Metamorphosis. 



177 



In Miltonia the cause of the extra corolla-members 

 was in part an increase in the number of whorls {i. e. 

 positive d^doublement) . 



In Iris Ksempferi and I. Sieboldii, in which other 

 reversionary changes, as already described, had taken 

 place, one or two of the stamens of the inner whorl 

 (usually absent) had become petaloid or partially so. 

 In abnormal orchid-flowers, as seen in the above-cited 

 instances, some of the stamens, which are normally 

 absent, tend to reappear under a similar guise. 



@ 



Fig. 131, —Cypripedium Sedeni. Diagram of flower showing four super- 

 numerary labella. lb, normal labellimi ; W, extra labeUa. 



The case of the Iris is somewhat exceptional in 

 another way, viz., that when two whorls occur, it is 

 more commonly the stamens of the outer whorl which 

 are the first to become petaloid ; and this, of course, is 

 only what should be expected, seeing that they are in 

 proximity to the petals which are themselves petaloid 

 stamens. 



Bichler and F. Miiller observed in the Al]iinia luon- 

 tioned in a previous section, the transformation of the 

 normally fertile posterior stamen of the inner whorl 

 into a labellum, resembling the normal one in the 



VOL. II. 12 



