^ 



J 1 1 



l_, 



Sugar maple 

 {Acer saccharum) 



GENUS AND SPECIES 



Red maple 

 {Acer rubrum ) 



Striped maple 

 {Acer pennsylvanicum) ■. 



After you know a maple from an elm or an oak, you may continue to give the name 

 "maple" to trees that are in many ways distinct. When you get to know sugar-maples, 

 for example, from red-maples, and after you find them to remain consistently like 

 other sugar-maples and consistently different from red-maples, you attach to the 

 general or genus name qualifying or species labels. From the time of Linnaeus 

 scientists have systematically used double names — a general name and a special 

 name — for every species. For example, we use the Latin "genus" name Acer to 

 denote maple, and the Latin "species" names saccharum, rubrum, and pennsylvani- 

 cum to designate particular kinds of maple 



When we say that all mankind make up one species/ Homo sapiens, we 

 mean that all human beings alive today had the same ancestors thousands 

 of gefieratiofis bacl{. When we say that all the greenish frogs are of the 

 species Rana virescens, we mean that they are all descended from a common 

 ancestor. Of course we cannot "prove" this through family records, for 

 either frogs or men. But we have good reasons for assuming that there is 

 this connection between members of a species. At any rate, the usual idea 

 of a "species" is "all the individuals are enough alike to let us assume that 

 they descended from a single pair." 



How Are Different Species Related? Linnaeus recognized that only 

 by using double names could we have distinct names for each species. 

 ^The word species has the same form in the singular and plural. 



37 



