204 ANTHOCYANINS AND GENETICS 



planted in any aspect, and will come true even if sown in such different 

 climates as those of York and Pretoria. The crimson variety similarly 

 treated in York and in Pretoria gave the same flowers of a bronze old- 

 gold colour in both places, and the seed of this latter variety brought 

 from Pretoria and sown in York gave the same curious colour, in spite 

 of the great difference of altitude between the two localities. Cuttings 

 of the mauve variety could be grown in any aspect at Pretoria, without 

 any change in the mauve colour of the flowers. In addition to the 

 mauve and bronze old-gold colours, varieties of rose-salmon and of 

 sallow flesh-colour have been obtained, and no difficulty has been 

 experienced in changing any of the known orange, yellow, or scarlet 

 flowers into these curious colours." In a later paper, Rawson (600) 

 states that still further varieties have been obtained in England by 

 adopting the same methods. Pending confirmation it is difficult to 

 make anything of the significance of these facts. 



CONNECTION BETWEEN COLOUR AND OTHER PLANT CHARACTERS. 



There is little doubt that albinism, the most common form of 

 variation, brings with it in many cases a general weakness of constitution. 

 The true albino (see p. 158) of Antirrhinum majus, for instance, is more 

 stunted in growth than the coloured forms; it is also less resistant to 

 cold, drought and other adverse conditions. In connection with this 

 point there is a paragraph which may be quoted from the Flora Anomoia 

 (1817) by Hopkirk (428). This author evidently believed that lack of 

 robustness may cause variation for he says: "That these varieties of 

 colour are produced very frequently by weakness, is evident from the 

 circumstance of the variety being often much more tender than the 

 original species. The white-flowered variety of the Virginian Spider- 

 wort (Tradescantia virginica) is with difficulty preserved in the open 

 air during winter, whilst the blue is perfectly hardy ; in like manner, 

 the white Snapdragon 1 is much more tender than the common 

 Antirrhinum majus." We now know that the white variety of 

 Antirrhinum is lacking in the flavone, apigenin, as well as in anthocyanin ; 

 both these substances are of the aromatic group, and no doubt play 

 a certain part in general metabolism. It is also possible that other, 

 more fundamental compounds, such as oxybenzoic acids, the progenitors 

 of the flavones, are in addition absent from the white variety, and so 

 its metabolism, as regards aromatic substances, may in a sense be 



1 This may be the ivory and not the true white. It is of course impossible to know. 



