44 



The Colours and Pigments of Flowers with Special Reference to 



Genetics. 

 By M. Wheldale. 



(Communicated by W. Bateson, F.B.S. Beceived October 31, 1908, — Bead 



January 28, 1909.) 



Investigations, of which the following is some account, have been 

 undertaken with a view to being of assistance in the interpretation of the 

 phenomena observed in the inheritance of flower-colour. An attempt has 

 been made to classify, of necessity roughly, the pigments, more especially 

 those soluble in water, found in flowering plants, and at the same time to 

 ascertain whether there is any connection between the genetic behaviour of 

 pigments and their chemical reactions and constitution. On the basis of 

 this classification it was thought that, at some future time, further investiga- 

 tions might be carried out in greater detail among the various classes of 

 pigments. 



This account deals more with yellow pigments than with red ; attention 

 was first directed to the yellow group, because of a certain correlation 

 between reds and yellows observed in the inheritance of flower-colour in 

 Antirrhinum majus, the relationship suggesting that a greater knowledge of 

 yellows might be useful in classifying the reds. No detailed examination 

 has been made of any one pigment, but merely a general survey of the 

 •colouring matters of genera from various natural orders. 



A classification in outline of the pigments, other than chlorophyll, found 

 in flowering plants has been given by many authorities * but perhaps 

 ■a repetition will not be out of place here, as follows: — 



A. Pigments in solution in the cell-sap.f 



(1) Soluble red-purple-blue pigments known as " anthocyanin " ; that this 



term includes several different classes of pigments seems probable 

 when observations are made as regards their behaviour towards 

 various reagents. The sub-classes will be described later. 



(2) Soluble yellow pigments known as "xanthe'in." Again, various sub- 



classes, to be described later, may be made according to their 

 reactions towards reagents. 



* General classifications and properties of pigments, as far as they are known, are 

 given by Czapek (4) and Zimmermann (13). 



t Said to be occasionally precipitated or crystallised out on natural concentration of the 

 cell-sap. 



