2l6 



BOTANICAL GAZETTE 



[SEPTEMBER 



shifted from a marginal to a ventral position, and finally stands at 

 nearly a right angle to the plane of the lacinia. 



As stated above, the initial cell of the sporangium appears near the 

 apex of a fertile portion of the leaf (figs. 7, 5, p). A part of one of the 

 segments of the apical cell enlarges and an oblique wall cuts in, either 



II 



Fig. 5. The ventral side of a pinnule showing that the sporangia are soon covered 

 by the indusium. X 130. — Fig. 6. The dorsal side of a pinnule showing the sporangia 

 not covered by the indusium, X 190. — Fig, 7. The apex of a pinnule showing an 

 initial sporangial cell. X980. — Fig. 8. A longitudinal section of a pinnule showing 

 the apical cell and a sporangial initial. — FiG. 9. An initial cell, s; and the beginning 

 of the indusium, a.— Fig. 10. The first division of the initial cell, the first wall coming 

 in on the anterior side, a, initial cell; i, first cell cut off. X980. — FiG. 11. The first 

 division of the initial cell, the first wall coming in on the basal side. X980. — Fig. 12. 

 A section showing the first and second cells cut off from the initial cell. X980. 



fig^ 



A second wall 



pposite 



upon the first (fig. 12 

 upon the second {figs 



These 



term 



SU' 



