Wakemaffr— Pigments of Flowering Plants. 
879 
Hystazarin exists in the Chay root, Oldenlandia umbellata, 1 
in the form of its monomethyl ether. 
Hystazarin crystallizes in orange yellow needles which mell 
at 260°. It is difficultly soluble in hot alcohol,* ether, acetone, 
and acetic acid; insoluble in benzene and toluene; soluble in 
solutions of alkalies with a blue color, of ammonia with violet, 
and of acids with a red color. It forms a dark violet cal¬ 
cium 2 salt and a dark blue barium salt. It is not satisfactory 
as a dye. 3 
Hystazarin monomethyl ether crystallizes in orange yellow 
needles which melt at 232°. It is soluble in alkalies with a red 
color. 
Xanthopurpurin or Purpuroxanthin. 
Xanthopurpurin the dihydroxy -1, 3- anthraquinone exists in 
the rhizome of Rubia tinctorium d 
Xanthopurpurin crystallizes in yellow needles and sublimes 
in yellowish red needles. It melts at 262°-263°. It is easily 
soluble in alcohol, benzene, and acetic acid. By heating with 
alkali in contact with air it is transformed into purpurin, tri¬ 
hydroxy -1, 2, 4- anthraquinone. Xanthopurpurin imparts 
a rather fugitive yellow color to fabrics mordanted with alum¬ 
inum. 
1 Rroc. Chem. Soc., 23, p. 228 ; Jr. Chem. Soc., 63, p. 1160. 
2 Ber., 28, p. 118. 
* Ber., 35, p. 1778; 21, p. 2501. 
* Bull. Soc.. Chim., 4, p. 12. 
3 Ann. de Chim. et de Fhys., (5) 18, p. 224. 
