4 FLORA OF PHILADELPHIA. 



paratively new to science, or it may be, that the plants are too 

 inconspicuous and the characters are not sufficiently well marked 

 to attract the attention of the ordinary observer. 



Upon the common name follows a reference to the page in 

 Britton's Manual upon which the species is described in detail. 



Next follow the data given by the different contributors and 

 in each case the authority is mentioned. The key to the ab- 

 breviations of names is found appended. 



A general statement in regard to habitat and time of flower- 

 ing is also made. 



When no data are added, the plant is considered to be of 

 general distribution. 



All data from New Oastle County have been furnished by Mr. 

 Edward Tatnall, except where otherwise mentioned. 



The information in regard to Bucks County has been revised 

 by Dr. C. D. Fretz, who has just completed a revised catalogue 

 of that region. 



The data from Delaware County were revised by Mr. Ben- 

 jamin H. Smith, who, for many years, has made a careful study 

 of that county. 



Thanks are due to Miss Lillian Roseman, who assisted ma- 

 terially in the arrangement of the information supplied. 



