870 Wisconsin Academy of Sciences, Arts, and Letters. 
Malvinidin was found by Willstaetter to exist in the violet 
flowers of the wild mallow, or wood mallow, Malva sylvestris, 
where it occurs in combination with two molecules of glucose 
as the diglucoside malvin. Malvinidin is isomeric with oenidin, 
also with rhamnazin, a dimethyl ether of quercetin. 
II. PIGMENTS REFERABLE TO DIHYDRO ANTHRACENE AND HOMO- 
LOGUES. 
A. Pigments referable to dihydroanthracene. 
B. Pigments referable to homologues of dihydroanthracene. 
1. Pigments referable to methyl -1- dihydroanthracene. 
2. Pigments referable to methyl -2- dihydroanthracene. 
Most if not all of the plant pigments referable to dihydro- 
anthacene and its homologues, are derivatives of anthraquinone 
and its homologues, the quinones being tetrahydroxy derivatives 
of the underlying hydrocarbons. 
O 
1 Ann., 408, p. 122. 
