Bulletin - United States National Museum - Smithsonian Institution

PREFACK.
The outline of this work was presented as a communication to the
Philosophical Society of Washington, January 22, 1881. The aim of
the writer was to furnish a guide to botanists in exploring the locality
and an aid to beginners in practical botany. To this latter class the
Appendix is especially addressed, but as it is equally applicable toother
localities, and as nothing, it is believed, analogous to it has been pub-
lished, it may be found useful outside of Washington. The introduction
also contains suggestions which, if followed in a sufficient number of
localities by those pieparing local catalogues, would greatly aid in
making the botanists of the country acquainted with the geographical
distribution of plants thoughout the United States and the special peculi-
arities of certain regions.
Tlie manifest imperfections of the treatise may not be without their
uses in stimulating local collectors and others to correct them and pro-
duce something better.
In the investigation of the flora of Washington, so many able and
active botanists and so many energetic amateurs have co-operated that
it would almost seem invidious to single out any as the subjects of
special thanks, and it has been deemed the most equitable plan to give
^special credit to the first discoverer of each rare jjlant, wherever this can
be known, under its proper head in the detailed enumeration. I cannot,
however, refrain from expressing my special obligations to Dr. George
Yasey, Botanist to the Department of Agriculture, for his kindness in
placing the National Herbarium at my disposal and in examining and
reporting upon many critical and puzzling forms, especially in the
OyperacesB and Graminese. I also desire to acknowledge in an especial
manner the valuable services of Mr. M. S. Bebb, of Eockford, 111., in
identifying the local Salices, which, though comparatively few, are very
interesting and in a high degree confusing to any but a trained specialist
like Mr. Bebb.
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