193 



bearing developed sporangia and spores, + thus cutting out 

 the sporophyte, and reducing the life cycle to spore, 

 prothallus, spore, an absolute minimum. I must refer to 

 Mr. Lang's papers for the most interesting details of these 

 and other vagaries, and will merely add that on one and 

 the same prothallus several different modes of reproduc- 

 tion were found, namely, asexual bulbils, some producing 

 fronds and others merely roots, other prothalli budding 

 out from the surface, and sporophytes sexually developed, 

 all these on prothalli which themselves were thick cylin- 

 drical fleshy masses instead of the normal flat cordate 

 thallus, while archegonia, antheridia, and sporangia were 

 indiscriminately dotted about among the other varied 

 growths. 



The above facts are cited merely as a prelude and justi- 

 fication for the suggestion that in the study of American 

 species the varieties should have due attention and not be 

 labelled "monstrosities," and ignored as they were in 

 Great Britain for a very long period. The writer has 

 repeatedly urged and urges once more that it is quite as 

 much, if not more, in the direction of nature's exceptions 

 that we should seek the key to many of her secrets. 

 Certainly in the study of the abnormal fern types alluded 

 to, a number of new and unexpected facts have cropped 

 up, which largely modify previous ideas regarding fern 

 reproduction, not one of the links in the normal life cycle 

 being absoutely essential. Spore, prothallus, egg, sporo- 

 phyte, have all in turn been shown to be superfluous, the 

 fern in one shape or another reproducing itself without 

 them. 



As regards the great number of varietal forms which 

 have originated in Great Britain, there is little doubt that 



f Lang, W. H. : Proc. Roy. Soc. 63: 56-61. Phii. Trans. Roy. 

 Soc. Ser. B. 190 : 1S7-238. 1898. 



