tinct leaves. 
THE SEED AND ITS GERMINATION =< 
noticing that they are only attached for a very little way next to 
the hypocotyl, and observe the thickness of the halves and the slight 
unevenness of the inner surfaces. 
or cotyledons. 
These halves are called seed-leaves 
Have ready some seeds which have been soaked for twenty-four 
hours and then left in a loosely covered jar on damp blotting paper 
at a temperature of 70° or over 
until they have begun to sprout. 
Split one of these seeds apart, 
_ separating the cotyledons, and 
observe, at the junction of these, 
two very slender pointed objects, 
the rudimentary leaves of the 
plumule or first bud (Fig. 1, p). 
+3, Examination of the Bean. 
—Study the seed, both dry and 
after twelve hours’ soaking, in 
_ the same general way in which 
_ the squash seed has just been 
- examined.! 
Notice the presence of a dis- 
tinct plumule, consisting of a pair 
of rudimentary leaves between 
_ the cotyledons, just where they 
are joined to the top of the hypo- 
cotyl. In many seeds (as the pea) 
the plumule does not show dis- 
But in all cases 
the plumule contains the growing 
point, the tip of the stem from 
_ which all the upward growth of 
_ the plant is to proceed. 
_ sketch the several parts. 
“Fie. 2.— The Castor Bean and its 
Germination. 
A, longitudinal section of ripe seed; f, 
testa; co, cotyledon; c, hypocotyl; 
B, sprouting seed covered with endo- 
sperm; C, same, with half of endo- 
sperm removed; D, seedling; 17, pri- 
mary root; 7’, secondary roots; c, arch 
of hypocotyl. 
Make a sketch of these leaves as they lie in place on one of the 
cotyledons, after the bean has been split open. 
* 1The larger the variety of bean chosen, the easier it will be to see and 
The large red kidney bean, the horticultural bean, 
_ or the lima bean will do well for this examination. 
