Miss Wheldale, On the nature of anthocyanin. 



147 



Rhamnetin, CifiHi207, a rnonomethyl ether of quercetin is found 

 as a rhamnose glucoside — ' xanthorhamnin' * — in fruits of Rhamnus 

 spp. Its constitution may be represented as : — 



CO 



OH 



OH 

 Isorhamnetin, CisHjgOy, an isomerous monomethyl ether, occurs in 

 the flowers of Gheiranthus cheiri and oi Delphinium Zalil: it may 

 be represented as : — 







OH 



OCH, 

 OH 



OH 



OH CO 



Rhamnazin, C17H14O7, a dimethyl ether of quercetin, occurs as a 

 glucoside in addition to xanthorhamnin in the fruits of Rhamnus 

 spp. ; it may be represented as : — 



O 



^CHj 



onr Y \ — <r %0H 



OH CO 

 Fisetin, CigHjoOe, occurs in the wood of Rhus cotinus, R. coriaria 

 and R. rhodanthema. 



It differs from quercetin in containing a resorcinol instead of 

 a phloroglucinol nucleus and may be regarded as a tetrahydroxy 

 flavone : — 



OHf/ Y V-<^ ^OH 



OH 



CO 



Hence on fusion with caustic alkali, the decomposition products 

 are protocatechuic acid and resorcinol, 



* Cp. " On some points in the Histology and Physiology of the Fruits and Seeds 

 oi Rhamnus." H. Marshall-Ward and J. Dunlop, Ann. Bot. Vol. i. 1887-8. 



