STRUCTURE 
secutively with Arabic numerals. Let your initials ap- 
pear in one corner of each card. Do not write on the 
cards with a soft pencil. Read the introductory chapter 
of Stevens’ Botany, pages 1-4, and Leavitt's Botany, 
pages 244-245. See also Ganong’s Teaching Botanist, 
page 165. 
As soon as you have completed your drawings ask 
the instructor to criticise them. Do this with all future 
drawings, unless otherwise advised. 
Structure—Study several soaked beans. What effect 
did the water have on their size, form, and surface mark- 
ings? Remove the seed-coats, two closely united. The 
outer is called the testa and the inner the endopleura; de- 
scribe both. Are the markings seen on the surface of the 
dry bean, in the testa or the endopleura? What relation 
does the chalaza, the hilum and the micropyle bear to the 
testa? All that is left of the bean after the seed-coats 
are removed is called the embryo. It is composed of 
two large parts, the cotyledons, a root-like structure, the 
radicle, and a small bud of leaves, the plumule. Describe 
each in detail. Are both cotyledons attached to the 
radicle? What is the relation in position between the 
point of the radicle and the micropyle? Is the testa in 
any way modified near the distal end of the radicle? 
How many leaves do you find in the plumule? How 
are they folded? Demonstrate this to the instructor by 
cutting and folding pieces of paper to represent the 
leaves. | 
Make a drawing (x2) that will show the plumule, 
radicle, and one cotyledon in their natural position. 
From the study of the bean it will be seen that the 
