1912.] Tlie Oxydases of Cytisus Adami. 465 



produce only self- (uniformly) coloured flowers in the following year. More- 

 over growers associate the phenomenon of breaking of wallflowers with some 

 abnormality in the development of the " wood." Again, in the case of stocks 

 it is correlated with a blotched form of leaf : the plants which bear flaked 

 flowers possess leaves with irregular light green patches. It may be that 

 certain tissues of the vascular system are to be regarded as secretors of 

 oxydases which have among other functions the formation of flower pigments 

 and that, with the oxydase-secreting mechanism out of gear, the uniformity 

 of colour of the flowers is destroyed. 



To this subject, however, we hope to return. 



In conclusion we wish to express our thanks to Mr. W. Watson, Curator 

 of the Eoyal Gardens, Kew, and to others for supplying us with material for 

 this investigation and have to acknowledge the assistance which we have 

 derived from a grant by the British Association. 



EEFEEENCES. 



1888. Darwin, Charles, 'Animals and Plants under Domestication,' 2nd edit., pp. 413 — 

 417. 



1909. Baur, " Pf ropf bastarde, Periclinalchimaren und Hyperchimaren," ' Ber. Deutsch. 



Bot. Ges.,' 1909, vol. 27. 



1910. Buder, J., " Studien an Laburnum Adami," ' Ber. Deutsch. Bot. Ges.,' 1910, 



vol. 28. 



1912. Keeble, F., and Armstrong, E. F., " The Distribution of Oxydases in Plants and 

 their Role in the Formation of Pigments," ' Eoy. Soc. Proc.,' 1912, B, vol. 85, 

 p. 214. 



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