XIX] 



LEPIDOCABPON 



273 



up from the sporophyll, forming an integument which overtops 

 the apical ridge of the sporangium, leaving a narrow micropyle in 

 the form of a long crevice (m, fig. 218, B). At the proximal end 

 of the sporangium the integument forms an enclosing wall ; at 

 the distal end it abuts on and is continuous with the upturned 

 end of the sporophyll. It is clearly established by Scott that the 



Fio. 218. Lepidocarpon Lomaxi, Scott. 

 A and C. After Scott. 

 B. Diagram of a single sporophyll : m, micropyle ; St, stele. 



tissue which invests the sporangia is not the upturned margins 

 of the sporophyll, but a new formation fully entitled to the 

 designation integument. It is noteworthy that the integument is 

 not developed until a late stage in the ontogeny of the strobilus ; 

 it is not formed until after the production of the prothallus^ 



1 Letter from D. H. Scott (March 30, 1908). 



