143 



of these types, however, showed great varial)ility both in the 

 size of the plant and the spores, and also to some degree a 

 difference in the shape of the sterile segment. It is not unlikely 

 that more than two species are present. As the different forms 

 generally grew more or less mixed together, there was neces- 

 sarily some doubt as to the identity of all specimens ot 

 germinating spores that were examined. It was found, however, 

 that the coarsely reticulate spores, presumabl}^ belonging to 

 the typical species, germinated more freely, and probably most 

 of the germinating spores that were studied l)elong to this 

 species. The largest spores came from the large cordate leaved 

 form, but no success was had in germinating these. 



The first sowings of the spores were made on March 13th. 

 These were examined a week later, and a large part of them 

 were found to be germinated, the young prothallia having two 

 or even three cells. Sowings made on March 26th had begun 

 to germinate three days later, and by March 31 showed many 

 two-celled stages, and some which were doubtfully three-celled. 

 The exospore bursts, as usual, along the three radiating lines 

 of its ventral surface, and the enclosed endospore protrudes 

 through the cleft, the three lobes of the exospore being forced 

 widely apart. The projecting portion of the spore contents has 

 somewhat less granular matter in it than the portion within 

 the spore membrane, but it is not narrowed at all, and does 

 not seem to be a proper rhizoid, as it never becomes elongated. 

 Shortly after the bursting of the spore coat the projecting 

 portion becomes shut off by a transverse wall (Fig. 2). The 

 upper cell is somewhat smaller as a rule, and contains much 

 less granular matter; but as already stated, it does not become 

 elongated and while it is perhaps the equivalent of the first 

 rhizoid of the leptosporangiate fern, it never assumes the 

 form of a proper rhizoid. Owing to the dense cell contents, 

 the large central nucleus of the fern is not very clearly 

 discernable, although its position can be easily made out. The 

 outer cell wall becomes more or less distinctly thickened. 



Ordinarily the next division, as in 0. penduhnn (Campbell 



