450 BOTANICAL GAZETTE [decembek 



increasing rapidly in size. The microsporangia arise in basipetal 

 succession, have long slender stalks, and each sporangium develops 

 sixteen spore mother cells- As the growth of the stalks in length 

 and of the capsules in size continues, there is a consequent broadening 

 of the sporocarp, which makes of the mature microsporocarp a round 

 body, quite different from the more elongated megasporocarp. By 



4 



the time the oldest of the microsporangia have reached the mother- 

 cell stage, the megasporangium has usually collapsed, so that unless 

 one happens to get a median section of the sporocarp {iigs. ii, iia) 

 it is likely to escape notice. How^ever, I found several microsporo- ■ 

 carps in which this collapse of the megasporangium did not occur. 

 In these cases the cytoplasmic contents of the megasporangium had 

 broken down and had to a large extent been resorbed, but the spo- 

 rangium wall remained turgid, while the cells of the stalk at the base 

 of the sporangium had grown up into the cavity left by the breaking- 

 do w^n of the cytoplasm {figs. 12, ij). In one case {fig, if) this growth 

 had continued until the sporangium was nearly filled with vegetative 



tissue* 



DISCUSSION 



While Griffith, in 1844, interpreted the megasporangium as a 

 male organ and the microsporangia as female organs, as R. Brown 

 and Meyen had before him, he gave an accurate account of the 

 order in w^hich the various structures of the sporocarp appear. Since 

 the appearance of Strasburger's Ueber Azolla, writers seem largely 

 to have overlooked Griffith's work. Doubtless this is due to. the 

 fact that Strasburger, who worked largely on the very early and , 



the mature stages of the development, without catching the inter- 

 mediate stages, suggested that probably Griffith's account would 

 not hold true, since it seemed more probable that the sporangia would 

 appear simultaneously in the megasporocarp as they did in the micro- 

 sporocarp. It is interesting to note that sixteen years after Ueber 

 Azolla appeared, Strasburger again gave an account of Azolla, in 

 which he affirms that the primordia of the two sporocarps are alike, \ 



ment of a megasporangmm 



w 



hich 



r% 



microsporocarp soon aborts. It is evident that he no longer 



sporangia in the micros 



simultaneous, and so his former inference, that probably the mega- 



