224 APPENDIX 



Delphinidin C 15 H 10 7 . 

 Delphinin == diglucoside of delphinidin + 2 mols. of ^-oxybenzoic acid. 



Flowers of purple var. of Delphinium Delphinin 



,, blue type of ,, Potassium salt of delphinin 



Fruits (purple) of Vitis vinifera Oenin monoglucoside of 



oenidin which is the 3 : 4- 

 dimethyl ether of delphi- 

 nidin 



Flowers of reddish-purple Malm sylvcstris ... Marvin = diglucoside of malvi- 



din which is a dimethyl 

 ether of delphinidin and is 

 isomeric with oenidin 



Fruits (purple) of V actinium Myrt'dlus ... Myrtillin=glucoside( ? sugar) of 



myrtillidin which is the 

 7-monomethyl ether of del- 

 phinidin 



Flowers (? purple) of Althaea rosea Althaeiin=monoglucoside( ?dex- 



trose) of myrtillidin 



From the data given above certain conclusions can be drawn. First, 

 that the purple anthocyanidins, delphinidin and cyanidin, contain more 

 oxygen than the redder pelargonidin, and this is in accordance with 

 the hypothesis originally suggested by the author (212, 217). Moreover, 

 when a purple type gives rise to a red variety, the variety may contain 

 a less oxidised anthocyanin, and not necessarily the acid salt of the 

 pigment of the purple type, as in Centaurea and Dahlia, of which the 

 purple variety contains cyanin, and the red pelargonin. This is again 

 in agreement with the author's original views. Secondly, the evidence 

 at present seems to point to the fact that variation may also be due to 

 the effect of other substances in the cell-sap, as for instance in Delphinium 

 and Centaurea, of which the blue type contains the alkaline salt of the 

 pigment of the purple variety. Willstatter is of the opinion that varia- 

 tion in flower-colour largely depends on the presence of these other 

 substances, acids, alkalies, salts, etc., in the cell-sap. For instance, 

 he says, the scarlet Pelargonium contains an acid salt of pelargonin, 

 but in the flowers of the bluish-pink P. peltatum and in the pink Cen- 

 taurea the pelargonin is probably in either an acid-free or basic form. 

 This view is supported by the fact that artificial basic salts of pelargonin 

 can be formed: 



(C 2 7H 3 i0 15 Cl) 2 + C 27 H 30 15 . 



In the flowers also of the variety, 'Alt-Heidelberg', of the Dahlia 

 the florets vary from scarlet to violet, and yet pelargonin only is present. 



A third point to be considered is that a flower may contain two 

 anthocyanins simultaneously as in the violet-red variety of Pelargonium 



