PHENOLIC SUBSTANCES 215 



clear-cut rationale, and the data are evaluated conservatively. In this 

 work several species of Gaillardia were analyzed for anthocyanins. 

 Inter-specific differences involved particular cyanidin glycosides, and 

 the patterns conformed somewhat to the sub-generic disposition. Color 

 variations of geographic races of G. pulchella were found to involve 

 only quantitative differences in the three anthocyanins present. A 

 quite similar study of Papaver species was reported by Acheson et al. 

 (1956) with similar conclusions. Griffiths (1960), who compared the 

 seed polyphenols of various species of Theobroma and the related 

 genus, Herrania, could discover no general taxonomic implications 

 aside from the fact that he concluded that it is reasonable to suppose 

 that the genus Herrania is closely related to Theobroma. This con- 

 clusion, based solely on the chemical data, is questionable, however, 

 because again, only the common polyphenols were considered. 



The phytochemical systematic studies of Erdtman (1956, 1958) 

 are especially interesting. He found a distinctive combination of 

 phenolic substances in the heartwood of the genus Pinus where 

 the compounds accumulate as inert deposits. Erdtman believes 

 that secondary constituents are generally far more useful in sys- 

 tematic studies than the basic metabolites such as sugars, certain 

 common fatty acids and amino acids. This same position has been 

 taken by others as noted elsewhere. Erdtman favors the bark and 

 wood constituents. He states (1956): 



It is clear that compounds which occur in phylogenetically young, 

 highly specialized organs will possess a lesser taxonomic interest 

 especially when they take part in some of the biochemical processes 

 specific to the organ. 



If the statement given above is intended to refer to flower 

 parts, it is more applicable to phylogenetic problems involving the 

 higher taxonomic categories, perhaps not at all applicable to problems 

 of systematics of the lower categories. 



Phenolic compounds from the genus Pinus include the 

 following: 



(1) Stilbenes 



HQ 



CH ^ , 



HO 



pinosylvin 



pinosylvin monomethyl ether 

 pinosylvin dimethyl ether 



