560     DR.  HOOKER'S  ADDRESS  TO  THE  BRITISH  ASSOCIATION. 
The  first  fruits  of  his  labors  was  his  volume  on  the  "  Fertili- 
zation of  Orchids,"  undertaken  to  show  that  the  same  plant  is 
never  continuously  fertilized  by  its  own  pollen,  and  that  there  are 
special  provisions  to  favor  the  crossing  of  individuals.  As  his 
study  of  the  British  species  advanced,  he  became  so  interested 
in  the  number,  variety,  and  complexity  of  the  contrivances  he 
met  with,  that  he  extended  his  survey  to  the  whole  family,  and 
the  result  is  a  work  of  which  it  is  not  too  much  to  say  that  it  has 
thrown  more  light  upon  the  structure  and  functions  of  the  floral 
organs  of  this  immense  and  anomalous  family  of  plants  than  had 
been  shed  by  the  labors  of  all  previous  botanical  writers.  It  has, 
further,  opened  up  entirely  new  fields  of  research,  and  discovered 
new  and  important  principles  that  apply  to  the  whole  vegetable 
kingdom. 
This  was  followed  by  his  paper  on  the  two  well-known  forms 
of  the  primrose  and  cowslip,*  popularly  known  as  the  pin-eyed 
and  the  thrum-eyed ;  these  forms  he  showed  to  be  sexual  and 
complementary  ;  their  diverse  functions  being  to  secure,  by  their 
mutual  action,  full  fertilization,  which  he  proved  could  only  take 
place  through  insect  agency.  In  this  paper  he  established  the 
existence  of  homomorphic,  or  legitimate  and  heteromorphic,  or 
illegitimate  unions  amongst  plants,  and  details  some  curious  ob- 
servations in  the  structure  of  the  pollen.  The  results  of  this, 
perhaps  more  than  any  other  of  Mr.  Darwin's  papers,  took 
botanists  by  surprise  ;  the  plants  being  so  familiar,  their  twro 
forms  of  flower  so  wTell  known  to  every  intelligent  observer,  and 
his  explanation  so  simple.  In  myself  I  felt  that  my  botanical 
knowledge  of  these  homely  plants  had  been  but  little  deeper  than 
Peter  Bell's,  to  whom 
A  primrose  by  the  river's  brim 
A  yellow  primrose  was  to  him, 
And, — it  was  nothing  more. 
Analogous  observations  on  the  dimorphism  of  flax-flowers  and 
their  allies, |  formed  the  subsequent  paper,  during  which  he  made 
the  wonderful  discovery  that  the  common  flax,  the  pollen  of  one 
form  of  flower,  is  absolutely  impotent  when  applied  to  its  own 
*  Journal  of  the  Linnean  Society,  vol.  vi,  p.  77. 
t  Journal  of  the  Linnean  Society,  vol.  vii,  p.  69. 
