in Thoreau’s Journal:

I am going in search of the Azalea Nudiflora….

The fact that a rare & beautiful flower which we never saw–perhaps never heard for which therefore there was no place in our thoughts may at length be found in our immediate neighborhood, is very suggestive.

[Very long passage follows about this search. To my reading Thoreau’s jury was out as to whether he eventually found Azalea Nudiflora. The photo attached is of what I imagine he saw as it blooms prolifically now in exactly the types of locations he describes in this passage.]