14 ESSENTIALS OF BOTANY 
Sketch an unsoaked kernel so as to show the grooved side where 
the germ lies. Observe how this groove has become partially filled 
up in the soaked kernels. 
Remove the thin, tough skin from one of the latter and notice its 
transparency. This skin —the bran of unsifted corn meal— does 
not exactly correspond to the testa and inner coat of ordinary seeds, 
since the kernel of corn, like all other 
grains (and like the seed of the four- 
o'clock), represents not merely the seed, 
but also the seed-vessel in which it was 
formed and grew, and is therefore a 
fruit. 
Cut sections of the soaked kernels, 
some transverse, some lengthwise and 
parallel to the flat surfaces, some length- 
wise and at right angles to the flat sur- 
faces. Try the effect of staining some 
of these sections with iodine solution. 
Fic. 6. Lengthwise Section Make a sketch of one section of each 
of Grain of Corn. (Magni- of the three kinds, and label the dirty 
Hiéd about three mrs) white portion of cheesy consistency, 
y, yellow, oily part of endo- embryo; and the yellow portions and 
sperm; w, white, starchy part : : : 
‘af enaospernis ws plomules those which are white and floury, endo- 
s, the shield (cotyledon), in Sperm. 
contact with the endosperm Chip off the endosperm from one 
for absorption of food from kernel so as to remove the embryo free 
a i from other parts.! Notice its form, 
somewhat triangular in outline, sometimes nearly the shape of a 
beechnut, in other specimens nearly like an almond. 
Estimate what proportion of the entire bulk of the soaked kernel 
is embryo. 
Split the embryo lengthwise so as to show the slender, somewhat 
conical plumule.? 
1 The embryo may be removed with great ease from kernels of rather 
mature green corn. Boil the corn for about twenty minutes on the cob, then 
pick the kernels off one by one with the point of a knife. They may be 
preserved indefinitely in alcohol of 50% or 75%. 
2 The teacher may well consult Figs. 56-61, inclusive, in Gray's Structural 
Botany. 
