20) ELEMENTS 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 tegmen 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 as well as the outermost part of the flower (the 
calyx). 
Cut sections of the soaked kernels, some transverse, some lengthwise 
and parallel to the flat surfaces, some lengthwise and at right angles to 
the flat surfaces. 
Make a sketch of one section of each of the three kinds, and label the 
dirty white portion, of cheesy consistency, embryo; and the yellow 
portions, and those which are white and floury, endosperm. ‘ 
Chip off the endosperm from one kernel so as to remove the embryo 
free 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.? 
Sprout a considerable number of kernels of corn in sand or pine saw- 
dust, at a temperature of 70 or 80 degrees, and make several sketches to 
illustrate the growth of the plumule and the formation of roots ; first 
a main root from the base of the caulicle, then others more slender 
from the same region, and later on still others from points higher up on the 
stem. The student may be able to make out what becomes of the large 
outer part of the embryo. This is really the single cotyledon of the corn. 
It does not rise above ground, but most of it remains in the buried grain, 
and acts as a digesting and absorbing organ through which the endosperm 
is transferred into the growing plant, as fast as it can be made liquid for 
that purpose. 
1The embryo may be removed with great ease from kernels of rather mature 
green corn after twenty minutes’ boiling on the cob, then picking the kernels off 
one by one with the point of a knife. They may be preserved indefinitely in 
alcohol, 
2The teacher may well consult Figs. 66, 67, 68 in Gray’s Lessons in Botany, 
revised ed. 
Ri 
