SMITHSONIAN INSTITUTION 
UNITED STATES NATIONAL MUSEUM 
No. 49. 
Within the last few years there has been among systematic botanists both 
in Europe and America a marked increase of interest in the Violaceae. 
The numerous collections of material gathered in remote parts of the country, 
experiments in cultivation carried on at widely separated stations, and above 
all the exhaustive and critical field study recently devoted to the genus have 
contributed to a clearer understanding of the characters on which species 
are to be based in this group. 
As a natural result of such activity numerous new species have been pro¬ 
posed, while others, established in the early part of the century by Leconte, 
Schweinitz, Pursh, and Nuttall have been revived from synonymy. It is 
believed that a distribution of authentic material of every North American 
species, through the United States National Museum, will be of the highest 
value to American systematists; this conclusion has been justified by the 
encouraging responses and the accumulation of specimens received in reply 
to requests therefor. Prof. Edward L. Greene, who has given the family most 
exhaustive field and bibliographical study, and is our foremost authority on 
the Violaceae, has kindly consented to aid Mr. Charles Louis Pollard, Assistant 
Curator in the Division of Plants, U. S. National Museum, in the work of 
identification and verification, thus greatly enhancing the importance of the 
distribution. 
The sets of specimens will be offered by the National Museum in return 
for an equivalent amount of selected duplicates, either in the Violaceae or 
other groups, so that the exchange will be mutually beneficial to the Museum 
and its correspondents; they will be issued in decades at irregular intervals 
as rapidly as material can be secured and labels printed. Forty sets will be 
prepared, but the number may be increased later if it is found advisable. 
While an effort will be made to have the sets as far as possible uniform, the 
Museum will reserve the right to substitute specimens of the same species 
from other localities in case the original supply becomes exhausted. For 
example, if Viola pedata L. figures as one of the species in a certain decade, 
the locality from which the specimens are obtained will be considered of 
secondary importance to the identification of the species, the object being 
to furnish authentic material of every species distributed. 
Franks for the transmission of specimens will be furnished on application. 
To facilitate prompt attention, these, as well as envelopes in which letters are 
sent, should be endorsed with the words “ North American Violaceae.” 
Address correspondence to 
FREDERICK W. TRUE, 
Exectttive Curator , U. S. National Museum. 
Washington, D. C., 
Oct. 16, 1899. 
