302 Miss M. Wheldale and Mr. H. LI. Bassett. 



have been described. In a more recent paper by both authors,* an account 

 lias been given of the identification of the ivory pigment of Antirrhinum with 

 apigenin, a flavone of known constitution, isolated by Perkinf from apiin, a 

 glucoside occurring in the parsley, Apium petroselinum. Apigenin is a very 

 pale yellow crystalline substance, readily soluble in hot alcohol, slightly so 

 in ether and almost insoluble in water. Melting point, 347° C. In the 

 Antirrhinum plant, apigenin undoubtedly exists as a glucoside, in which state 

 it is more soluble than after hydrolysis. 



Attention has been given subsequently to the yellow pigment and the 

 results are included in the present paper. The crude pigment prepared from 

 yellow flowers was extracted with ether by methods described in previous 

 papers. The ether extract contains apigenin from the tube and inner tissues 

 of the corolla, and yellow pigment from the epidermis of the lips, including 

 the patch on the palate. It was at first thought that the yellow pigments in 

 the epidermis of the lips and in the patch on the palate might be identical. 

 After removing the bulk of the apigenin from the ether extract by crystallisa- 

 tion from alcohol, the remaining yellow pigment, which is very soluble in 

 alcohol, gave, on fractional crystallisation from dilute alcohol, products of 

 which the melting points varied from about 250° to 338° C. 



The wide range of the melting points, combined with certain qualitative 

 reactions of these extracts, led to the conclusion that the palate contained 

 the lip pigment mixed with other pigments, or even other pigments without 

 the Hp pigment. Since, however, the patch on the palate is common to all 

 varieties (except white), the factorial difference between ivory and yellow is 

 only concerned with the yellow lip pigment. Hence, in order to simplify the 

 problem, the pigments of the palate have been disregarded for the time 

 being, and investigations have been limited to crude material (unfortunately 

 prepared only in small quantity) from the upper lips of the yellow 

 variety. In this product, it seemed more likely that there would only be 

 two pigments present to any extent. 



Even the more simple mixture presented very great difficulties in the 

 separation of yellow from ivory, both pigments having almost the same 

 solubilities in all solvents used. Such separation as was possible by means 

 of different solubilities gave products which indicated by their melting- 

 points, 300-328° C, the presence of luteolin, this substance being the only 



* Wheldale, M., and Bassett, H. LI., "The Flower Pigments of Antirrhinum majus. 

 II. — The Pale Yellow or Ivory Pigment," 'Biochem. Journ.,' 1913, vol. 7, p. 441. 



t Perkin, A. G., "Apiin and Apigenin," ' Chem. Soc. Journ., Trans.,' 1897, vol. 71, 

 p. 805 ; 1900, vol. 77, p. 416. 



