REPRODUCTION 109 
ing glory vine, bamboo, etc., it can be measured every day with 
aruler. Make and record such measurements night and morn- 
ing for several kinds of plants. 
154. Reproduction. This is the ultimate function of 
all plants. For many itis the final function of life, the 
death of the old individual occurring with the formation 
of the new individual. Itis perhaps to be considered as 
the final act of growth toward which all development 
of the plant has been leading. 
155. In many of the lower plants, especially those 
that are undifferentiated, reproduction is nothing more 
than cell division followed by separation of the cells thus 
produced. In the more differentiated plants, however, 
we find certain cells set aside for reproductive purposes. 
These may be at first ordinary vegetative “cells that 
later take up the reproductive function, or they may be 
destined for the latter from their beginning. 
156. Very early in the vegetable and animal kingdoms 
two types of reproduction become recognizable, the 
asexual and the sexual. The former consists essentially 
of the division of the plant, or of the separation from it 
of single cells or groups of cells or even whole plant 
members. By further growth these parts thus pro- 
duced become like the parent plant. Not to be confused 
with true asexual reproduction, is the development 
of the gametophyte orn the spores produced by the 
sporophyte. 
157. Sexual reproduction is fundamentally different 
from asexual reproduction in that there is requisite the 
union of two distinct cells (or at least their nuclei) to 
form a single cell, the zygote. This may develop 
directly into a new plant or into a mass of cells (the 
spore fruit), which produces only eventually the repro- 
ductive cells, which give rise to the new plants. The 
