﻿236 
  JOURNAL 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  9 
  

  

  Those 
  who 
  are 
  working 
  for 
  the 
  further 
  improvement 
  of 
  the 
  Dahlia 
  have 
  

   still 
  a 
  large 
  field 
  of 
  effort. 
  In 
  all 
  cases, 
  and 
  particularly 
  in 
  the 
  Cactus 
  types, 
  

   there 
  is 
  need 
  for 
  stronger, 
  more 
  upright 
  stems, 
  for 
  greater 
  freedom 
  of 
  flowering, 
  

   and 
  quality 
  of 
  producing 
  strong, 
  hardy 
  roots. 
  Some 
  of 
  the 
  best 
  varieties 
  are 
  

   such 
  poor 
  propagators 
  that 
  they 
  always 
  remain 
  scarce 
  and 
  expensive. 
  

  

  J. 
  B, 
  S. 
  Norton: 
  History 
  of 
  the 
  dahlia 
  varieties. 
  

  

  A 
  tabulation 
  of 
  over 
  100 
  dahlia 
  catalogues 
  of 
  1921 
  shows 
  about 
  5000 
  va- 
  

   rieties 
  now 
  on 
  the 
  market. 
  Nearly 
  5000 
  other 
  named 
  varieties 
  grown 
  in 
  

   years 
  past 
  have 
  now 
  disappeared 
  from 
  cultivation. 
  All 
  these 
  have 
  developed 
  

   in 
  the 
  gardens 
  of 
  Europe 
  and 
  America 
  since 
  the 
  wild 
  single 
  dahlia 
  was 
  in- 
  

   troduced 
  from 
  Mexico 
  into 
  European 
  gardens 
  a 
  little 
  over 
  a 
  hundred 
  years 
  ago. 
  

  

  The 
  old-fashioned 
  ball-shaped, 
  regular 
  forms, 
  or 
  show 
  dahlias, 
  were 
  the 
  

   first 
  double 
  kinds 
  developed 
  and 
  had 
  their 
  day 
  in 
  the 
  great 
  dahlia 
  shows 
  of 
  the 
  

   second 
  quarter 
  of 
  the 
  nineteenth 
  century. 
  The 
  minature 
  ball 
  forms, 
  or 
  

   pompons 
  came 
  in 
  in 
  the 
  fifties. 
  Some 
  of 
  them 
  are 
  probably 
  the 
  oldest 
  va- 
  

   rieties 
  now 
  in 
  our 
  gardens. 
  The 
  advent 
  of 
  the 
  cactus 
  dahlia 
  type 
  in 
  1873 
  

   led, 
  through 
  hybridization 
  with 
  the 
  earlier 
  kinds, 
  to 
  the 
  many 
  kinds 
  of 
  cactus, 
  

   decorative 
  and 
  peony 
  flowered 
  dahlias 
  which 
  grace 
  our 
  gardens 
  at 
  the 
  present 
  

   time. 
  The 
  show 
  dahlias, 
  so 
  desirable 
  in 
  the 
  formal 
  days 
  of 
  1830 
  to 
  1850, 
  

   have 
  now 
  almost 
  disappeared 
  from 
  prize 
  collections. 
  Even 
  the 
  graceful 
  

   cactus 
  varieties 
  which 
  were 
  the 
  fashion 
  at 
  the 
  beginning 
  of 
  the 
  twentieth 
  

   century 
  are 
  now 
  far 
  out-numbered 
  by 
  the 
  great 
  gloriously 
  colored 
  decora- 
  

   tives 
  and 
  hybrid 
  cactus 
  kinds 
  which 
  are 
  now 
  being 
  produced 
  more 
  than 
  any 
  

   other 
  types, 
  especially 
  in 
  America. 
  

  

  W. 
  E. 
  Safford: 
  Botany 
  and 
  chemistry 
  of 
  the 
  dahlia 
  (illustrated). 
  

  

  In 
  tracing 
  the 
  origin 
  of 
  the 
  cultivated 
  plants, 
  it 
  has 
  been 
  the 
  custom 
  to 
  

   go 
  back 
  to 
  the 
  very 
  earliest 
  descriptions, 
  noting 
  the 
  dates 
  when 
  they 
  were 
  writ- 
  

   ten 
  as 
  well 
  as 
  those 
  of 
  their 
  publication. 
  Among 
  early 
  writers 
  the 
  rules 
  of 
  

   nomenclature 
  now 
  followed 
  by 
  botanists 
  were 
  not 
  always 
  observed. 
  It 
  

   was 
  not 
  uncommon 
  for 
  a 
  botanist 
  to 
  ignore 
  a 
  well-established 
  generic 
  or 
  spe- 
  

   cific 
  name 
  and 
  substitute 
  another 
  more 
  in 
  accord 
  with 
  his 
  own 
  taste. 
  Thus 
  

   in 
  1809 
  Willdenow 
  attempted 
  to 
  substitute 
  Georgina 
  for 
  the 
  generic 
  name 
  

   Dahlia 
  established 
  by 
  the 
  Spanish 
  botanist 
  Cavanilles 
  in 
  1791 
  in 
  honor 
  of 
  

   Andreas 
  Dahl, 
  a 
  distinguished 
  Swedish 
  horticulturist, 
  and 
  finding 
  the 
  seed- 
  

   lings 
  of 
  the 
  type 
  of 
  the 
  genus 
  to 
  be 
  exceeding^ 
  variable, 
  he 
  also 
  changed 
  

   its 
  specific 
  name, 
  pinnata 
  to 
  variabilis. 
  The 
  variability 
  points 
  to 
  a 
  mixed 
  

   ancestry, 
  and 
  it 
  is 
  quite 
  possible 
  that 
  Cavanilles' 
  type 
  plant 
  was 
  a 
  hybrid 
  

   between 
  two 
  species 
  or 
  two 
  distinct 
  varieties 
  or 
  subspecies. 
  

  

  About 
  the 
  year 
  1576, 
  more 
  than 
  two 
  hundred 
  years 
  before 
  the 
  genus 
  Dahlia 
  

   was 
  established 
  by 
  Cavanilles, 
  Francisco 
  Hernandez, 
  a 
  Spanish 
  physician, 
  

   sent 
  by 
  Philip 
  II 
  to 
  New 
  Spain 
  to 
  study 
  its 
  resources, 
  observed 
  many 
  forms 
  of 
  

   Dahlias 
  then 
  cultivated 
  in 
  Mexico. 
  It 
  is 
  interesting 
  to 
  note 
  that 
  at 
  that 
  early 
  

   date 
  types 
  which 
  are 
  usually 
  held 
  to 
  be 
  modern 
  creations, 
  had 
  already 
  been 
  

   developed. 
  Dahlias 
  were 
  known 
  to 
  the 
  Aztecs 
  under 
  the 
  Nahuatl 
  name 
  

   Acocoxochitl, 
  which 
  may 
  be 
  translated 
  "Cane-flower." 
  This 
  name 
  was 
  

   applied 
  to 
  them 
  on 
  account 
  of 
  their 
  hollow, 
  jointed 
  stems, 
  which 
  bear 
  a 
  

   certain 
  resemblance 
  to 
  the 
  canes 
  used 
  as 
  water 
  pipes 
  or 
  tubes. 
  Hernandez 
  

   in 
  calling 
  attention 
  to 
  their 
  beautiful 
  and 
  varied 
  flowers, 
  described 
  certain 
  

   forms 
  with 
  purple 
  rays 
  and 
  yellow 
  disks, 
  and 
  many 
  others 
  differing 
  from 
  one 
  

   another 
  in 
  size 
  and 
  color; 
  some 
  white, 
  others 
  yellow, 
  others 
  red 
  or 
  purple, 
  

   or 
  white 
  tinged 
  with 
  purple, 
  or 
  perhaps 
  yellow 
  tinged 
  with 
  red, 
  and 
  a 
  great 
  

  

  