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THE FERN BULLETIN 



verted to the bifido-cristatitm form though curiously 

 enough, nearly every specimen bears two sorts of 

 fronds, one more finely cut than the other. The ques- 

 tion that is now puzzling Mr. Hans is, can the form 

 biiido-cHstatum change to clegantissimum. This 

 change involves a change from the forked to the 

 plumose form. Since the spores of bifido-cristatum 

 were sown by themselves, there does not appear to be 

 any possibility of accounting for the change upon the 

 ground that two forms have crossed. It appears, in- 

 deed, to be due to genuine sporting, though the forms 

 obtained are apparently indentical with specimens re- 

 garded as crosses on the other side of the Atlantic. 

 To make sure that his conclusions are properly drawn, 

 Mr. Hans has started the whole experiment over again, 

 great care being taken to exclude foreign spores in the 

 sowing. The young plants are just appearing and we 

 may expect their behaviour to throw light on the puz- 

 zle. While it is quite likely that some ferns may cross, 

 it is the opinion of Mr. Hans, that most varieties arise, 

 not through crossing but by sports. This opinion 

 seems to have received additional confirmation from 

 the experiments thus far made. 



Fertilization in Ferns. — It was not until the 

 nineteenth century, actually within living memory, 

 that the real history of the reproduction of ferns was 

 discovered. It was not possible to ascertain the facts 

 until the microscope had been improved, and the 

 methods of study of the structure of plants and ani- 

 mals had made vast progress and yielded a mass of 

 new knowledge. It was discovered in 1844 (Nageli 

 and Suminiki) that upon the under surface of the flat 

 green prothallus which develops from the fern spore, 

 two kinds of minute warts take origin. The one are 



