460 . BOTANICAL GAZETTE [December 



latter stage. The mitosis may take place before the sporeling 

 begins to elongate; but in the majority of cases the sporeling 

 elongates into a somewhat pear-shaped structure while its nucleus 

 is still in the resting state (fig. 108). Quite often the nucleus is 

 present at the elongated portion (fig. 109). The cell wall of the 

 elongated portion which is to become the holdfast is comparatively 

 thick. 



The number of chromosomes at prophase (figs. no 7 in) and 

 seen in polar view at metaphase (fig. 114) is 48. The axis of the 

 figure is often perpendicular to the growing axis of the sporeling 

 (fig. 113). After telophase the sporeling is 

 (fig. 115). The nuclei of the two cells divi 

 sometimes the lower nucleus increases more 



divided 



(fig. 117) 



mitosis 



order in the three nuclei; 



may 



may divide simultaneously 



(fig. 123). The number of chromosomes appearing at the prophase 

 (figs. 121, 123) is 48. 



The fourth, fifth, and subsequent divisions, that occur continu- 

 ously for more than ten days, multiply the number of the cells of 

 the sporeling, resulting in the development of the upright columnar 

 form that grows standing upon the substratum, and then the 

 direction of growth becomes changed. 



Before describing this change of growth which occurs in spore- 

 lings about ten days old, we shall note briefly the fate of the red 

 pigment that is conspicuous in the living gametes. As was stated 

 before, the red pigment is always associated with the plastid. A 

 part of the plastid becomes impregnated with some substance of a 



disorg 



death of the sporeling. The most 

 cilia are attached to the pigment, and the red pigment is the only 

 structure within the sporeling that bears any close and direct 

 physical connection with the cilia. Moreover, the plastid that 

 bears the red pigment always lies near the nucleus. By the union 

 of male and female gametes the red pigment bearing plastid of the 

 male gamete is introduced into the female eamete and consequently 



