16 ORDERS AND GENERA. 



or sub-generic, — as to the special character which sepa- 

 rates closely allied orders, — and as to whether certain 

 genera are rightly placed in this or in that order. Mere 

 trifling on the sense of words ! The correct answer is, 

 that the groups are ordinal or sectional, generic or sub- 

 generic, — this or that character to be taken as the test of 

 each, — and consequently certain genera to be placed in 

 this or in the other order, — only as the systematists may 

 agree among themselves that they shall be so called, cha- 

 racterised, or assigned ; — not because any such special 

 groupings, and tests, and assignments exist in nature. 



More reasoning men regard ordinal and generic names 

 simply as so many terms, useful and needful for ex- 

 pressing conventional groupings of plants, according to the 

 kind and closeness of their resemblances, or of some of 

 their resemblances. Doubtless the similarities are facts 

 in nature ; and the groups are admitted to be " natural " 

 in proportion as their included plants resemble among 

 themselves, and differ from the excluded plants. But 

 whether their similarities shall be grouped into one hun- 

 dred or into three hundred named orders, — into five 

 thousand or into ten thousand named genera, — or into 

 some intermediate numbers, seems to be almost purely 

 optional and arbitrary with systematists. And further, 

 whether the similitude shall be sought in the flowers, 

 fruits, stems, leaves, stipules, or other parts, is also in 

 great measure arbitrary or optional. The fancy or deci- 

 sion of each single systematist, however, is so much 

 checked and controlled by the fancies or decisions of 

 rival systematists, that the general result becomes con- 

 ventional rather than individually optional. 



By way of explanatory illustration, it may be remarked, 

 that Jussieu was equally sound and correct in grouping 

 plants into one hundred orders, as is Dr. Lindley in 



