CAROTINOIDS IN THE PHANEROGAMS 59 



Nailiiiirki (Cypress), Ts\vHt. 

 ]''n/-i ]>li<ilurtox ]li.[(lt'hminllii A. Hr. and Bourhe, Lubimeuko. 

 Jnnipirus riri/iu/acn (Hod Cedar), Tswett. 

 M ncrozani'ut species, Lubiincnko. 

 Iiftinoxpora phtmoxa (Juvcnilo Thuja), Tswett. 

 Seloginella (Club Moss), Molisch, Lubiinenko. 

 Taxus baccata (Yew), Tswett. 

 Thuja oricntalis (Arbor Vita?), Tswett, Monteverde and Lubimenko. 



Opinion was divided even among the older investigators as to 

 whether one or several pigments arc involved in the autumn colora- 

 tion, and as to what relation they bear to the normal pigments of the 

 green leaf. Among those who believed that only one pigment is 

 involved may be mentioned Pringsheim (1874), whose spectroscopic 

 observations of extracts of yellow autumn oleander leaves and rye 

 straw showed three absorption bands in the blue only. Pringsheim 

 concluded that the pigment involved was different from his etiolin, 

 and he adopted Berzelius' name of xanthophyll for the yellow autumn 

 pigment. Tschirch (1884) also believed that only one pigment exists 

 in yellow autumn leaves, which he called ft xanthophyll, to distinguish 

 it from an a xanthophyll, the yellow pigment in green leaves, although 

 he regarded the two xanthophylls as closely related, if not identical. 

 Tschirch believed that there was less xanthophyll in autumn leaves 

 than in green leaves. The pigment thus described by Tschirch was 

 probably carotin. Immendorff (1889) succeeded in obtaining carotin 

 crystals from alcoholic extracts of the yellow autumn leaves of the 

 beech (Fag us) and elm (Ulmus campestris) , and although he admits 

 that he secured a very small quantity and that only in one case, his 

 extracts always showed the carotin spectrum, which caused him to 

 conclude that carotin is the cause of the yellow autumn coloration. 

 Tammes (1900) examined the fallen autumn leaves of a number of 

 trees and shrubs after submitting them to the Molisch alkali crystal- 

 lization method. The plants examined are given in Tables 1 and 2. 

 Carotinoid crystals were observed in all cases in which the leaves still 

 showed the presence of yellow plastids. Tammes' conclusion that car- 

 otin is the cause of the yellow autumn coloration is, of course, not 

 valid, in view of the fact that we now know that the Molisch reaction 

 is not specific for carotin. 



In view of the multiplicity of carotinoids at present acknowledged 

 to exist in the chloroplastids the idea of only one pigment in the yellow 

 autumn coloration is not acceptable. A number of the older investi- 

 gators concluded that more than one pigment was involved even 



