6 FOUNDATIONS OF BOTANY 
Observe particularly how the sand is pushed aside by the rise of 
the young seedlings. 
‘Fic. 1.—Lengthwise Section 
of a Squash Seed. (Magni- 
fied about five times.) 
Suggest some reason for the manner in which 
the sand is penetrated by the rising stem. 
' 2. Examination of the Squash Seed. — 
Make a sketch of the dry seed, natural size. 
Note the little scar at the pointed end of the 
seed where the latter was attached to its 
place of growth in the squash. Label this 
hilum. ; 
Note the little hole in the hilum; it is 
the micropyle, seen most plainly in a soaked 
seed. (If there are two depressions on the 
hilum the deeper one is the micropyle.) 
Describe the color and texture of the outer 
coating of the seed. With a scalpel or a very 
sharp knife cut across near the middle a seed 
that has been soaked in water for twenty- 
four hours. Squeeze one of the portions, 
* held edgewise between the thumb and finger, 
in such a way as to separate slightly the 
halves into which the contents of the seed is 
naturally divided. Examine with the mag- 
nifying glass the section thus treated, make ~ 
a sketch of it, and label the shell or covering 
of the seed and the kernel within this. 
Taking another soaked seed, chip away 
the white outer shell, called the testa, and 
observe the thin, greenish inner skin (Fig. — 
1, e), with which the kernel of the seed is — 
closely covered. 
Strip this off and sketch the uncovered ker- 
nel or embryo. Note that at one end it tapers 
to a point. This pointed portion, known 
as the hypocotyl, will develop after the seed — 
sprouts into the stem of the plantlet, like that shown at ¢ in Fig. 2. © 
Split the halves of the kernel entirely apart from each other, 
- 1 See footnote 2 to Sect. 18. 
