44 
Journal of Agricultural Research 
Vol. II. No. i 
action of this powerful liquid for some time. This layer in water shows 
as a deep orange-buff color, due to the melanin-like pigment generally 
found in this layer. 
The scheme of coloration is produced by the blue-black pigment above 
mentioned superimposed upon the strong-clay or light-coffee color found 
in the basal-color layer. The strong pigmentation around the hilum is 
identical in character with that found on the rest of the seed coat. This 
hybrid is the second generation of a cross between a blue Taylor No. 20 
and a Red-Eye No. 26. 
A very similar cowpea in general color scheme is the so-called blue 
Macassar No. 21299a. The seed coat ranges in various individual cow- 
peas from an almost purple blue to a complete black. Transverse 
sections of the seed coat show that the pigment, a blue black, is somewhat 
unevenly distributed throughout the palisade cells, although no cells 
seem to be absolutely destitute of it. Associated with this blue black is 
a small quantity of rose-colored pigment which occupies the upper part 
of the cell, the deep blue being uniformly found in the lower one-third. 
This rose-red pigment, an acid anthocyanin, is quite evenly distributed 
through the palisade layer, so that the inequality in the pigmentation of 
the seed coat, which may be detected with a hand lens, is due to the 
unequally deposited deep-blue, alkaline anthocyanin. 
A mere suggestion of a faint buff pigment was detected in the palisade 
cells, presumably the melanin-like material found in this position in 
other cowpeas. But as the quantity, if present, is too small to play any 
r 61 e in the coloration and its presence in any quantity is unverified, it 
may be left out of consideration. It should also be stated that in this cow- 
pea a test for tannin shows that an unusual quantity of some one of this 
group of compounds is present in the palisade cells. 
The basal-color layer is strongly pigmented with the usual deep yellow 
melanin-like substance. The intense color superimposed upon this by the 
contents of the palisade layer probably prevents its having any consid¬ 
erable effect in the exterior coloration of the seed coat. 
This variety was secured from Piracicaba, Brazil, May, 1907. There 
are no data on its parentage. It may be stated that in Brazil all varieties 
are called “macassar.” 
In No. 227-2-4, a black cowpea, all of the cells of the palisade layer 
are well filled, at least in the upper two-thirds, with a rose-red acid antho¬ 
cyanin. Somewhat less than one-half contain also an extremely dense 
and granular indigo-blue alkaline anthocyanin. In cells destitute of the 
latter the rose anthocyanin fills the entire cell. Were it not for the 
intense coloration due to the rose anthocyanin the unequal distribution 
of the indigo-blue pigment would result in a blotched or speckled condi¬ 
tion of the seed coat. The basal-color layer is a pale-straw tint or some¬ 
times merely a cream white. The palisade cells are free from all con- 
