122 BIOLOGY 



one or two eggs, e. As these spores produce eggs, which 

 are the female reproductive bodies, we may speak of them as 

 female spores. Older botanists, before their real 

 .<&? nature was understood, called them by the name 

 of embryo sacs. The small spores (pollen) pro- 

 duced in the anther, on the other hand, are 

 spoken of as male spores, inasmuch as their 

 function in reproduction is that of the male.* 



Fertilization. The pollen grains, or male spores 

 from the anther, are carried by some means to 

 the stigma of the stamen. They are sometimes 

 carried by insects, sometimes by wind, or by 

 various other means. The stigma on the top 

 of the pistil is usually rough and sticky, and the 

 pollen grains readily adhere to it. In this posi- 

 tion, the pollen grows and a long tube arises 

 from each pollen grain and pushes its way down 

 through .the style and within the ovary; Fig. 

 65 pt. This tube is the pollen tube. In the 

 FIG. 65. meantime the female spore in the ovary has pro- 

 LONGITUDI- duced the The Uen tube ig attracted to 



NAL SECTION ,, , ,, ., ,. . .,, 



THROUGH A e ^>' a finely its tip comes in contact with 



CARPEL it. Inside of this pollen tube is found one or 



showing the more special cell nuclei which are carried in the 



teched n t<?'the tip of the growing tube and finally pass into the 



P oi- egg, fusing with it. This latter process is called 

 whic u h be 'hfs fertilization. 



though The The Seed. After the egg, which is a single 



Jen^os^dlnfhe cell, has fused with the contents of the pollen 



tube, it divides, and in a few days produces a 



little multiceilular plant. This plant, while still in the ovary of 



the pistil, develops a stem and one or more leaves; Fig. 64 sd. 



*The pollen because of the small size, is also called a microspore, and 

 the spore in the ovary, being larger, is called a megaspore or macrospore. 

 The significance of this we shall notice in a later chapter. 



