I noticed in HD’s blog (his journal now online — here: http://blogthoreau.blogspot.com/) that he refered to ‘lettuce Lichen’ on January 8th, 1857.
I wonder if its the same lichen that Peter Severence pointed out to us on our walk in Graniteville Woods last fall. Peter told us that it was edible if boiled twice. I sent Peter a message asking him about it.
In any case the lichen is doing well this year, benefiting from wet and warm weather.
Here is what Henry wrote about the Lichen:
“I perceive that the livid lettuce-leaved lichen which I gathered the other day has dried almost an ash or satin, with no green about it,—has bleached.”
The lichen I see does look like lettuce and does dry out once plucked. I posted the photos you see here to give you a chance to opine as to whether this is Thoreau’s lichen or not. I like to think it is.