3.6 ■. .BOTANICAL GAZETTE - [july 



while only one cell wide^ and that the first division in each cell is 

 periclinal and cuts off the potentially sporogenous cells from' the ones 

 destined to form wall and tapetuni. The outer segments, according 

 to Bower, by repeated division add considerably to the sporogenous 



tissue. It is soecificallv stated 



and 



implied by Campbell, that the tapetum arises from the outer part of 

 the sporogenous tissue. 



pendulu 



pendul 



GoEBEL and Rostowzew. 



Later stages 



ment 



material 



be taken up conveniently under three heads: the w^all, the tapetum, 



HELMINTHOSTACHYS AND BOTRYCHIUM 



In Botrychium virginianum Holtzman figures the sporangium as 

 arising from a single celL Writing of Helminthostachys, Bower 

 says: *^The sporangia are similar in origin and mature structure to 

 those of Botrychium, the essential parts being referable to a single 

 superficial cell, of which the first periclinal division defines the spo- 

 rogenous from the protective parts." In agreement with Russow he 

 thinks that in at least some species of Botrychium the archesporium 

 may consist of more than one cell. Goebel and Cardiep think the 

 archesporium in B. lunar la and in B. virginianum is one-celled. 

 Campbell likewise thinks that the archesporium of Botrychium is a 

 single cell and that the entire sporangium is referable in origin to this 

 one superficial cell. He ascribes the origin of the tapetum partly to 

 the wall and partly to the outer sporogenous tissue. Goebel figures f 



it arising from the wall and sterile cells surrounding the sporogenous 

 tissue. Cardiff also is positive that it comes wholly from the wall 

 and tissue outside of the sporogenous mass. In Helminthostachys 

 Bower has shown that the sporangium originates from a single super- 

 ficial cell, that there is a single primary sporogenous cell, and that the 

 tapetum arises from the wall. 



sporogenous 





