Apr. is, 1914 
Coloration of Seed Coat of Cowpeas 
45 
tortion or other modification of form. This hybrid is the second genera¬ 
tion of a cross of Watson No. 5 on Coffee No. 27. 
No. 228-5-4 is usually black, but shows great variability in its color 
scheme, ranging from uniform black into black with small irregula* 
fawn-colored or reddish brown marbling, or a fawn and reddish brown 
marbled with black, or having blue-black speckles, or in rare instances 
the entire cowpea is a uniform fawn or light red brown, especially imma¬ 
ture seeds. There are, therefore, three pigment elements to be consid¬ 
ered: (1) Deep blue or black areas, (2) blue-black speckled areas, and 
(3) fawn to red-brown basal areas. 
The deep-black areas show that this color is an intensification of a 
strong purple in the pigment cells, which, although it is present in all the 
cells of such areas, is still quite variable as to quantity, some cells being 
pigmented only in the extreme lower end and others through the entire 
cell cavity. On treatment with neutral water this color resolves into 
the two factors before noticed—namely, a rose-colored anthocyanin very 
uniformly distributed throughout this layer and an indigo-blue antho¬ 
cyanin massed in the lower end of certain cells. It is therefore evident 
that these black areas would show a somewhat mottled condition if the 
excessive pigmentation did not obscure this. 1 
The second pigment element—namely, the blue-black speckling—shows 
a very different condition of things. This also is due to an anthocyanin 
deposit in the palisade cells, but it is clearly distinguishable from what 
was found in the solid black areas in four respects: (1) The color is always 
a vivid indigo blue, not a purplish blue, nor does it give a rosy diffusion 
in water; (2) the quantity of this blue pigment is very much greater in 
the cells producing the speckling than in those found in the solid black 
areas; (3) it always extends upward toward the top of these cells, instead 
of being segregated into a heavy mass at their base; (4) the cells con¬ 
taining this particular pigment are in small groups, not solid masses as in 
the black areas, but usually large enough to be seen by the unaided eye. 
This is the Taylor or New Era type of speckling. 
The third and remaining color is that of the fawn or reddish brown basal 
tint, which is due to the usual melanin-like compound contained in the 
cells of the basal-color layer. It ranges from a faint yellow to an intense 
yellow or even a copper color. This variation in quantity is the cause of 
the difference in color of individuals, ranging from pale fawn to reddish 
brown. 
The palisade cells are strikingly regular, straight in outline, narrow in 
diameter, and long. The entire seed coat is somewhat heavier than usual. 
The grandparents are Clay No. 17 crossed on Coffee No. 27. 
1 Prof. W. J. Spillman has informed the writer that among cultivated cowpeas these black areas occur 
only in hybrids having all the factors for black pigment and having also the factor for the Taylor or the 
New Era style of speckling, and also that such a type can not be fixed in cultivated cowpeas, although 
it is the normal condition in wild cowpeas. 
36123 14—4 
