256 SOME RECENT RESEARCHES IN PLANT PHYSIOLOGY 



they established a close parallel between depth of colora- 

 tion and intensity of oxidase action. Very similar results 

 were obtained with Dianthus barbatus and Geranium 

 sanguineum, for the details of which the original papers 

 should be consulted. They also proved that the white 

 patches in coloured flowers and the unmasked appearance 

 of the yellow eye of the flower were due to inhibitor, for 

 addition of oxidase reagents failed to result in the colora- 

 tion of such regions till after treatment with hydrogen 

 cyanide, whereby the inhibitor was removed. 



THE OXIDASES OF CYTISUS ADAMI. 



By application of a-naphthol and benzidine as micro- 

 chemical tests for oxidases, Keeble and Armstrong (1912, 2) 

 obtained striking confirmation of the correctness of Baur's 

 (1909) brilliant researches on the constitution of Cytisus 

 Adami. These have recently been summarized both by the 

 above authors and by Skene (1914), so a very brief account 

 will here suffice. 



Baur regards C. Adami as a periclinal chimsera, an or- 

 ganism the outer parts of which are composed of one species, 

 and the inner of another. As is well known, this inter- 

 esting plant was obtained many years ago by the French 

 gardener Adam, supposedly by grafting C. purpureus on 

 C. laburnum. To this chimaera C. purpureus has given 

 only the single-layered epidermis, whilst the other tissues 

 are formed from C. laburnum ; for while C. purpureus has 

 purple flowers, and those of C. laburnum are yellow, 

 C. Adami bears yellow and purple flowers, and in addition 

 buff ones. The latter arise from the combination of a 

 purple epidermis with hypodermal cells containing yellow 

 plastids. Keeble and Armstrong have summarized their 

 results in the accompanying scheme, which needs no ex- 



