Apr. is, 1914 
Coloration of Seed Coat of Cowpeas 
5i 
and pale representation of the pigment usually present. The pale-cream 
color of this cowpea is doubtless due to the small quantity of melanin-like 
pigment diffused through the basal-color layer, and the streaked and 
indistinct marking of the seed coat is caused by the minute quantity of 
the same pigment unevenly distributed in the palisade layer. It is 
interesting to note that the palisade cells in the neighborhood of the hilum, 
where the color is quite intense and forms what is known as the “eye,” 
are very much larger than on the rest of the seed coat and almost entirely 
free from the contortion and twisting already mentioned. In other 
words, the irregularity of form seems to be directly connected with the 
white or cream-white character of the seed coat. This same remarkable 
parallel has already been noted in several other cowpeas. The basal- 
color layer in the neighborhood of the hilum is very heavily charged with 
a melanin-like pigment, but there is here a somewhat unusual arrangement 
in that the lower cells of this layer are of a somewhat pale lemon yellow, 
while the separated masses in the upper part of the layer are a deep orange 
or orange buff. The reactions of these two, however, are identical. No 
information has been obtained as to the parentage of this variety. 
IV.-COWPEAS HAVING BOTH A MELANIN-TIKE PIGMENT AND ANTHOCY- 
ANIN IN THE PALISADE LAYER 
The fourth class includes all cowpeas showing both anthocyanin and 
melanin-like pigment in thepa lisade layer. The first one to be mentioned, 
No. 214-5-10, is generally described as having buff markings upon a black 
ground. The fact is that it is a cowpea with a strong buff basal color 
almost covered with large black areas. In other words, the black is super¬ 
imposed upon the buff and not the buff upon the black. The two 
colorations of the seed coat are accompanied by a quite different condition 
of the palisade layer. A melanin-like substance is to be found in all 
pigment cells of the seed coat both in the buff and in the black areas. 
An acid anthocyanin is present in all the palisade cells of the black areas, 
but in no case in those of the buff areas. An alkaline anthocyanin is to 
be found in one-half to three-fourths of the palisade cells of the black 
areas, but in none of the cells of the buff areas. In all cases the alkaline 
anthocyanin is massed in the lower end of the cell cavity and the acid 
anthocyanin occupies principally, if not wholly, the upper half of the cell 
cavity. The color produced by these two anthocyanin pigments is a 
more intense purple than has been found in any other cowpea, and when 
the rose colored acid anthocyanin is extracted, the indigo-blue or alkaline 
anthocyanin found in one-half to three-fourths of the cells of the black 
areas is larger in quantity and more vivid in color than is generally the 
case. In the buff areas there is evidently neither of these phases of 
anthocyanin. These cells are, however, pigmented with the melanm-like 
material found in other cowpeas. A comparison of the form of the 
palisade cells in the two areas is also of interest. Those in the black 
