THE BRACKEX FERN 



103 



more than three or four in number (Fig. 54, B). Later cell 

 divisions are in different directions (Fig. 54, C), so that the 

 young plant comes to consist not of a row but of a triangular 

 plate of cells, which as it grows becomes broader at the end 

 farthest from the old spore wall. As this small plant, which 

 is the sexual generation of the fern, continues to grow, a 

 notch appears in the forward (broader) end. 



130. The Sexual Generation. — An older sexual plant, if 

 it has not been crowded while growing, has typically the heart 



Fig. 55. — A, the sexual plant of a fern seen from below ; a, notch at the 

 f ons'ard end (the growing point) ; h, archegones ; c, antherids ; d, rhizoids. 

 B, a section through the sexual plant, showing an archegone borne on the 

 thickened part (just behind the growing point), and antherids and rhizoids 

 on the older, thinner parts. 



shape shown in Figure 55, ^4 . This plant grows very slowly 

 and remains so small that it is likely not to be noticed unless 

 we are specially looking for it. A plant a half -inch in diam- 

 eter is a large one. Its growth continues for some months, 

 and under certain conditions a plant may grow for a year 

 or more. It consists of one or two layers of green cells, 



