtlehead] and here and there vernonia. The button-bush is out of bloom and its balls browning.  On the steep hillside where the Leaning Hemlocks grow slanted over the river and from year to year falling into it, I am surprised to see that many are leaning and falling up the hill, owing to a slide which has carried their roots forward toward the water. I hear the muttering of thunder and the first drops dimple the river.