68 COLORS OF VEGETATION. 
M. Cloez and others on the different varieties of hyacinth and 
bachelor’s button (Centaurea cyanus), that oxygenation or acid- 
ification changes vegetable blues to red, and that the two colors 
are chemically identical and chemically distinct from the yellow. 
In ordinary leaves, we find the blue and yellow substances nearly 
in equilibrium, but in the colored parts of the flower, one or the 
other predominates. Thus flowers are naturally divided by their 
colors into two great classes, according to whether the cyanic or 
xanthic principle is in the ascendant. 
Desvaux, one of the most painstaking of observers, has studied 
for ten years the gradations of color in the twelve hundred varieties 
which have been produced of the kidney bean. He divides the 
colors of flowers into two series. 
lst. The cyanic series, those having blue for their type and 
capable of varying to red or white, but never to yellow. 
2d. The xanthic series, those having yellow for their type and 
capable of varying to orange or white, never to blue. Both series 
commence in green, which is blue and yellow, and end in white 
which is the absence of all color. 
Thus the tulip was originally yellow. All of its varieties belong 
to the xanthic series. So with the dahlia and zinnia. There never 
was a blue tulip, primrose or dahlia. The geraniums, phloxes, 
verbenas, etc., vary throughout the cyanic series, and a Te 
geranium or phlox is unknown. 
Different species of the same genus sometimes basi to dif- 
ferent series, as is the case with the roses and violets. Rarely 
- different parts of the same flower belong to different series as in 
the convolvuli and forget-me-nots. Though the rules of color are 
- liable to many exceptions, yet it seems to me that Linnzeus’ great 
maxim ‘* Nimium ne crede colori,” ‘* Put not your trust in colors,” 
is too absolute. For example, the hue of a single petal of Solana- 
cez stamps at once the order. 
“The science of Vegetable Chromatology,” ohecevas M. Gué- 
rin, “is yet in its infancy; and it is impossible to establish any 
_ rules to which there are not many exceptions.” 
Ee All theories yet advanced, however ingenious they may be, are 
liable to objections of such great weight that none can be admitted 
as absolutely true. For example, let us take the theory of Mac- 
oe quart, that ‘‘ color results from the decomposition of carbonic acid 
and the — of oxygen, and that its intensity is propor- — 
