TBJ} NAMING OF SPECIES 



429 



552. Kinds of plants which, in the judgment 

 of any author, are not distinct enough to be 

 called species, are called varieties; and the full 

 designation of the variety is rendered in three 

 words, — the generic, specific and varietal names. 



552a. Thus, the name of the black maple is commonly written 

 Acer sacoharinum, var. nigrum; but there are some botanists who 

 prefer to regard it as a species and to call it A.eer nigrum. This 



Fig. 432. 

 Spray of black maple. 



maple affords a good illustration of the different views which may 

 be held as to the name and classification of any plant. The 

 black maple is shown in Figs. 432 and 263; the sugar maple, in 

 Figs. 433 and 262. They are distinct enough; but in some re- 

 gions they are so much alike (they "run into each other") that 

 botanists prefer to regard them as one species. 



553. It often happens that two authors inad- 

 vertently give the same name to different plants. 

 It is, therefore, customary to cite the author of 

 the name, or an abbreviation of his name, with 



