SEEDS AND THEIR GROWTH 3 
against the flat surfaces. A small drop of water will ooze 
out at a point near one end of the stalk-scar, The little 
hole through which the water comes is called the 
macropyle. | 
’ The Inside of a Broad-bean Seed.—Remove the 
outer seed-coat, (testa) with a sharp knife or stout pin, 
beginning at the side 
furthest from the scar. 
Notice the colour of the 
seed coat and of the 
inner portion it encloses. 
Near the micropyle a 
little cone-shaped body 
Fig. 2.—Seed of Broad Bean, showing the will be seen—the radicle. 
two cotyledons. Examine the edge of 
a, Main stem or planus... Matn rootorradicle tho goed opposite the 
radicle and the crack 
which divides the seed into halves. Inserting the edge — 
of the knife into this crack, carefully separate the halves. 
This can be done without tearing either of them, for, 
although fitting closely together, they are really separate. 
These two swollen bodies are called cotyledons ; describe 
the shape of one of them. Make out lying between the 
cotyledons a little curved body——a continuation of the 
radicle—known as the plumule. Gently scrape the inner 
surface of one of the cotyledons and show, by pouring on 
it a few drops of iodine solution, that it contains starch. 
As it may frequently be necessary to apply what ‘1s 
known as. the “starch test,” the following experiment 
should be gone through before treating the bean seed with 
iodine solution. | 
Prepare some starch solution, by boiling a small 
quantity of starch for a short time, allowing the whole 
to cool and the undissolved starch to settle down, 
