2 7 6 



MORPHOLOG Y. 



leaves, the general plan of which is the same, and we recognize 

 each as being a leaf. 



566. Transformation of the fertile leaves of onoclea to 

 sterile ones. It is not a very rare thing to find plants of the 

 sensitive fern which show intermediate conditions of the sterile 

 and the fertile leaf. A number of years ago it was thought by 

 some that this represented a different species, but now it is known 



ern, showing one vegetativ 



Fig. 318. 

 : leaf and two sporophylls completely transformed. 



that these intermediate forms are partly transformed fertile leaves. 

 It is a very easy matter in the case of the sensitive fern to pro- 

 duce these transformations by experiment. If one in the spring, 

 when the sterile leaves attain a height of 12 to 16 cm (8-10 

 inches), cuts them away, and again when they have a second 

 lime reached the same height, some of the fruiting leaves which 

 develop later will be transformed, A few years ago I cut off the 



