FLORAL COLOURS AND PIGMENTS. 



468 



FLORAL COLOURS AND PIGMENTS. 

 By John Bidgood, B.Sc, F.L.S., F.R.H.S. 



A knowledge of floral pigments and their colour effects should be very 

 useful to anyone who is concerned with plant hybridisation for flower 

 production, because without some knowledge of these subjects the 

 operator is to a great extent working in the dark. For it is material 

 substances which are inherited, and not qualities or properties unattached 

 to matter. A plant does not inherit colour or colours from its parents, 

 but the pigments which possess colour or colours as their most distinctive 

 properties ; and it does not necessarily follow that, inheriting the pigment, 

 it inherits the parental hue of that pigment. Or it may inherit from one 

 parent an uncoloured substance which, being present in the hybrid with a 

 pigment derived from the other parent, may modify the pigment so that 

 its colour is altered. Or it may even inherit from each parent an un- 

 coloured substance, which in the hybrid may react on each other and 

 produce a pigmented substance. 



Some knowledge of the subject is also most useful to the selector. 

 For although nature produces colour varieties by the suppression or even 

 occasionally the production of pigment, and the horticulturist can do 

 nothing but wait and take advantage of each variation as it appears, yet 

 such knowledge might prevent much time being wasted, and hopes being 

 vainly entertained of getting colour varieties which may be in the nature 

 of things impossible. 



The subject is a large and a difficult one, with physical, physiological, 

 chemical, and biological sides, and much work has been done and much 

 written about it. The chemistry of the pigments is especially difficult, 

 and commences with the great difficulty of isolating most of them from 

 other plant products, so that they may be obtained in a state of purity. 

 The physics and physiology of colour, colour effect, and colour perception 

 have been greatly advanced of late years, principally in connection with 

 photographic processes, but there are still many problems to be solved. 

 The biological side of the subject is chiefly concerned with questions of 

 the inheritance of pigment, and the losses and gains of pigment which 

 constitute colour variation, and here great confusion exists, for both 

 Mendelists and Anti-Mendel ists have concerned themselves very little 

 about the inheritance of pigment, and much about the inheritance of 

 colour, which is quite another matter. 



As this paper is chiefly a resume of what is known of floral pigments 

 and their colour effects, there is no need to discuss the question of the 

 uses of pigments to the plant. It is sufficient to say that " they have for 

 the most part solely a biological significance, being commonly used for 

 attractive purposes in floral organs, &c, and in leaves and young stems 

 serving as a protection against excessive insolation. In other cases the 

 colour is simply an accidental property of certain products of metabolism." * 

 * Pfeffer's Plant PhyfiioUxjy (English translation), vol. i. p. 405. 



