No. 494] 



PARASITIC PLANTS 



reproduction were, at most, only slightly disturbed. So 

 distinctly are the systematic characters of normal pheno- 

 gams retained in the florescence and fruitage of the para- 

 sites that one seems forced to the conclusion that, in the 

 great systematic development of vegetal forms, they all 

 became phenogams before they became parasites. The 

 phenogamous parasites, therefore, not only do not belong 

 to a separate and predatory class, as is the case with 

 other parasites, but they are depraved members of the 

 same class, and sometimes of the same family, with their 

 hosts. Still, their depravity is only with reference to 

 the habits and structure of normal plants, for they all 

 have great adaptability to their peculiar conditions, and 

 their vegetal vigor is quite as great as is that of normal 

 plants. 



It is a fact worthy of special attention in this connec- 

 tion that although all the various forms of phenogamous 

 parasitism are accompanied by greater or less abnormal- 

 ity of structure, they are in certain respects subject to the 

 systematic restrictions which pertain to normal plants. 

 That is, each form of parasitism affects not merely cer- 

 tain individual members of a given species, but every 

 member of it; and the systematic limits of that species 

 are, for itself, the limits of its own peculiar form of para- 

 sitism. Moreover, that form of parasitism which char- 

 acterizes each of the different groups is shared without 

 variation by every member of the group regardless of 

 the generic or family relationship which it may bear to 

 other plants. The habits and other parasitic characters 

 of those depraved phenogams are as distinctly and per- 

 manently heritable as are the stated specific, and other 

 systematic, characters of the same, or of any other, 

 species, and there is no known evidence that any form of 

 phenogamous parasitism has been derived by transmu- 

 tation from any other parasitic form. Known evidence 

 tends to show that every case of such parasitism origi- 

 nated independently of all other cases, and by a mutative 

 process which imposed permanent abnormal characters 



