hood slips off on either side, according as the bee sucks either nectary. 
. Now I have examined several flowers of C. tuberosa, in which 
both nectaries were equally developed and contained nectar, and in this 
we see only the redevelopment of a partially aborted organ; but with 
this redevelopment the pistil becomes straight and the hood slips off in 
either direction; so that these flowers have acquired the perfect struc- 
ture, so well adapted for insect agency of Dielytra and its allies.” 
A similar case is mentioned by Hornung,* in which C. pumila, Host., 
presented two spurs, instead of one only, and thus ee Dicentra 
and Adlumia, which always have two. 
ExpLanation OF Puate LIII.—Fig. 1, the ovary taken from a 
flower, showing the angularly bent style. 
* Bot. Zeit. (1836) xix. 2. p. 667. 
