Wakeman—Pigments of Flowering Plants . 805 
molecule of water forming quantitatively the red phoeniceine 
C 14 H 14 0 6 . This reaction also takes place quantitatively upon 
long heating at 100° or heating for one hour at 150°-160°. 
Upon exposure to the air at ordinary temperature phoenin 
passes slowly to phoeniceine. 
Upon treatment with alkalies phoeniceine turns blue, then 
violet, and finally brown in color. Its behavior toward alkalies 
and acids is similar to that of the flavone compounds containing 
two hydroxy groups in ortho position. Kleerekoper 1 2 ) sug¬ 
gests the formula given above. 
Pigments referable to hydrocarbons of the formula of sat¬ 
uration Cn U 2n _ 12 
There exist in plants several pigments and pigment forming 
substances referable to hydrocarbons of this degree of saturation, 
all of which are substitution products of four different hydro¬ 
carbons, namely, naphthalene, two dihydro naphthalene deriva¬ 
tives with unsaturated side chains, and phenyl-diphenyl methane. 
Pigments referable to Naphthalene. 
CH 
CH 
CH 
COH 
iiCy 
N$/\v 
T i CH 
HC i \\ 
'xiCH 
hcL 
JL JcH 
c \^ 
hcL A 
X/ c 
JcH 
CH 
CH 
COH 
COH 
Naphthalene a Hydrojoglone 
Both of the hydro juglones exist, along with juglone, in all 
the green parts of the walnut tree, Juglans regia}) Upon oxi¬ 
dation a hydrojuglone yields juglone. A discussion of the var¬ 
ious quinhydrones and phenoquinones which may be formed by 
combination of the two hydrojuglones with juglone, also with 
possible higher oxidation products of juglone, has been given 
under juglone. 
1 Ber., 10, p. 1544; 17, p. 2411; 18, p. 204; 18, p. 474; 18, p. 2567. 
2 Jr. Chem. Soc., 69, p. 1355. 
