CHAPTER IV 







M^^^ FLORAL MECHANISMS 



'E have now come 

 to the interesting 

 group of flowers 

 which seem to 

 have invented for themselves 

 ingenious mechanisms to in- 

 sure their own cross-fer- 

 tilisation, and to prevent 

 self-fertilisation. Such a 



ferred to in the case of the 



^, v'<i mechanism has been re- 



rf- ''\_ s'fi /w^*v 1/ I'ose pogoma, as we saw on 



^ page 8, with its pollen re- 





<^^r) 





tained in a lidded box that 

 opens only as the bee makes 

 its backward exit. Practi- 

 cally all the orchids have 

 mechanisms more or less 



82 



