129 



cannot take the place of the second labellum enclosed as it is 

 by its two neighbours. 



Only in normal flowers one of the alae may sometimes be 

 enlarged and become somewhat labellum-like. T have noticed 

 this phenomenon twice in y, once in ft. 



This conclusion has been corroborated by a communication 

 from Dr. Smith stating that in November 1918 he had found a 

 „third" flower with two labella and 3 staminodes, consequently 

 a case which tallies exactly with the ordinary diagram and in 

 which the only alteration consists in the stamen having become 

 petaloid. 



The present examination of Canna has produced an additional 

 result, viz., the morphological value of a, ft and y. It appears 

 that the two labella in our monstrous flowers (and the same 

 thing is shown in the normal) tend to contract their base and 

 to roll it into a kind of tube. From the edges and the tube 

 itself there spring one or more lobes which Eichler calls 

 "Stipulargebilde' 1 . The same thing is shown more or less distinctly 

 by the other staminodes also. All these lobes resemble one 

 another by their origin, viz., from the inner side of the staminodes. 



The alae themselves on the other hand are always produced 

 on the outer side of the stamen whether this be transformed 

 or not. They are consequently of a different kind and not to 

 -be classed with Eichler's "Stipulargebilde". Hence I am led to 

 abandon my former opinion ') as to their significance and 

 henceforth to look upon the alae as real staminodes and 

 accordingly to adhere to Eichler's diagram in which he re- 

 presents an outer whorl of two and an inner one of three 

 staminodes. 



Orchidaceae. 



Aerides odoratum Lour. 



1) Ann. do Buitenzorg. Vol. XTIT, p. C>3. In this paper we have already registered 

 instances of the stamen transformed into a labellum. 



