ETIOLOGY OF MALFORMATIONS 189 



tral flowers, such terminal flowers are almost without exception peloria ; 

 but lateral flowers may also develop as peloria. The influence of position 

 upon the dorsiventral or radial construction is here unmistakable, although 

 the attempt to prove this by experiment has been scarcely successful. 

 Thus Hoffmann 1 endeavoured to arrive at the formation of peloria by 

 placing in a vertical position the flower-buds of Achimenes grandiflora, 

 Salvia Horminum, Gloxinia speciosa, and other plants ; but the negative 

 outcome of such an experiment is of course evident from the first, because 

 at the time when one can operate upon flower-buds which are laid down 

 dorsiventrally their construction has already reached such a stage that no 

 essential change is to be expected. Numerous as are Hoffmann's experi- 

 mental cultures they can scarcely be cited as of critical value. Peyritsch 

 has endeavoured to discover the immediate cause of the formation of peloria 

 in another way, as he states in his paper cited above. Starting from 

 observations made upon plants in their natural habitats he asked himself 

 whether the formation of peloria could not be caused by a change in the 

 conditions of life, and experiments with Galeobdolon luteum and Lamium 

 maculatum proved that this is the case. It is true that the experiments 

 leave many important questions still unanswered, nevertheless I mention 

 their results because an extended repetition of them is most desirable. 



The plants of Galeobdolon luteum grew in their natural habitat 

 under the shade of other plants. If now the shading was removed, for 

 instance by cutting down the trees in the vicinity, peloria frequently 

 appeared, and along with them other anomalous conditions of the flowers. 

 The conclusion was then natural that the increase of the intensity of 

 light (or transpiration) was the cause of the malformations of the flowers, 

 and the experiment obviously supported the correctness of the view 

 that a change of the conditions of life induced variations in plants. The 

 plants were then placed in localities with stronger insolation, but un- 

 fortunately no control experiment was made such as the division of 

 the stock and the placing of a portion of the plants in normal shady 

 places. Some of the plants developed no flowers at all ; others changed 

 their time of flowering and the flowers appeared upon shoots which 

 normally possessed no flowers ; three individuals produced terminal peloria ; 

 two remained normal in the main, but in one of them there appeared 

 a flower abnormal in the numerical relation of the flower-leaves. In the 

 following year the abnormal phenomena were less marked, the plants 

 appeared to be getting accustomed to the new conditions of life, and that 

 the formation of flowers was generally lessened may be explained by 

 the unfavourable influence exerted upon the whole growth. In Lamium 

 maculatum similar anomalies appeared, but, as in Galeobdolon, they never 



1 Hoffmann, in Kotan. Zeitung, 1875, p. 625. 



