110 
PLANT STUDIES 
72. Spore reproduction. Besides vegetative multiplica- 
tion most plants develop special reproductive bodies, 
known as spores, and this kind of reproduction is known 
as spore reproduction. These spores are very simple 
bodies, but have the power of producing new individuals. 
There are two great groups of spores, differing from each 
other not at all in their powers, but in the method of their 
production by the parent plant. One kind of spore is 
produced by dividing 
certain organs of the 
parent ; in the other 
case two special bodies 
of the parent blend 
together to form the 
spore. Although they 
are both spores, for 
convenience we may 
call the first kind 
spores (see Figs. 106, 
109), and the second 
kind eggs (see Fig. 
107).* The two special 
FIG. 107. Fragments of a common alga (Spi- 
rogyra). Portions of two threads are shown, 
which have been joined together by the grow- 
ing of connecting tubes. In the upper thread 
four cells are shown, three of which contain 
eggs (z), while the cell marked <?, and its mate 
of the other thread each contain a gamete, 
the lower one of which will pass through the 
tube, blend with the upper one, and form 
another egg. 
bodies which blend to- 
gether to form an egg 
are called gametes (see 
Figs. 107, 108, 109). These terms are necessary to any 
discussion of the external relations. Most plants develop 
both spores and eggs, but they are not always equally con- 
spicuous. Among the algae, both spores and eggs are prom- 
inent ; among certain fungi the same is true, but many 
fungi are not known to produce eggs ; among moss-plants 
the spores are prominent and abundant, but the egg is 
concealed and not generally noticed. What has been said 
* It is recognized that this spore is really a fertilized egg, but in 
the absence of any accurate simple word, the term egg is used for con- 
venience. 
