18 PRACTICAL COURSE IN BOTANY 
remove the hard coat, or testa, as it is called. The thin, green- 
ish covering that lines it on the inside is the endosperm. How 
does it compare in quantity with that in the corn and castor 
bean? How do the cotyledons compare in thickness with 
those of the bean? Carefully separate them and draw, label- 
ing the parts as you make them out. The tiny pointed 
object between the cotyledons at their point of union is the 
plumule ; is it as well developed as in the bean? Can you see 
any reason why seeds like the pea and bean, which have coty- 
ledons too thick and clumsy to do well the work of true leaves, 
should have a well-developed plumule, while those with thin 
cotyledons, like the squash and pumpkin, do not, as a general 
thing, form a large plumule in the embryo? The little pro- 
jection in which the cotyledons end is the hypocotyl; which 
way does it point? Where did you find the micropyle to be? 
Test the cotyledons and some of the endosperm for food sub- 
stances ; what do you find in them? 
15. Study of a pine seed. — Remove one of the scales from 
a pine cone and sketch the seed as it lies in place on the cone 
scale. Notice its point of attachment to 
the scale, and look near this point for a 
small opening, which you can easily recog- 
nize as the micropyle. The seed with its 
| wing looks very much like a fruit of the 
: V maple, but differs from it in being a naked 
ie 28. seed borne on the inner side of a cone scale, 
Fies. 27, 28. — ‘ 5 
Pitch pine seeds: Without a pod or husk or outer covering of 
27, seale, or open any kind, such as beans and nuts and grains 
carpel, with one seed 2 4 é : 
in place; 28. winged are provided with. Plants like the pine, 
coo (After which bear their seed in this way, are called 
Gymnosperms, a word that means ‘“ naked 
seeds,” in contradistinction to the Angtosperms, which bear 
their seeds in pods or other closed envelopes. 
Remove the coat from a seed that has been soaked for 
twenty-four hours, and examine it with a lens. Does it con- 
sist of one or more layers? Is there any difference in color 
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