276 



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 )cars ago it was thought l)y 

 some that tlris represented a different species, but now it is Icnown 



Fig. 31 S. 

 .Sensitive fern, sho\viiig one vegetative leaf and twu sporopbylts cnnipletely transfurnved. 



that these intermediate forms are partly transformed fertile lea-\-os. 

 It is a \'cry oasy matter in tlie case of lire sensiti"\'e fern to pro- 

 duce these transformations b)' experiment. If .^ne in the spring, 

 when the sterile leaves attain a height of 12 to 16 cm (S-io 

 inches ), cuts them awa)-, and again vhen the\' lia\c a second 

 time rea( liecl the same ht'iglit, some of the fViiiting leaws which 

 develop later will Ije transtbrmed, A few )ears ago I cut off the 



