in Thoreau’s Journal:

The V. cucullata are large and conspicuous on Barrett’s side-hill. The ovata blue the ground in the Boulder Field. These and the pedata are all more or less lilac-colored, and it produces a pleasing bewilderment to pass from clump to clump, and one species to another, and say which is the most lilac. Putting one cluster beside another more lilac, the first no longer seems lilac at all. Has not violet then always some lilac in it?