Jamea. ^^Q [February, 



Although he commenced the Enumeration in 1813, it was not fully 

 elaborated for the press until the winter of 1824-25. Its issue was 

 retarded, in the meantime, on account of the appearance of Pursh's 

 valuable Flora, and subsequent publication of Nuttall's excellent 

 work on the North American Genera, but more especially of Dr. Bar- 

 ton's Flora Philadelphica, which latter comprised the greater portion 

 of the plants of his district ; all seeming to him to supersede the 

 utility of his project, and, for a time, he relinquished the idea of 

 printing the work. 



Believing, however, in the good results of local Floras in the deve- 

 lopment of science, he brought his labor to a close. 



In the ardor of the pursuit of his object, he had the satisfaction 

 of communicating a taste for botanical investigations to a number of 

 the intelligent gentlemen of his vicinity, who, in return, afforded him 

 assistance in his work. 



The Enumeration was published under the title of " Florula Ces- 

 trica." The motto adopted for the work, a line from Horace, is charac- 

 teristic of the author, — " Ore trahit quodcunque potest atque addit 

 acervo." 



In 1837 he published the Flora Cestrica, a more extended work, 

 being an attempt to enumerate and describe the flowering and filicoid 

 plants of Chester County, Pennsylvania, adopting the Linnsean ar- 

 rangement, whilst the modern botanical world had so generally aban- 

 doned it for the natural method. He considered the latter as yet not 

 sufficiently established in its details for his purposes, although freely 

 admitting that the true science of vegetables could only be attained 

 by a philosophical investigation of their structure, functions, and 

 natural affinities; yet he could not help thinking that even the super, 

 ficial knowledge of genera and species so readily acquired by the 

 Linngean system, of advantage to the learner, by exciting an early 

 interest and facilitating his first steps. Of this edition, it must be 

 admitted, that a more comprehensive description of each species of 

 a genus has rarely been given to the public in this country. 



A third edition of the Flora Cestrica appeared in 1853, arranged 

 throughout according to the natural system, to which was added those 

 plants which had been found to exist in the County since the pre- 

 ceding one was published, and it was extended so as to embrace the 

 Anophytes and the Thallophytes. The author contemplated, when 

 this revised edition was commenced, to have inserted a brief descrip- 

 tion of all the indigenous species of the Vegetable Kingdom which 

 had been detected in the County, together with such introduced 



