254 INFLUENCE OF CORRELATION AND EXTERNAL STIMULI 



The facts recorded of Goldfussia l (Fig. 127) have led me to the 

 view that internal relationships of symmetry have also to do with the 

 anisophylly- the position of the lateral shoots to the chief shoot for 

 example; and this is an opinion at which Wiesner 2 has also arrived after 

 special study of the problem of the furtherance of the outer side of 

 the lateral shoots. I cannot however agree with Wiesner that it is the 

 strong influence of relative position to the mother-shoot upon the unequal 

 leaf-development that brings it about that ' If strong stems provided with 

 axillary shoot-primordia of Urtica dioica or Scrophularia officinalis come 

 to be horizontal there are developed on the sides of these stems axillary 

 shoots with strong anisophylly on which the outer leaves, that is those 

 turned away from the mother-axis, are more developed than the inner, 



FIG. 127. Goldfussia glomerata. Scheme of the phyllotaxy and leaf-symmetry. The leaves stand at first in 

 decussate pairs, but are subsequently displaced to the position represented. 



that is those turned towards the mother-axis ' ; there may have been here, 

 so long as the shoot was still vertical, an ' induction ' of the bud which only 

 found expression in the horizontal position. 



In conclusion I must say a word about an experiment of Frank 3 . 

 He inverted a horizontal twig of Acer platanoides when its terminal bud 

 was so far opened that two pairs of leaves were visible. The first pair 

 of leaves in spite of the altered position retained the primarily induced 

 differentiation 4 ; the second pair did so only at the beginning, later the 

 leaf now lying undermost surpassed the upper ; and in the third pair 

 this was the case from the beginning. Light however was here not 



1 See what I have said about Centradenia grandiflora in Botan. Zeitung, 1880, p. 840. 

 - Wiesner, Anisomorphie der Pflanze, in Sitzungsber. d. Wiener Akad. d. Wissensch. ci., Abt. i 

 (1892), p. 701. 



3 Frank, Uber die Einwirkung der Gravitation auf das Wachsthum einiger Pflanzenteile, in Botan. 

 Zeitung, 1868, p. 873. 



4 Weiss confirmed this by experimental growths on the klinostat, but added nothing new to what 

 I had already proved in the case of Aesculus. 



