Am.  Jour.  Pharm.  ) 
March  1, 1872.  / 
The  Odors  of  Plants. 
123 
Roses  and  pinks  occur  to  one  at  once,  when  sweet-scented  red- 
flowered  plants  are  referred  to ;  but  with  these  exceptions  it  is  diffi- 
cult to  characterize  the  odors  of  plants  belonging  to  this  series.  But 
among  lilac  flowers  a  great  resemblance  in  scent  mavbe  traced;  thus 
the  sweet  odor  of  vanilla,  which  is  so  powerful  in  the  garden  helio- 
trope, is  found  again  in  different  degrees  of  intensity  in  Petasites 
fragrans,  Valeriana  officinalis,  and  the  common  lilac  ;  we  meet  with 
it  also  in  Plantago  media,  which  is  exceptional  among  plantains  in  its 
fragrance  and  in  its  colored  corolla. 
Blue  flowers  are  very  rarely  fragrant,  and  when  so,  only  in  a  slight 
degree.  The  blue  variety  of  Phyteuma  spicata  exhales  a  faint  per- 
fume, and  one  or  two  campanulas  are  slightly  scented.  Franeiscea 
Hopeana  has,  however,  deliciously  fragrant  blossoms,  which  recall  at 
once  the  scent  of  the  orange  and  the  tuberose  ;  but  although  at  first 
blue,  they  soon  lose  their  color  and  become  white. 
Certain  species,  the  flowers  of  which  arc  of  sombre  hues,  are  very 
fragrant.  Thus  in  the  early  flowering  Galycanthus  prcecox,  one  finds 
a  multitude  of  odors,  such  as  rose,  jasmine  and  tuberose,  harmoni- 
ously blended.  The  night-flowering  stock  [Matthiola  tristis),  Ilesperis 
tristis,  and  one  or  two  more,  compensate  by  their  fragrance  for  the 
absence  of  beauty  of  color  ;  while  other  dark-flowered  plants,  such  as 
the  henbane,  have  an  intensely  disagreeable  odor. 
Thus  we  see  that  it  is  not  the  most  brilliant  flowers  which  are  the 
most  fragrant ;  indeed,  many  of  the  most  brilliant  in  color  ha  ve  no 
scent  whatever.  The  beautiful  Malvaceae  of  equinoctial  America,  the 
pelargoniums  of  the  Cape,  the  passion-flowers  (?),  the  gladioli,  and 
some  of  the  most  striking  Leguminosce  are  destitute  of  perfume. 
One  or  two  conclusions  as  to  the  geographical  distribution  of  sweet- 
scented  plants  may  be  arrived  at  from  the  preceding  facts,  united  with 
many  more  which  space  will  not  permit  us  to  cite.  We  have  seen 
that  a  large  proportion  of  pale  and  white  blossoms  are  fragrant ;  and 
it  is  ascertained  that  these  predominate  in  northern  regions.  We  may 
therefore  conclude  that  the  relative  number  of  odorous  flowers  is 
greater  towards  the  poles  than  towards  the  equator.  It  would  seem 
that  the  too  powerful  action  of  light  and  heat  is  opposed  to  the  ema- 
nation of  the  odors  of  flowers  ;  and  we  see  many  species,  which  are 
scarcely  fragrant  during  the  day,  become  so  in  the  evening  or  at  night. 
But  if  the  odors  emitted  by  the  blossoms  are  more  frequent  in  the 
North,  the  reverse  is  the  case  with  the  essences  enclosed  in  the  glands. 
