POSITIVE D:fiDOUBLKMBNT. 



83 



A^ was fertile, while the two normally fertile stamens 

 of the inner whorl {a^ and a^) were staminodial. In a 

 flower of G. Spicerianum all the three stamens of the 

 inner whorl {a^, aj and a^) were present and fertile. He 

 also observed a tetrandrous flower of G. Lairrenceantim 

 which was composed as follows : Aj (the usual stami- 

 node), a^, a^ fertile, and 03 developed as a lip which lay 

 within the normal lip. Hexandrous flowers occurred 

 in a G. Sedevi, all six stamens being present ; Aj and 

 f/3 were fertile, while all the rest were in the form of 

 saccate lips (fig. 94). 



Rolfe mentions a flower of Gattleya labiata which had 



Fiu. 94. — Gypripedium Sedeni. a. Column showing presence of stamen 

 a^ of the inner whorl, h. Diagram of the same flower. (After 

 Masters.) 



three fertile stamens, but the lip was developed as an 

 ordinary petal ; thus the flower reverts to regularity. 

 It is very rare for the posterior stamen of the inner 

 whorl ((Xg) to be developed, but an example is afforded 

 by Uropedium (merely a peloriate form of Pachypedilum 

 cavdatum) ; therefore in this all three stamens of the 

 inner whorl are fertile. Another instance has just 

 been cited in G. Sedeni. 



The interest of the above facts lies in the reversion, 

 for the most part partial, which they exhibit to the 

 ancestral structure. 



Positive dedoublement in the above instances takes 

 the form of the reappearance of vanished members. 



In abnormal flowers of the polyanthus narcissus 



