MEMBERS OF THE PLANT BODY 323 
nature lead us to inquire; What is the fundamental plan of 
structure exhibited by our typical plant? and What may we 
rightly regard as the members of such a plant-body? 
98. Morphological units. We have seen that the embryo 
flax is a miniature plant already possessing a stem-part, 
rudimentary leaves, and the beginning of a root. These parts 
we recognize as representing the main divisions of the plant, 
at least before it. flowers, for we know that for many weeks 
as the plantlet grows it simply produces more root, more 
stem, and more leaves. If we examine minutely one of 
the leaf-buds (Fig. 280) we find it to contain a series of 
young leaves which are smaller and smaller as we approach 
the tip of the stem until finally they appear as mere lobes. 
Thus we see that a leafy shoot begins as a tiny dome- 
shaped mass of growing material, which as it elongates, be- 
comes differentiated into (1) lateral lobes, which grow into 
leaves, and (2) a central or axial part constituting the stem 
which bears them. Soon in the axils of the young leaves 
appear growing points like the cone at the tip, and each 
of these becomes a bud which may develop into a leafy 
branch. Since corresponding parts arise at regular intervals, 
the whole shoot, especially as it grows older, takes the form 
of a series of segments or equivalent divisions each consisting 
of a leaf-part borne by a stem-section from which a bud or 
rudimentary branch may also develop. The embryo, we 
remember, had just these parts, and in addition bore a root. 
Often, such a shoot-segment cut from a plant and placed 
under favorable conditions for growth will send out a root, 
and develop other segments much as an embryo does; and, 
commonly, a cutting which consists of a single leaf attached 
to a bit of stem, is the least part of a flowering plant that 
can be made to grow independently. Hence such a seg- 
ment consisting of an internode and its node, together with 
the leaf or leaves it bears, has been regarded as constituting, 
in a way, a unit of plant structure. 
99. Members of the plant body. A plant like flax is some- 
times thought of as a colony of segments or in other words 
as a community of closely connected individuals each con- 
sisting of a stem-part and leaf-part, and capable of producing 
