18 INTRODUCTION TO BOTANY 
upward from it; in others the seed coat is carried upon the 
seed leaves until they appear above the surface of the ground, 
when by the spreading of the seed leaves the coat is dropped 
(fig. 13). Some kinds of plants have one seed leaf, as in 
corn; while others, as the sunflower, have two seed leaves, 
between which the first 
true leaves appear. 
15. Further study of 
the parts of a plant. It 
must be evident from 
the discussion in this 
chapter that a plant is 
Fie. 18. Seedlings of the 
sunflower plant 
A, old seed coat still partly 
inclosing the seed leaves; 
B, seed leaves open and first A, leaves unfolding; B, leaves and other parts 
true leaves appearing well developed 
Fie. 14. Young corn plants 
a sort of machine consisting of roots, stem, leaves, flowers, 
and seeds. By means of this plant machine raw materials 
are secured and manufactured into plant food. This manu- 
factured food is distributed through the plant; some of it is 
used immediately and some of it is stored. Seeds are manu- 
factured, and by means of them new plants are started on 
their round of activities. Having in this chapter merely out- 
lined the nature of the plant machine and the work done by 
