The dishes containing the soil were also sterilized in the same 

 way. All of the cultures were supplied with a l / A pro mille 

 normal nutritive Solution, and were kept at a temperature 

 varying between 19 — 21 ° C. 



4. EXPERIMENTAL. 



In course of my investigations the following species were 

 used : 



1. Mnium rostratum Schwagr. 



2. Funaria hygrometrica Hedw. 



3. Bryum capillare Hedw. 



4. Bryum argenteum Linn. 



5. Barbula muralis Timm. 



6. Atrichum uudulatum P. Beauv. 



7. Polytrichum commune Linn. 



8. Brachythecium rutabulum Nob. and variety. 



9. Leptobryum pyriforme (L.) Schimper. 



10. Phascum cuspidatum Schreb. 



11. Ceratodon purpureus Brid. 



12. Fissidens bryoides Hedw. 



In addition to these, cultures of Plagiochila asplenoides 

 and Lophocolea bidentata were made for comparison with 

 those of Schostakowitsch. 



MNIUM ROSTRATUM. 



Mnium on account of the size of its leaves and the con- 

 sequent ease of manipulation presents a very favorable spe- 

 cimen for experimentation. In its power and manner of re- 

 generation it Stands alone among all of the species investigated. 

 At first two cultures were made for exposure to light; the 

 leaves were carefully stripped from the stems and in one case 

 placed with the dorsal surfare upper most, in the other with 

 the central surface upper most. These cultures were placed 



