101 



ration. Strictly speaking, it is very seldom that two individuals exist which 

 are exactly the same. So, a species is generally represented by an individual. 

 That species which is generally used in systematic botany is, therefore, not 

 a species in my sense, but a group of several individuals that bear a close 

 resemblance. For convenience' sake, the term species is in the present paper 

 treated as a group like a genus or a family, only smaller than either of the two. 



4. WHAT THE RESEMBLANCE OF SPECIES DENOTES. 



Above, we have spoken of resemblance. But what is resemblance 

 manifested in an individual or in a species? According to my opinion, the 

 resemblance of individuals or species is not confined to cases of Wood-relation- 

 ship, but is manifested by the constitutional relationship. Now, what is meant 

 by constitutional relationship ? 



In my former paper, I proposed the participation theory to explain the 

 mutual relations of vegetable organs, individuals, or species. As the under- 

 standing of the mutual relations is in this case a most important matter, I 

 trust I may be pardoned if I repeat the theory in the following pages. 



% 5. THE PARTICIPATION THEORY 1 >. 



The theory is in fact but one theory, yet for convenience' sake I shall 

 treat it as two, namely : The theory of the mutual participation of the 

 gene 2) , and the theory of the mutual sharing of the gene. Literally speaking, 

 the word " participation " seems to express a united action of genes to produce 

 a certain result. Different genes participate in the effort to produce the 

 resulting plant or plant organ. Different plants or plant organs on the other 

 hand are found to share in the work of certain genes, or combination of genes ; 

 or perhaps we may say that the word " participation ' points to the future, 

 wliile the word " sharing " points to the work accomplished in the past. Thus, 

 different genes participate in the work of producing a certain result, wliile 

 different plants share with one another the work of certain genes. It must be 



1) In forrmilating this theory, I have been influenced by a suggestion from TENDAI'S theory 

 of mutual participation. 



2) As to what is the gene, readers are requested to refer to two similes given on pp. 103 

 anil 104 of the present paper. 



