PREFACE. 
Under direction of the Board of Trustees of the Missouri 
Botanical Garden, its third annual report is presented to 
the public. As best calculated to promote the objects of 
publication, the diffusion of information concerning the 
institution and of the results of scientific work done in 
connection with it, it has been decided that an annual 
volume shall be issued in the early part of the year, con- 
taining the official report of the President of the Board and 
the Director of the Garden for the preceding year, to- 
gether with such other matter as is considered pertinent. 
These volumes are primarily intended for distribution to 
botanical gardens, learned societies, and other scientific 
institutions, whose publications are desired in exchange; 
but when reason exists for it, they may also be sent to 
public libraries, or to individuals, although as a rule the 
latter cannot be carried on the regular mailing list for this 
purpose. 
The pages of each report are electrotyped, and in order 
that scientific papers may be issued promptly on their com- 
pletion, it has been decided that they may then be 
published, in advance of the volume, for which the electro- 
typed pages, bearing their original pagination at the bottom, 
will be held. In case of priority questions arising, there- 
fore, when separates have been issued in advance, reference 
must be made to these for actual date of publication. 
Separate copies of all scientific papers are printed, so that 
botanists not in| receipt of the complete reports may be 
supplied with those papers which are useful in their work. 
For the accommodation of persons who may wish the 
publications of the Garden, but feel that they are not 
entitled to receive them by way of exchange or as aids to 
(3) 
