INTRODUCTION. XXXV 



That teratology may serve the purposes of syste- 

 matic botany to a greater extent than might at first 

 be supposed becomes obvious from a consideration 

 of such facts as are mentioned under the head of 

 Peloria, while the presence of rudimentary organs, or 

 the occasional appearance of additional parts, or other 

 changes, may, and often do, afford a clue to the relation- 

 ship existing between plants a relationship that might 

 otherwise be unsuspected. So, too, some of the altera- 

 tions met with appear susceptible of no other expla- 

 nations than that they are reversions to some pre- 

 existing form, or, at any rate, that they are manifes- 

 tations of a phase of the plant affected different from 

 that which is habitual, and due, as it were, to a sort of 

 allotropism. 



The mutations and perversions of form, associated 

 as they commonly are with corresponding changes of 

 fimction, show the connection between teratology and 

 physiology a connection which is seen to be the 

 more intimate when viewed in the light afforded by 

 the writings and experiments of Gaertner, Sprengel, 

 and St. Hilaire, and, in our own times, especially by 

 the writings and experiments of Mr. Darwin, whose 

 works on the ' Origin of Species,' and particularly on 

 the ' Variation of Animals and Plants under Domesti- 

 cation' comprise so large a collection of facts for the 



in the way above mentioned are made use of in the following pages. 

 The inconsistency manifested by their use may be excused on the 

 ground of ignorance of the true structure, and by the circumstance that 

 in many cases facts alone are recorded without an explanation of them 

 being oflfered. Moreover, it is desirable to act in conformity with the 

 usual practice of botanical writers, and not to change established 

 terminology, even if suspected to convey false ideas, until the true 

 condition of aflfairs be thoroughly well ascertained by organogenetic 

 research or other means. 



