be made b.y means of the decimal system. For example, if a new species 

 is to be added after No. 1866, it will be numbered 1866.1. Additions 

 will only be made on the basis of good herbarium specimens. It is 

 much better to have a small, reliable list than a large one with many 

 doubtful entries. The introduced species have been designated by 

 some phrase by which they can be distinguished from the indigenous 

 species. 



The nomenclatuie used is tliat of Britton and Brown's "An Illus- 

 trated Flora of the Northern United States, Canada, and the British 

 Possessions," second edition. The few names which differ because of 

 a different conception of the genus will cause no special trouble in 

 reference. "Kellerman's Fourth State Catalogue of Ohio Plants" 

 was based on the first edition of the "Illustrated Flora," and thus the 

 names following the "American Code" on the principle of priority 

 have been used very generally in Ohio since that time. The author 

 sees no reason for abandoning the principle of priority at the present 

 stage of progress of botanical knowledge. 



The arrangement of the species and larger groups follows strictly 

 the phyletic classification. The time has come when taxonomy must 

 readjust itself to the more modern conceptions in regard to morphology 

 and evolution. 



The map of Ohio by counties will enable one to see, at a glance, 

 the distribution indicated, and whether a given species is considered 

 rare or unusual in any locality. It will now be possible to concentrate 

 attention on the exact distribution of our more interesting plants 

 and in the near future data should be at hand to definitely delimit the 

 natural plant regions of the state. When this can be done, a consider- 

 able advance will have been made in the knowledge of the natural agri- 

 cultural and horticultural regions of Ohio. 



A number of useful lists have been published in the past which 

 are still available. Among these may be mentioned the following: 



Poisonous and Other Injurious Plants of Ohio. Ohio Nat. 4 : 16-19 ; 

 32-35; 69-73. 1903-1904. By the author. 



Medicinal Plants of Ohio. Ohio Nat. 10 : 55-60 ; 73-85. 1910. By 

 Freda Detmers. 



The Non-Indigenous Flora of Ohio. Univ. Bull. Series 4, No. 27. 

 1900. By W. A. Kellerman and Mrs. Kellerman. 



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