﻿504 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  It 
  will 
  be 
  noticed 
  that 
  the 
  ratios 
  of 
  the 
  respective 
  amounts 
  of 
  growth 
  

   are 
  the 
  same 
  as 
  for 
  the 
  other 
  plants 
  tried. 
  Those 
  rooted 
  in 
  soil 
  grew 
  

   most, 
  those 
  rooted 
  in 
  sand 
  next, 
  those 
  anchored 
  over 
  sand 
  about 
  

   equally 
  with 
  those 
  suspended 
  over 
  soil, 
  and 
  both 
  less 
  than 
  those 
  rooted 
  

   in 
  sand 
  or 
  in 
  soil. 
  

  

  CERATOPHYLLIIM 
  DEMERSUM. 
  

  

  Roots 
  are 
  not 
  present 
  in 
  this 
  plant. 
  The 
  rudiment 
  of 
  a 
  root 
  exists 
  

   in 
  the 
  embr3^o, 
  but 
  does 
  not 
  develop 
  when 
  the 
  seed 
  germinates. 
  Grow- 
  

   ing 
  thus 
  without 
  roots, 
  the 
  plant 
  is 
  easily 
  carried 
  by 
  waves 
  and 
  cur- 
  

   rents 
  to 
  various 
  habitats, 
  but 
  it 
  occurs 
  most 
  abundantly 
  where 
  least 
  

   disturbed, 
  usually 
  in 
  protected 
  coves 
  where 
  the 
  water 
  is 
  a 
  meter 
  or 
  

   two 
  in 
  depth. 
  The 
  hnel}' 
  dissected 
  leaves 
  are 
  borne 
  in 
  whorls, 
  and 
  the 
  

   segments 
  are 
  rather 
  rigid, 
  so 
  that 
  a 
  plant 
  dragging 
  on 
  the 
  substratum 
  

   is 
  likely 
  to 
  become 
  anchored. 
  In 
  a 
  sheltered 
  cove 
  where 
  it 
  grows 
  

   abundantly 
  one 
  may 
  carefuU}' 
  pull 
  up 
  long 
  specimens 
  and 
  usually 
  find 
  

   that 
  a 
  portion 
  of 
  the 
  stem 
  has 
  been 
  l)uried 
  and 
  a 
  more 
  or 
  less 
  vertical 
  

   position 
  secured 
  for 
  the 
  plant. 
  Sometimes 
  the 
  central 
  portion 
  of 
  the 
  

   axis 
  is 
  buried 
  in 
  the 
  soil 
  so 
  that 
  the 
  two 
  ends 
  of 
  the 
  plant 
  are 
  free. 
  

   The 
  buried 
  portion 
  is 
  simply 
  bleached; 
  no 
  indications 
  of 
  adventitious 
  

   organs 
  can 
  be 
  noted. 
  

  

  Experiment 
  No. 
  S. 
  — 
  Aquarium 
  tests 
  were 
  made 
  with 
  this 
  plant 
  as 
  in 
  the 
  cases 
  pre- 
  

   ceding. 
  Sufficiently 
  uniform 
  figures 
  for 
  the 
  individuals 
  of 
  a 
  given 
  group 
  were 
  not 
  

   obtained. 
  Some 
  of 
  the 
  plants 
  in 
  soil 
  grew 
  more 
  than 
  some 
  of 
  those 
  in 
  sand, 
  and 
  

   conversely. 
  Likewise, 
  the 
  two 
  groups 
  of 
  anchored 
  plants 
  were 
  not 
  comparable 
  with 
  

   each 
  other, 
  nor 
  with 
  those 
  in 
  sand 
  or 
  soil. 
  In 
  view 
  of 
  such 
  results 
  and 
  the 
  fact 
  that 
  

   no 
  specialized 
  oi-gans 
  of 
  attachment 
  are 
  produced, 
  it 
  is 
  reasonable 
  to 
  consider 
  that 
  

   this 
  plant 
  is 
  not 
  directly 
  dependent 
  upon 
  the 
  soil 
  for 
  its 
  growth. 
  

  

  pota]mo(;eton 
  obtusifolius. 
  

  

  Experiment 
  No. 
  9. 
  — 
  It 
  was 
  intended 
  to 
  grow 
  this 
  plant 
  as 
  material 
  for 
  chemical 
  

   analysis, 
  cuttings 
  being 
  selected 
  from 
  fresh 
  river 
  specimens 
  and 
  jjlaced 
  in 
  floating 
  

   aquaria 
  as 
  described 
  for 
  Vallisneria 
  (experiment 
  No. 
  1, 
  p. 
  494). 
  These 
  aquaria 
  were 
  

   anchored 
  in 
  slowly 
  flowing 
  water 
  in 
  the 
  Huron 
  River, 
  Ann 
  Arbor, 
  on 
  August 
  Hand 
  

   remained 
  until 
  September 
  12. 
  By 
  the 
  latter 
  date 
  the 
  plants 
  were 
  so 
  incrusted 
  as 
  to 
  

   be 
  disqualified 
  for 
  analysis 
  and 
  only 
  the 
  general 
  result 
  may 
  be 
  recorded. 
  

  

  The 
  difference 
  in 
  favor 
  of 
  the 
  plants 
  rooted 
  in 
  soil 
  was 
  very 
  positive. 
  They 
  had 
  

   elongated 
  and 
  grown 
  considerably 
  — 
  in 
  fact, 
  behaved 
  as 
  though 
  growing 
  naturally. 
  

   The 
  suspended 
  plants 
  had 
  failed 
  to 
  grow 
  and 
  showed 
  signs 
  of 
  succumbing 
  to 
  adverse 
  

   conditions. 
  They 
  had 
  produced 
  numerous 
  unbranched 
  roots, 
  but 
  these 
  decayed 
  after 
  

   reaching 
  a 
  length 
  of 
  25 
  or 
  30 
  em. 
  No 
  rhizomes 
  were 
  produced 
  in 
  either 
  case, 
  the 
  

   new 
  growth 
  being 
  merely 
  a 
  continuation 
  of 
  branches 
  present 
  when 
  the 
  cutting 
  was 
  

   made. 
  It 
  may 
  safely 
  1)e 
  said 
  that 
  tbis 
  species 
  also 
  is 
  dependent 
  upon 
  the 
  soil 
  foi' 
  

   optimum 
  growth. 
  

  

  VALLISNERI.\ 
  AND 
  CHARA. 
  

  

  Experiment 
  No. 
  10. 
  — 
  This 
  experiment 
  was 
  conducted 
  at 
  Put-in 
  Bay, 
  Ohio, 
  during 
  

   the 
  period 
  from 
  August 
  7 
  to 
  September 
  14. 
  Having 
  observed 
  that 
  wherever 
  Vallh- 
  

   neria 
  grows 
  best 
  a 
  certain 
  type 
  of 
  soil 
  is 
  likely 
  to 
  be 
  found, 
  it 
  was 
  considered 
  desira- 
  

   ble 
  to 
  select 
  the 
  three 
  most 
  distinct 
  types 
  of 
  soil 
  occurring 
  in 
  the 
  vicinity 
  and 
  (o 
  tets 
  

  

  