56 



in each gender. The specific part of the name must agree in gender 

 with the generic part. The generic name Quercus is feminine, hence 

 the Red Oak is known as Quercus rubra while the generic name Acer 

 is neuter, hence the Red Maple is known as Acer rubrum. 



The scientific names used in this publication are those found in 

 the Seventh Edition of Gray's Manual of Botany, and are in keeping 

 with the rules of nomenclature laid down at a Congress in Vienna. On 

 account of the present unsettled condition of our nomenclature it is 

 often possible to find a certain species designated by two or more dif- 

 ferent scientific names, e. g., the Scrub or Bear Oak is known as 

 Quercus ilicifolia, Wang. ; Quercus nana, Sarg. ; or Quercus pumila, 

 Sudw. The authorized scientific name is given at the top of each 

 descriptive page, and where other scientific names are in common use, 

 they are given as synonyms just below the authorized one or in 

 the description. 



The mere knowledge of the names of trees is of little value or 

 satisfaction. The name is simply a means by which to come nearer 

 to the plant. Learning the names of trees serves about the same 

 purpose as learning the names of persons. It is merely an introduc- 

 tion which allows us, in fact often stimulates us, to become more 

 intimately acquainted with their life-processes, associations, en- 

 vironments, and commercial importance. 



Explanation of Terms and Headings : 



Some readers no doubt will find terms in this publication whose 

 meaning they do not know. Some of the terms have been discussed 

 at length in Part I while others will be defined in a glossary follow- 

 ing the description of the species. The description of the species of 

 trees contained in this publication is subdivided into a number of 

 headings. Most of these headings are discussed at length in Part I. 

 The significance and scope of those headings not discussed in Part 

 1 will follow at this point. Under the several headings is given such 

 descriptive material which will be of value not only to the student 

 of Dendrology but also to the layman who may know little concern- 

 ing the characters and habits of trees. The headings have been so 

 selected and treated that one should be able to identify our com- 

 mon trees at all seasons of the year. 



Under the heading "Distinguishing Characteristics" ajre given 

 both general and specific characteristics by which the species can be 

 recognized. The species are usually compared with other rather 

 closely related ones with which they might be confused. The dis-' 

 tinguishing characteristics and comparisons are based upon the trees 

 native to Pennsylvania, and consequently do not embrace other 

 closely related species found outside of the State. 



