﻿1916] CURRENT LITERATURE 551 



cells; (4) mixtures with yellow pigments. The following are a few illustrations 

 of the significance of these factors: (1) The dark purple-red flowers of Centaurea 



Pelargonium bore mainly cyanin with a slight amount of pelargonin. This is 

 said to be the first plant in which a mixture of anthocyanins was found in the 

 same flower. (2) The bright red and dark red garden rose both bear cyanin 

 with a great difference in concentration. The flower of the field Centaurea 



purple double garden variety bears 13-14 per cent. (3) Blue flowers of 

 Centaurea contain potassium salts of cyanin, violet flowers of Delphinium 

 neutral delphinin, and scarlet flowers of Pelargonium tartrate of the antho- 

 cyanin. (4) The following yellow pigments may act with anthocyanins in 

 determining the flower color: (a) neutral carotinoids, carotin and xanthophyll; 

 (b) the glucosidic flavone pigments; (c) the little-known anthochlors of the cell 

 sap. It is found that the green color shown by a crude extract of antho- 

 cyanin of alkaline reaction results from the mixture of the blue of the alkali 



solutions, but intensely yellow in alkaline solution. This is suggestive to 

 breeders dealing with yellow and white flowers. 



We are coming to know something of the substances from which the antho- 

 cyanins originate, and the reactions by which they are produced. There are 

 many facts to suggest a close relationship between the yellow pigments of 

 plants of the favone or flavonol type and the anthocyanins. Combes 1 * has 

 made probable that this is a genetic relationship in obtaining anthocyanin by 

 the reduction of yellow pigments extracted from plants; and Everest's brings 

 still more evidence for the view that the anthocyanins originate from the 

 flavonol yellow pigments by a simple process of reduction. He has produced 

 anthocyanins by reducing flavonol glucosides and similarly anthocyanidins 

 by reducing the sugar-free flavonol derivatives. The following formulae 

 express his idea of the relation between the yellow flavonols and the chlorides 



'<Corr.pt. Rend. Acad. Sci. Paris 158:272-274. H>»4J Ber. Deutsch Bot. Gesells. 

 31:570-578. 1914. 



15 Jour. Genetics 4:361-367. 1915. 



