
          I have not seen Koerber's work. When I was in London
in 1850 I asked Mr. [William] Pamplin to look out for everything
which appeared upon lichen and send it to me, but
I fancy he is not in the way of doing such thing -
and my library is deficient at present in several
of the new books. But the tendency of the new
school is not encouraging. There is no single author
of the standies of [Elias] Fries or Montague among them,
and they appear to be bringing the science back (by
a too great confidence in the microscopical apparent
differences, & the distinctions which they [assign?] to [?] on
these) to that chaos which Fries extricated it from 25
years ago. I am inclined therefore to extreme caution
in my studies of the microscopical structure, and to 
consider the characters derivable from it as always acquiring
a full support from all the other characters of the
plant. And this caution is the more important, doubtless
in myself, as I am not one of those who are naturally
inclined to investigations with the microscope.

I have just had a letter from Fries, & he expresses
an ardent desire to receive plants from California
and Oregon, and if you will send me such a collection
as you can spare of the species of those regions
and also of any of the extreme southern & southwestern states
        