GERMINATION.—ORGANS OF THE PLANT. 13 
while the upper part elongates upwards, carrying the plumule 
with it, and at the same time the cotyledonary portion becomes 
developed and forms the first leafy organs. This development 
of the embryo is termed germination ; the office of the coty- 
ledonary portion is, however, only of a temporary nature, 
being simply designed to afford nutriment to the rudimentary 
parts of the future plant in the early stages of their growth ; 
but by the development of the central axis in two opposite 
directions we have formed a lower portibn which is called the 
descending axis or root (fig. 18, 7), and an upper part termed 
the ascending axis or stem. Upon this ascending axis or its 
Fig. 18. Fie. 19. 
Fig.18. Germination of the Haricot or French Bean, a Dicotyledonous plant, 
7. The roots, springing from the lower end of the axis, ¢ (tigellum). c, c. 
The cotyledons. d, d. The leaves. Fig.. 9. Germination of Maize, a 
Monocotyledonous plant. ¢. The axis, giving off roots from its lower 
extremity. c. The cotyledon. g. The leaves and young stalk. 
divisions all the future organs of the plant are arranged ; those 
which immediately succeed the cotyledons, c, c, constitute the 
first true leaves of the plant, d, d ; and all which succeed the 
leaves in the order of development, such as the flower and its 
parts, are merely modifications designed for special purposes of 
those organs which have preceded them. Hence these three 
organs, namely, root, stem, and leaves, which originally exist 
in the embryo in a rudimentary state, or are developed as soon 
as germination commences, form the fundamental organs of the 
plant. They are commonly called organs of nutrition, because 
they have for their object the nutrition and growth of the 
plant to which they belong ; while the flower and its parts, 
