K 



* 



it-' 





*907] PFRIFFER—SPOROCARPS IN AZOI.LA 451 



sporocarp is like the microsporocarp in this particular, no longer has 

 any weight. 



Campbell, writing four years after the appearance of Stras- 

 burger's second paper, has evidently not given close attention to 

 this later account of the development, or he might have been led to 

 make a more careful study of the columella, which he found in all 

 his preparations of the microsporocarp. That this columella actually 

 represents an abortive megasporangium seems not to have occurred 

 to him, although Strasburger's paper would have suggested it. 

 The nearest approach that I found to such a columella as Campbell 

 figures was in the few cases where the vegetative cells of the stalk 

 had grown up into the cavity left by the collapse of the cytoplasmic 

 contents of the megasporangium {iigs. 12^ ij). Any section, except 

 the median, of such a sporangium as that shown in 'jig. 13, would 



show 



m 



■ 



but the median section 



shows very clearly the remains of the broken-down cytoplasm and 



nuclei. 



megasporan 



in the microsporocarp and then aborting, the interpretation of the 

 sporangial primordia about the base of the megasporangium in the 

 megasporocarp as micro sporangia is natural. Campbell, having 



missed 



sporan 



megaspora 



He over- 



more nearly simultaneous than in AzoUa. 



sporangia 



portray 



course of events as I saw it. Yet even he accepts Strasburger's 

 statement that the abortion of the megasporangium in the microsporo- 

 carp occurs early. While at first sight this would seem to be the 

 natural course of events, abortion after the formation of the mega- 

 spores really carries the reduction in the megasporangium only one 

 step farther than in the megasporocarp. Long ago Strasburger 

 saw cases in the megasporocarp where two spores developed while 

 thirty aborted. This condition, which I have seen a few times, was 

 readily looked upon as a reversion to the condition in which more 

 than one spore developed in the megasporangium. The abortion 



