Am.  Jour.  Pharm.  \ 
April,  1904.  / 
The  Genus  Eucalyptus. 
179 
comprehensive  view  of  the  subject,  and  are  less  likely  to  err  in  their 
conclusions,  as  experience  covering  many  years  has  shown  them 
that  a  species  founded  on  field  studies,  the  usual  morphological 
data,  as  well  as  structure  and  nature  of  cell  contents,  is  practically 
constant  in  specific  characters.  This  is  in  a  certain  sense  the  most 
interesting  part  of  their  work.  It  is  not  at  all  unlikely  that  the  next 
important  classification  of  plants  will  be  based  largely  on  such  his- 
tological and  physiological  data  as  Baker  and  Smith  have  consid- 
ered in  their  studies  on  this  single  genus.  Engler  and  Prantl  have 
attempted  to  utilize  in  a  measure  this  kind  of  information  on  the  entire 
plant  kingdom,  but  it  has  been  unsatisfactory,  because  the  work  done 
is  not  sufficient  and  in  most  cases  still  requires  confirmation.  Baker 
and  Smith  have  made  an  excellent  beginning,  and  have  set  the  pace 
for  all  writers  of  monographs  on  other  plant  genera. 
Baker  and  Smith  have  divided  the  eucalypts  into  the  following 
groups,  based  on  the  character  of  the  oils  they  yield : 
Group  I. — Eucalypts  which  give  an  oil  consisting  largely  of 
pinene,  without  phellandrene,  and  in  which  eucalyptol  is  almost 
or  quite  absent :  Eucalyptus  tesselaris,  E.  trachyphloia\  E.  terminalis, 
E.  corymbosa,  E.  intermedia,  E.  eximia,  E.  botryoides,  E.  robusta,  E. 
saligna,  E.  nova-anglica,  E.  umbra,  E.  dextropinea,  E.  Wilkinsoniana 
and  E.  Icevopinea. 
Group  II. — Eucalypts  which  yield  an  oil  consisting  principally 
of  pinene  and  eucalyptol,  but  in  which  the  latter  constituent  does 
not  exceed  40  per  cent.,  phellandrene  being  absent :  Eucalyptus 
Baeuerleni,  E.  propinqua,  E.  affinis,  E.  paludosa,  E.  /actea,  E.  rubida, 
E.  inter texta,  E.  maculata,  E.  microcorys,  E.  hemilanipra,  E.  quadran- 
gidata,  E.  conica,  E.  Bosistoana,  E.  eugenioides  and  E.  paniculata. 
Group  III,  Class  A. — Eucalypts  which  yield  an  oil  consisting 
principally  of  eucalyptol  and  pinene,  and  in  which  the  eucalyptol 
exceeds  40  per  cent.,  phellandrene  being  absent :  Eucalyptus  resini. 
fera,  E.  polyanthema,  E.  Behriana,  E.  Rossii,  E.  pendula,  E.  dealbata, 
E.  tereticornis  var.  linearis,  E.  rostrata  var.  botealis,  E.  maculosa,  E. 
camphora,  E.  punctata,  E.  squamosa,  E.  Bridgesiana,  E.  goniocalyx, 
E.  bicolor,  E.  viminalis  var.  (a),  E.  populifolia,  E.  longifolia,  E.  iVJaideni, 
E.  globulus,  E.  pulverulenta,  E.  cinerea,  E.  Stuartiana,  E.  Stuartiana 
var.  cordata,  E.  Morrisii,  E.  Smithii  and  E.  sideroxylon. 
Group  III,  Class  B. — Eucalypts  which  yield  an  oil  containing 
over  40  per  cent,  of  eucalyptol,  but  in  which  the  pinene  is  dimin 
