138 



PRINCIPLES OF PLANT-TERATOLOGY. 



same thing had happened to the perianth-leaves of a 

 snowdrop (Gcdanthus nivalis) which had also become 

 erect instead of spreading, and there was no difference 

 either in shape or colour between those of the inner 

 and outer whorl. 



As in the case of the calyx, according to the degree 

 of change will be the greater or less resemblance of 

 the modified petals to the foliage-leaves of the same 



Fig. 118.— Rosa damascena (Garden Rose). Showing normal calyx (ca), 

 phyllocly of petals (p), and proliferation into a secondary flower ( ft 2 ). 

 (Ming-ay photo.) 



plant. The instances given above represent merely 

 early stages in this change, which is usually spoken of 

 as " virescence." As Masters points out, this term 

 must be also applied to such cases as that of the 

 "nasturtium" {T rojpseolum majus) in which the fron- 

 descent petals had not the peltate form of the foliage- 

 leaves, but were spathulate, though with long stalks ; 

 but in other cases their venation was more like that of 

 true leaves than of petals. The petals of Cruciferse, 

 as Tubeuf mentions, often become green and much 



v 



