154 



PRINCIPLES OF PL ANT- TE R A TO LOCI Y . 



two innermost having been transformed into two 

 short thick stamens. This is exactly what has occurred 

 normally in Boceonia, but in this plant the outer whorl 

 of petals has become similarly transformed, so that 

 this genus is normally apetalous. 



A very interesting case in the foxglove (Digitalis 

 purpurea) has lately been described and figured by 

 Miss E. Saunders, and the present writer has also 

 seen specimens from the same source. In some plants 

 all the flowers were devoid of a corolla ; in the 

 extreme cases all five petals were changed into stamens, 



Fig. 123. — Digitalis purpurea (Foxglove). Flower showing staminody 

 of petals {p). s, normal stamens. 



so that such flowers were ennean droits ; but the most 

 frequent were those in which only the three petals 

 of the lower lip were so changed, yielding hept- 

 androtts blooms ; also intermediate forms occurred 

 between these two (PI. XLIII, figs. 3 and 4, and 

 fig. 123 in text). 



Eichler observed that the spurred petals in Aquilegia 

 had become changed back into stamens. Their normal 

 form is sufficient indication of their erstwhile staminal 

 origin, and this abnormal change in the opposite 

 direction is merely a substantiation of that idea. 



Celakovsky observed that in Geratocephalus ortho- 

 ceras and the mouse-tail (Myosurus minimus) 1-3 of 

 the five petals had become changed into stamens, 



