2l8 



BOTANICAL GAZETTE 



[SEPTEMBER 



The fourth division cuts off the cap cell (figs.^is, i6), which in 



J 



longitudinal section perpendicular to the leaf surface appears as 

 an arch over the central cell {fig. 17). This is the longest axis of the 



cap cell. 



The stalk.— The stalk is short and thick {fgs. i8, iq), the first 



« 



Fig. 21. The first division of the central cell. X980.— Fig. 22. The third division 

 of the central cell to form the third tapetal cell. X980. — FiG. 23. The young sporan- 

 gium after the three tapetal cells have been cut off. — FiG. 24. Anticlinal walls in the 

 tapetum. — FiG. 25. The first periclinal division in the tapetum. — Fig. 26. A later 

 stage in the development of the tapetum. 



sporan; 



(fig 



Fig. 20 



shows that the adjoining cells also contribute to the stalk. 



The tapetum. 



tapetum is cut off from 



{h 



