56 
Journal of Agricultural Research 
Vol. II, No. i 
areas of its cells, do we get the remarkably diversified blotching, streaking, 
speckling, marbling, or monochrome colorations which characterize the 
different varieties of cowpeas. 
A word should be said regarding the very interesting cases of distortion 
in the palisade cells mentioned under some of the foregoing varieties. 
Referring to the facts there mentioned, it will be seen that where the seed 
coat of the cowpea is white or cream white, as in Nos. 0362 or 17354, or 
where it has a certain white area, as in Holstein No. 239-4-3-6 or in No. 
239-5-3-18, or even in cases where there is merely a light speckling or 
dusting over of this cream-white color, as in Sport No. 5, in varieties of 
the Watson type, as No. 227-5-1 Re-17, i n certain individuals of No. 
17354, and in No. 0618, the palisade cells show great distortion of out¬ 
line and unevenness in the cell cavity. Furthermore, in most parti¬ 
colored cowpeas of strongly contrasted tints, such as Holstein No. 
239-4-3-6, or the black eye in No. 239-5-3-18, or the coffee-colored eye 
in No. 17354, the strongly colored areas have perfectly regular, symmet¬ 
rical palisade cells, while the lighter areas are more or less strongly con¬ 
torted in form and irregular in the cell cavity. In other words, there is 
traceable in all of these cowpeas a decided correlation between the mor¬ 
phology of the palisade cells and the suppression of the pigments in these 
cells. 
PLATE VI 
Fig. 1.—Transverse section of the seed coat of a cowpea, similar to that shown in 
text figure 1, but showing the relative thickness of three layers, as on the seed. The 
cells are not expanded with chloral hydrate, cu, Cuticle; a, palisade layer; b , middle 
or hour-glass layer; c, basal-color layer. Somewhat diagrammatic. 
Fig. 2.—Seeds of cowpeas, showing some of the variations in the style of marking of 
the seed coat. Natural size. 
