THE AMERICAN BOTANIST. 
47 
The red and blue coloring found in the leaves, flowers 
and fruits of many plants is due to a soluble pigment 
called anthocyan. It does not occur in grains like the: 
green and yellow pigments, but is dissolved in the cell sap.. 
When its condition is acid the color of the flower is red^ 
but when it is alkaline the color of the flower is blue. In 
the rose family there are no blue flowers because the cell 
sap is strongly acid. For the same reason there is but a 
single blue flowered species known among the orchids. 
On the other hand when the condition of the cell sap is 
nearly neutral the flower may readily change from one 
color to the other, or both colors ma^^ occur on the same 
flower-cluster, or even in the same flower, as has been 
observed in the hyacinths. Red coloration is much more 
common in foliage than blue, because the sap is usually, 
acid. It is believed to aid the plant in the w^ork of assim-; 
ilation by converting light rays into heat. Blue leaves, 
are rarer, but the upper foliage leaves of Protea globosa. 
of Australia, surrounding the bright yellow flowers, offer 
a good example of blue leaves, while the lower leaves are 
dark green. Anthocyan is probably a compound of a 
tannic acid and a sugar for it occurs only in plants con- 
taining tannic acid, and it rapidly increases when such 
plants are fed with an invert sugar. 
Readers desiring to pursue the subject further are 
referred to my papers in The American Naturalist, VoU 
XXXIII, page 493; Vol. xxxv, page 197; Vol. xxxvi, page 
203; Vol. xxxvii, page 365. 
Wnldoboro, Me. \ 
HAT flower shall be first to appear in spring seems 
W to be determined largely b3^ locality and exposure. 
A species which blossoms earliest in one locality may not 
be first in another. In rich woodlands the hepaticas 
(Hepatica triloba andH. acutiloba) seem to be among the 
earliest blossoms and I believe they are usually the first 
THE EARLIEST SPRING BLOSSOMS. 
BY WALTER ALBION SQUIRES. 
