30 NATURE STUDY AND AGRICULTURE 
the germ. Of course, in some seeds the embryo is better developed and 
more easily found than in others. 
In case of the bean, the two halves are the seed-leaves or cotyledons. 
Between them, near one end, lies the plumule, which is the bud of that 
portion of the plant that will rise above the cotyledons. The little peg 
near the plumule, just outside the cotyledons, and attached to them 
and to the plumule, is the caulicle or radicle, the rudimentary stem which 
supports the cotyledons and pushes them out of the ground as it elon- 
gates, and from the lower end of which the roots spring. 
4. This experiment will establish the very important fact that air 
is necessary for germination. Seeds planted too deep, or in ground that 
is packed too hard, or in ground that is water-soaked cannot sprout, 
because air cannot get to them. 
5. When farmers or gardeners are in doubt about the viability of 
their seeds they test them before planting them and thus avoid disap- 
pointment afterward. This experiment gives a good way to conduct the 
test. Record the results in this form: 
SAMPLE TOTAL STRONG MEpIuM WEAK DraD 
No. 1 100 
6. Inthe bean the caulicle lengthens, and as one end is firmly anchored 
by means of the roots, the other end pushes or drags the large cotyledons 
with it to the surface, where the caulicle soon straightens up, the cotyle- 
dons part, and the plumule unfolds its leaves. The cotyledons may turn 
green and leaf-like, but in the course of a week or so they shrivel and die, 
the food stored in them having been absorbed by the growing plant. 
7. Squash, pumpkin, cucumber, and melon come up in the same 
manner as the bean: the caulicle elongates and pushes the rest of the 
seed out of the ground. Notice that often the seed coats are not shed 
until the cotyledons expand after they reach the surface. In the case 
of these species the cotyledons grow, become green, and perform the 
