POSITIVE D^-DOUBLEMBNT. 67 



calyx of Cniciferge and Capparidacese, the outermost 

 coroUa-wliorl of the Papaveraceous type (from Avhich 

 the Cruciferse, etc., have been derived) became trans- 

 formed into sepals, the four diagonally-placed petals in 

 Cruciferse and Capparidacese could only, as Celakovsky 

 states, have been obtained by positive dedoublement of 

 the two medianly-placed petals of the remaining (inner) 

 whorl, and not by transformation of stamens. If this 

 is so, then in the evolution of the Cruciferous flower 

 we see an interesting admixture both of reduction and 

 multiplication. 



0(0 -/' 



Fig. 86. — Bschscholtaia. Diagram of outer corolla-whorl of two (p^), 

 and inner ooroUa-whorl of four petals (p"). {Of. Crueiferse.) 

 (After Beneoke.) 



Now, Benecke describes, as an abnormality, a pre- 

 cisely similar formation of four diagonally-placed 

 petals by positive dedoublement of the two petals of 

 the inner corolla-whorl (fig. 86). But this was in the 

 Papaveraceous genus Eschschollzia, in which, of course, 

 there is also present an outer whorl of two transverse 

 petals. So that here we have occurring in actuality 

 the same phenoinenon in the very order in which it 

 was theoretically postulated by Celakovsky in order to 

 account for the origin of the corolla of Crueiferse, etc. 



In Veronica the large posterior median petal, the 

 result of the fusion of two, reverts sometimes to the 



