TERATOLOGY IN MODERN BOTANY. 89 



and it implies that although in many cases the agent is an 

 external one, there is an internal factor also, that is to say, a 

 predisposition to the production of the anomaly. One may 

 convince one's self by experience that all individuals of a 

 given species do not react to an external influence of an 

 unfavourable character in the same way at all times, nor is 

 the capacity to vary or to appear under abnormal forms, to 

 suffer from disease, equally present in all in che same 

 fashion."^ And the experiments of De Vries, above re- 

 ferred to, lead to the same conclusion. 



For our present purpose it is indifferent whether peloric 

 flowers be regarded as malformations or as examples of 

 "reversion to type". Without doubt the radial forms of 

 inflorescence represent an earlier type of flower-disposition 

 than the dorsiventral (zygomorphic) flowers which are 

 normal to the plants referred to. 



As regards the etiology of peloria it is known that when 

 flowers are developed at the apices of stems the remainder 

 of the flowers upon which are zygomorphic, these apical 

 flowers are, almost without exception, radial (peloric), but 

 laterally situated flowers 7;my also develop as peloric ones. 

 The influence of position upon zygomorphy is thus here 

 unmistakable, though the attempt to prove this by strict 

 experimental methods is an exceedingly difficult task. Thus, 

 although Hoffman'-^ endeavoured to produce peloric flowers 

 in Achiinenes grandijiora, Salvia Horinimun, Gloxinia 

 speciosa, and others, the negative results of these experi- 

 ments would seem to have been a foregone conclu- 

 sion, made, as they were, by causing the flower-buds to 

 assume a vertical position artificially. By the time that 

 the flower-buds, zygomorphically arranged, are amenable to 

 treatment, their development has advanced to such a point 

 that it is useless to expect any modification of importance 

 to take place. Hence Hoffmann's experiments are scarcely 

 capable of being employed for critical purposes, numerous 

 though they were. 



Peyritsch, in his work already referred to, endeavoured 



1 Deiikschriften der K. k. Akad. JV/en, bd. ^8, 1S78. 

 - Botan. Zeitmig^ p. 625, 1875. 



