REGENERATION IN PLANTS 8? 



end grows out and produces a new sporangium. If pieces of the 

 stem are cut off and placed in a nourishing medium, they produce 

 from the ends a new mycelium, and from this new erect hyphae may 

 develop. In the former case, the cut-end regenerates the part 

 removed in somewhat the same way that an animal regenerates at the 

 cut-end ; in the latter, there is a return to the mycelium stage, as in 



FlG. 36. After Goebel. Achimenes Haageana. A leaf-cutting of a plant in flower. The new 

 plant, regenerating at base of leaf-stalk, proceeded at once to produce a flower. 



the piece of the moss that produces a new protonema. If the my- 

 celium and the protonema are looked upon as an embryonic stage in 

 the formation of the sexual form, there is a return in these cases to an 

 embryonic form or mode of development. 



One of the most remarkable and important discoveries in con- 

 nection with the regeneration of plants is that the new individuals that 

 develop from leaves cut off from certain plants differ according to 



