PREFACE. 



This volume has been prepared expressly as a convenient 

 pocket manual for young Botanists as well as for those 

 more advanced in the science. It contains a copious G-lossary 

 of Botanical Terms, Analytical Tables and the Natural Orders, 

 illustrated by a Flora of Pennsylvania, in which are described 

 all, or nearly all, the indigenous and naturalized flowering 

 and filicoid plants of our State, together with some of the 

 more commonly cultivated exotics of the gardens; arranged 

 according to the Natural System now so generally adopted 

 in botanical works. But, in order to secure all the advanta- 

 ges of the Linncean System, and to render analysis as simple 

 as possible to the beginner, I have given a synopsis of the 

 genera, arranged under the respective classes and orders of 

 that system, describing the more prominent characteristics of 

 each, with a reference to the number of the page where the 

 genus and species are fully described in their respective 

 orders, in the body of the work. 



In preparing the glossary, analytical tables, and arrangiug 

 the natural orders my principal authorities have been " Gray a 

 Botanical Text Book," and a work by the same author enti- 

 tled " Botany of 'the Northern United States" — both American 

 works of the highest merit. With few exceptions I have 

 adopted the nomenclature of the "North American Flora' 1 

 of Torrey and Gray, for our native and naturalized plants 

 (so far as that flora now extends), and for our cultivated 

 exotics, the nomenclature of the " Prodromus" of De Can- 

 dolle, regarding these, as they truly are, standard works. 



In describing the genera and species together with their 

 locality, I have consulted Beck's "Botany of the United 



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