Trees of New York Shile 15 



sitler it but a variety ut" tlie P^uropeaii t'onii and iisi it as lictula 

 alba, var. papyrifera (Marsh.) Spach. 



The selection of the scientific names of plants depends upon 

 a complex system of rules based mainly on considerations of pri- 

 ority. Conservative botanists in this country are following a 

 universal, code of nomenclature according to a set of rules 

 promulgated at the International Botanical Congress, held at 

 Vienna, June, 1905.* The Vienna Code considers the first 

 edition of Linnaeus' Species Plantarum of 1753 as the logical 

 starting point for the nomenclature of the higher plants and 

 adopts the generic names used by Linnaeus in his text. These 

 were in part coined by Linnaeus himself and in part adopted 

 by him and his followers from pre-Linnean authors. In the 

 adoption of post-Linnean generic names, priority rules. The 

 Vienna Code likewise adopts the earliest specific name used to 

 designate a plant rather than that specific name which was first 

 combined with the correct generic name. Sassafras variifolmm 

 (Salisb.) Ktze. indicates that Salisbury first applied the specific 

 name of variifolium to Sassafras but used it with a difi'erent 

 generic name. Kuntze was the first to use the specific name of 

 variifolium correctly with the generic name, Sassafras. 



CLASSIFICATION OF PLANTS 



The ultimate aim of botanists and zoologists in the classifi- 

 cation of plants and animals has been to devise a "natural 

 system" of classification which would best indicate the natural 

 affinities of related forms. Such a treatment is both logical and 

 practical in that related forms are thus brought dow'U together 

 in congeries which permit of their identification and study 

 with greater ease. Experience has taught that in the higher 

 plants variation in the flower off'ers the best basis for a "na- 

 tural" classification. Plants exhibiting likeness or parallelism 

 in floral structure are found to share other characteristics in 

 common which indicate clearly their common lineage. It is cus- 

 tomary to consider those plants first which are conceded to 

 have the simplest or most primitive flowers, thence to proceed to 

 forms with greater specialization, considering those last which 

 have the most complex flowei-s. The system is open to criticism 

 in that it is sometimes difficult to determine whether a flower 

 is inherently primitive in structure or simple by reduction. 



In classification plants are first divided into large divisions 



There is also a Rochester and an Ameriran Code. 



