Gray, who ardently desired th.at these valuable materials should
be used in continuation of the plan begun by the donor, it was
arranged that I should undertake the work in connection with
Mr. Thomas P. James, of Cambridge, who would make the
microscopical analyses of such species as had not yet been
satisfactorily examined, and prepare sketches from which
descriptions could be drawn.
As large numbers of specimens and even whole collections
were sent to us for determination, the work progressed slowly,
but it was drawing toward completion when two years ago Mr.
James was suddenly called away by death.
I have since finished the descriptive part of the work, with
assistance from Mr. T. Renauld, an eminent French bryologist,
in the examination of some Htjpneoe that had not been surely
determined.
But I was prevented by age and. sickness from visiting Cambridge
in order to complete at the library of the Herbarium
the bibliographical part of the work, which could not be done
with the few books at my disposal. In the emergency, having
greatly admired the manner in which Mr. Sereno Watson —
not a professed bryologist — had elaborated the Mosses of the
Botany of California, I besought his assistance, little comprehending
at the time the weight which I was imposing upon one
whose time and energies were already overtasked. This labor
of révisai, and the charge of the work in its progress through the
press, Mr. Watson at length consented to undertake, especially
through rog.ard to the memory of his friend, my associate, Mr.
James. It has involved a large amount of critical .and editorial
labor, and I deeply regret th.at I am permitted to do no more
than to acknowledge, as I gr.atefully do, my profound obligations
to him. But I may bespeak the thanks of all those who
are to use this volume, which he has made much more valuable
and better adapted to their needs than it vrould otherwise have
been.
This Manual of American Mosses is believed to include
descriptions of all the species of mosses (about nine hundred)
that are as yet known to occur on the North American Continent
within the limits of the United States and northward.
It includes the results of the researches of Sullivant and myself,
continued until 1872, as well as those of James, Austin, and
Rau, and also such species as have been described by European
bryologists, Schimper, Mitten, Mueller, Hampe, Lindberg, etc.
L e o L e s q u e e e t j x .
C o lum b u s , O h io , M a y , 1884.