182 



as its base we need only add three petals, three sepals and 

 so many alae as the special case requires. This symmetry is 

 easily to be recognised in the inferior portions of the flower 

 — ovary and tube — and only the expanding parts, owing to 

 unequal development, show some deviation which has already 

 been pointed out on p. 177 and in absolute contradiction of 

 the statement of Braun (III), " die Bliite ist in keiner Rich- 

 tung symmetrisch teilbar" and the characterisation by KuaNz- 

 LiN (XII, p. 1): " Flores omnino asymmetrici". 



Symmetry attains the highest point in Dr. Smith's " third " 

 flower, because in this case the difference between labellum 

 and X is wholly absent and a and /3, being the only alae, 

 scarcely show any diff'erence. 



Explanation of deviations observed in the staminodes. 



In perusing again my descriptions of teratological cases iu 



Canna collected by Dr. Smith (XI, p. 65) some of them appear now 



in a new light and are fully understood. We wish to record 



them briefly. 



1° A specimen of Antoine Borton has two labella means that 

 the stamen is wanting and x has taken the shape of the 

 labellum. 



2° In a ''''Prof. DavicV the labellum is found replaced by a 

 stamen consequently a reversion of a staminode to the original 

 function. 



3° We have on several occasions observed three alae in those 

 varieties which have as a rule only two: a, ft and y. Dimin- 

 ution is also mentioned. 



4° Mme Crozy : two normal stamens. No labellum indicates : 

 labellum replaced by a stamen, x also, the stamen proper 

 absent. 



5° Canna hybrida, stamen altogether petaloid means : stamen 

 wanting. 



6° Canna hybrida, stamen ivith two petaloid appendages at the 

 base means that the stamen proper is absent and the ap- 

 pendages are portions of the carpellar tube. 



