30 BOTANT. 



tx 



is the terminal one of a row of cells, as in many seaweeds 

 and fungi. The apical cell, in such cases, keeps on grow- 

 ing in length, and at the same time horizontal partitions 

 are forming in its basal portion. In this way long lines 

 of cells may originate. 



55. In the more complicated cases the segments cut off 

 from the apical cell grow and subdivide in different planes, 

 so as to give rise to masses of cells. The partitions which 



Fig. 20.— Longitudinal section of apex of stem of a Moss (Fontinajis antipy- 

 retica). «, apical cell ; jet. apical cell of lateral leaf -forming shoot, arising below 

 a leaf; c, first cell of leaf; 6, &, b, cells forming cortex. 



successively divide the apical cell are sometimes perpendic- 

 ular to its axis, but more frequently they are oblique to it. 

 In most mosses, for example (Fig. 20), the apical cell is a 

 triangular, convex-based pyramid, whose apex is its proxi- 

 mal portion. The successive segments are cut off from the 

 apical cell by alternate partitions parallel to its sides, thus 

 giving rise to three longitudinal rows of cells. Most ferns 

 and their relatives have an apical cell not much different 



