\m.  Jour.  Pharm. 
December,  1914. 
Belladonna  and  Hyoscyamus. 
54i 
Pollination  in  Hyoscyamus  plants  not  under  experimental  control 
takes  place  partly  by  means  of  insects  carrying  pollen  from  the 
flowers  of  one  lot  of  plants  to  the  flowers  of  other  plants  which  may 
be  of  a  different  variety  or  form.  This  gives  rise  to  vicinists,  and 
hence  seed  supplies  from  field-grown  or  wild  plants  collected  where 
several  forms  are  growing  together  will  not  infrequently  produce 
hybrids  rather  than  pure  species  or  varieties.  And  for  the  same 
reason  commercial  seed  supplies,  unless  obtained  from  plants  grown 
under  control  or  from  plants  grown  in  isolated  districts,  will  not 
Fig.  5. — Flowers  of  Hyoscyamus  albus. 
always  yield  pure  races.  Furthermore,  it  should  be  pointed  out  that 
H.  albus  is  probably  not  an  elementary  species,  but  rather  a  retro- 
grade variety  of  //.  niger,  in  which  the  unit  character  anthocyanin 
is  more  or  less  latent.  This  difference  between  elementary  species 
and  certain  systematic  species  has  been  fully  discussed  by  De  Vries, 
and  the  importance  of  a  physiological  classification  based  upon 
physiological  units  should  not  be  underestimated  by  those  engaged 
in  medicinal  plant  breeding.  To  illustrate  the  difference  between  an 
elementary  species  and  a  systematic  species  or  variety,  De  Vries 
