
          Barly Hort. Lit

-9 -

The catalog of the Bibliothèquee Nationale, moreover, is so accurate, and answers so
well all the requirements of critical bibliography, that its entries are as authoritative
as those of the L C printed cards.  Many of our titles are copied directly from it, and
these are authentic for copies in the  Bibliothèque Nationale. But as our checking was not
done until after many entries had been written up in present form, some of those marked
"Bib. Nat. Paris" may not correspond in all details with its own entries. So it will be
necessary to compare the entire list with the author catalog of the Bibliothèque Nationale,
confirming entries that have been accurately copied, correcting others, and probably adding
a good many works that have been heretofore overlooked.

It would be futile to check the entire list with the Union Catalog of Books in American
Libraries at the Library of Congress. This has proved to comprise few books within
the scope of the list, and none not previously located elsewhere, although it gives further
locations for some, chiefly of the "literary" sort, with which the list is already overloaded. 
Many of the libraries of this country that are strong in agriculture and horticulture
have been surveyed, and most of their rarer items have been cataloged by Miss Warner.
Titles that are credited solely to the New York Public Library, New York and Missouri
Botanical Gardens, and the private collections of "Greene" (now at University of Notre
Dame), and "Horton" (now at the John Crerar Library), are based on authentic cataloging,
and can safely be used as type entries. Although considerable cataloging was done thirty
years ago in several other libraries, notably those of the Arnold Arboretum and Massachusetts 
Horticultural Society, both of these have since published catalogs, from which many
titles have been added to the list. Since these catalogs do not conform in some ways with
the bibliographical requirements set as our ultimate aim, and as there is no way of distinguishing 
the original, authoritative entries from those copied from the catalogs, it
will be necessary to verify all the titles credited to those libraries.  It will doubtless
be practicable, however, to obtain verification of the majority of such details through
the courtesy of the libraries in which the books are locaated.

This collection of materials was begun with the idea that a really scholarly and definitive
bibliography might be possible through the cooperation of several libraries and
specialists, of course with competent general editorship. Most of the individuals who at
that time were leading authorities in certain branches of the subject have since died, and
some of the libraries have been damaged or destroyed. World War II wrought such havoc
        