
          St Louis May 13th 1845

My Dear Sir

I am much obliged to you for
offering me an opportunity to get acquainted with
so zealous naturalists as your young friends appear
to be. They staid here longer than they anticipated,
and I had an opportunity to see them often; we
also made a few botanical excoursions together, and
collected the few early varieties here abouts. You will
probably have learnt from them that they intend to
extent their trip to the shores of the pacific and
to California. If their luck is equal to their
zeal and their confidence, they will bring back rich
treasures.

My best thanks also for the interesting parcel of
pamphlets etc, of which the most valuable for me is
your Cyperaceae. I have had no proper means before
this to study this interesting and difficult order.
I am glad that you also have sanctioned the use
of the minute and often microscopic characters; I find
them often of much more use than those commonly used
so with the Euphorbiae stipulatae, which I have studied
lately; they are beautifully distinguishedby their seeds!
What is E. maculata L? Some take it as a variety
of E. hypericifolia, others name your E. depressa (=E. thymifolia
of many authors) so; but Linnaeus calls it an assu[?]ent
plant. E. hypericifolia is the only one known to me with
black seeds in that section. All those with serrated leaves
        