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in flowering plants, flowerless plants and green algae indicates a 

 close relationship among these organismSo The siphonalean green algae 

 ■with siphonaxanthin, siphonein and much o(-carotene in addition to the 

 pigments of other green algae appear as a distinct modification of the 

 green algae. The Euglenas with chlorophylls a and b and ^-carotene 

 but with unique xanthophylls are a distinct group remotely related to 

 the other algae. With respect to pigments, the Chrysophta are a di=" 

 verse groupj the Bacillariophyceae or diatoms with chlorophylls a and 

 Cj fucoxanthin, diatoxanthin, diadinoxanthin and ^-carotene are dis- 

 tinct from the Heterokontae with chlorophyll a, unique xanthophylls 

 and fl= carotene. Actually, the diatoms and the brown algae (Phaeophyta) , 

 with the same chlorophylls, a and c, the same principal xanthophyll, 

 fucoxanthin, and the same ^-carotene, are much more alike than the di- 

 atoms and the Heterokontae, The dinof lagellates with chlorophyll c 

 but with a unique principal xanthophyll, peridinin, must represent a 

 distinct group remotely allied to diatoms and brown algae. Red alga©, 

 many with the minor chlorophyll d and all with the water-soluble, red 

 r=phycoerythrin, form another distinct class as do the blue=green 

 algae with myxoxanthophyll, myxoxanthin and the blue c=phycocyanino 



The chromatographic adsorption methods have revealed that, in 

 solution, the plant pigments undergo various isomerization and alter- 

 ation reactions yielding a variety of colored products. Great care 

 must be exercised in the extraction and isolation of the pigments to 

 prevent contamination of the natural pigments with these alteration 

 products. 



By contrast with their lability in solution and in injured or 

 anesthetized plant tissues, the chloroplast pigments are remarkably 



