31 



The readsorption of the carotenoids, eluted from the s\igar, in 

 columns of magnesia facilitated the removal of traces of the green 

 pigments that are strongly and irreversibly sorbed« It also made 

 possible the separation of some xanthophylls such as lutein and 

 zeaxanthin and the carotenes c^-carotene and 3~c*^ro'tene that are not 

 separated in columns of sugar. 



The carotenoid pigments readsorbed in the magnesia columns were 

 recovered by elution vdth petroleum ether containing ethanol. These 

 eluted pigments were then transferred to petroleum ether and to etha- 

 nol for determination of the spectral absorption curves and to ethyl 

 ether for determination of the color reaction with concentrated hy- 

 drochloric aoido They were compared with authentic preparations of 

 various xanthophylls by adsorption of the mixtures in columns of pow- 

 dered sugar and in columns of magnesia-'-' « 



PIGMENTS OF HIGHER PLANTS AND GREEN ALGAE 



Chlo roplast Pigments of Flo-wering Plants ( Sperm atophytes) 



The pigments of flowering plants -were readily separable in a 

 column of powdered sugar and yielded a series of zones like those 

 shown in Figure II, lo The pigments were always a mixture of chloro- 

 phylls (chlorophylls a plus b) , xanthophylls (neoxanthin, "viola- 

 xanthin, and lutein plus zeaxanthin), and carotenes ((3-carotene plus 

 or minus oC-carotene) o The species that have been examined, their 

 habitats, the locations of the specimens and notes on the pigments 

 are presented in Appendix lo 



Occasionally traces of other pigments were observed in addition 

 to those indicated by Figure II, lo The cycads (Cycadaceae) , for 



