242 



emitted from what was the upper but is now the lower 

 surface. 



Dec. 8. — The root-hairs which were visible a month ago 

 on one of the pinnulets from prothallus No. 1, which was 

 not in contact with the soil, have perished. Those in 

 contact with the soil are living and presumably rooted, 

 but very little growth is now going on. 



Summary of Results of Experiment. 



(1) The fact that detached portions of frond from a 

 deciduous fern can be kept alive for over eighteen months 

 is a little remarkable. Had they been left on the parent 

 plant they would undoubtedly have perished the first winter. 



(2) Influence of environment on the development. 



(3) The rapidity and energy with which the isolated 

 protoplasm breaks out when once the tendency to branching 

 has been exhausted and a free cellular tissue produced. 



(4) The variety of ways in which this occurs, viz. : — 



(1) Gemmation from the rachis without pro- 

 duction of prothalli. 

 1(2) (a) Apogamic buds from the prothallus. 

 (6) Normal sexual axes of growth from 

 prothallus. 



(5) The ease with which apospory is induced in the 

 primary fronds as compared with the extreme difficulty in 

 the case of the adult fronds is characteristic of all aposporous 

 ferns, so far as I know. I have at various times succeeded 

 in raising plants by apospory from eight different ferns — 

 four forms of Polystichum angulare, one of Lastrea paleacea, 

 and three of Athyrium Filix-foemina ; and in every case I 

 have noticed that if the first fronds from the prothallus were 

 pinned down (and, indeed, frequently without this special 

 treatment), the edges rapidly developed into prothalli. 



