Variations in the proportions of the leaf pigments were observed in 

 Syngonium (Araoeae) which contained much neoxanthin and little Tiola- 

 xanthin, in Solidago (Compositae) which contained much violaxanthin, and 

 in Fremontia (Sterculariaceae) Tdiich contained an amount of zeaxanthin 

 equal to or greater than the luteino 



There was no simple relation between the pigments of leaves and the 

 pigments of flowers and fruits „ l/ttien flowers were immature and green 

 they usually contained the same pigments found in leaves and in other 

 green tissues as green fruits and bark„ But when they matured, the 

 flowers usually lost the chloroplast pigments. Many flowers then de- 

 veloped red and blue water-soluble pigments. Some flowers, particularly 

 the yellow ones, developed carotenoid pigments that were present in the 

 green tissue, as violaxanthin in pansy flowers. But some flowers de- 

 veloped unique carotenoid pigments that could not be detected in the 

 green tissues. Examples of these \uiique flower pigments are taraxanthin 

 of the dandelion, Taraxacxam (Compositae) , and echscholtzxanthin of the 

 California poppy, Eschscholtzia (Papaveraceae)^., In the green fruits 

 of the tomato, the chloroplast pigments are superseded during ripening 

 by the polyene hydrocarbon lycopene which does not occur in the leaves. 



Su pplemental Pigments of Leaves 



Leaves of a few plants develop supplemental pigments when the growth 

 is retarded as at the onset of winter-^s^« In many leaves there is ex- 

 tensive loss of the chloroplast pigments sometimes accompanied by the 

 formation of fat-soluble, carotenoid pigments-*^* ■'■'-'« An unusual carote- 

 noid called rhodoxanthin has long been known as a constituent of the 



T 11 



winter foliage of certain conifers »» 



