8 



allowed; acknowledgments of assistance in this part of the work 

 arc due Capt. John Donnell Smith, of Baltimore, Md., and Dr. B. 

 L. Robinson, of Cambridge, Mass. This process of verification 

 has taken a great deal of time and has disclosed a very remarkable 

 number of inaccuracies in ordinarily accepted citations. The at- 

 tempt has so far succeeded that somewhat more than 98 per cent, 

 of the citations given are known to be exact, and a careful list 

 of the unverified citations has been kept for future reference. 



It will doubtless be found that in a very few instances the 

 committee has not carried out the instructions under which it was 

 acting, but in a work of such magnitude an occasional error could 

 hardly be prevented. Inasmuch as in the further exploration of the 

 area additional species and varieties are certain to be brought to 

 light, and the inevitable change in view from time to time relative 

 to the rank of various forms as species or varieties and of the limi- 

 tations of genera, will from time to time make other editions of 

 the list a necessity, opportunity will be afforded for the correction 

 of any errors which may have crept into the present work. 



As to the publication of the list, it was at first thought that the 

 committee might issue it as a pamphlet and assume the necessary 

 financial responsibility, but, this method being found impracticable, 

 a proposition from the editor of the Torrey Botanical Club to 

 publish it in the Memoirs of that organization was accepted. It 

 has been issued in signatures- to members of the committee and 

 such other botanists as have expressed a desire for it, each signa- 

 ture being dated with the day of delivery to the editor and dis- 

 tributed immediately thereafter. 



There has been brought together in an appendix to the list 

 the names of additional species and varieties found in the area 

 during the past season, which have been brought to the attention 

 of the committee, together with others inadvertently omitted in 

 the compilation and some corrections of citation. The committee 

 deems it desirable that appendices be published annually, so that 

 the record of plants occurring within the area may be kept up to 

 date, and that modifications of unverified citations may be indi- 

 cated when necessary. 



