11(1 



PLANT STUDIKS 



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 reproduclion. These spores are very simple 

 bodies, but have the jiower of producing new individuals. 

 There are two great groui^s of spores, diilering 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 

 jiarent ; in the other 

 case two special bodies 

 of tlie parent l)lend 

 together to form the 

 spore. Although the}' 

 are both spores, for 

 convenience we may 

 call the first kind 

 spores (see Figs. lOG, 

 100), and the second 

 kind cfjgs (see Fig. 

 107).* The two sjiecial 

 liodies which lileud to- 

 tjether to form a.ii effg 

 are called gameten (see 

 Figs. 107, lo,s, lOD). Tliese terms are necessary to any 

 discussion of the external relations. Most plants develop 

 both spores and eggs, but they are not always equally con- 

 s])icuous. Among the alga^ both spores and eggs are i)rom- 

 iuent ; among certain fungi the same is true, liut many 

 fungi ai'o not known to produce eggs ; among moss-phmts 

 the si)ores a.re prominent and abundant, but the egg is 

 conceale(l a.nd not generally noticed. AVliat lias l)eeu said 



•'" II is rccoij'iuzed that this spore is i-cally a. fertilized egg, but in 

 tlic abseiici' of any accurate simple word, the term egg is used for con- 

 venience. 



Fli;. 107. Fr.lgments of a common alga {Sin- 

 rogyrii). Portions of two threads are shown, 

 wliicli have been joined together l)y the grow- 

 ing of connecting tubes. In tile upper thread 

 four cells are shown, three of which contain 

 eggs (,:), while I ho cell marked g, and its mate 

 of the other Ihroad each contain a gamete, 

 the Ir.wir niii' of whii'h will pass through the 

 tiilie, hli-iid with the upper one, and form 

 another egg. 



