CHAPTER VI 
REPRODUCTIVE ORGANS 
IT will be remembered that nutrition and reproduction 
are the two great functions of plants. In discussing 
foliage leaves, stems., and roots, they were used as illustra- 
tions of nutritive organs, so far as their external relations 
are concerned. We shall now 
briefly study the reproductive 
organs from the same point 
of view, not describing the 
processes of reproduction, but 
some of the external relations. 
71. Vegetative multiplica- 
tion. Among the very lowest 
plants, no special organs of 
reproduction are developed, 
but most plants have them. 
There is a kind of reproduc- 
tion by which a portion of 
the parent body is set apart to 
produce a new plant, as when 
a strawberry runner produces 
a new strawberry plant, or 
when a willow twig or a grape 
cutting is planted and produces new plants, or when a potato 
tuber (a subterranean stem) produces new potato plants, or 
when pieces of Begonia leaves are used to start new Begonias. 
This is known as vegetative multiplication, a kind of repro- 
duction which does not use special reproductive organs. 
109 
B 
FIG. 106. A group of spores : 
spores from a common mold (a 
fungus), which are so minute and 
light that they are carried about by 
the air ; B, two spores from a com- 
mon alga (Ulothrix), which can 
swim by means of the hair-like 
processes ; C', the conspicuous dotted 
cell is a spore developed by a com- 
mon mildew (a fungus), which is 
carried about by currents of air. 
