﻿528 
  Nichols: 
  The 
  vegetation 
  of 
  Connecticut 
  

  

  * 
  

  

  may 
  comprise 
  an 
  important 
  element 
  in 
  the 
  flora. 
  Vaucheria 
  Thu- 
  

  

  M 
  ^ 
  

  

  form 
  

  

  m 
  

  

  expansa 
  

  

  mats 
  of 
  vegetation. 
  As 
  at 
  lower 
  levels, 
  loose 
  plants 
  of 
  Entero- 
  

  

  ■pi 
  

  

  existence. 
  

  

  maintain 
  a 
  more 
  

  

  phyllum) 
  may- 
  

  

  well 
  represented 
  in 
  the 
  upper 
  reaches 
  of 
  the 
  midlittoral 
  marsh, 
  

   either 
  by 
  loose 
  specimens 
  or 
  by 
  plants 
  that 
  have 
  become 
  partially 
  

   buried 
  in 
  the 
  mud 
  and 
  thereby 
  fixed 
  in 
  place. 
  

  

  i 
  fie 
  upper 
  Moral 
  marsh.— 
  When 
  viewed 
  from 
  a 
  distance, 
  the 
  

   meadowy 
  surf 
  ace 
  of 
  the 
  upper 
  littoral 
  marsh 
  (Figs. 
  4, 
  6, 
  9) 
  appears 
  

   to 
  be 
  flat, 
  except 
  where 
  it 
  is 
  interrupted 
  by 
  the 
  tidal 
  creeks, 
  which 
  

   commonly 
  meander 
  through 
  it, 
  or 
  by 
  tidal 
  pools 
  and 
  artificial 
  

   drainage 
  ditches. 
  But 
  the 
  ground 
  is 
  not 
  absolutely 
  flat 
  ; 
  invariably 
  

   it 
  is 
  gently 
  undulating. 
  For 
  the 
  most 
  part 
  the 
  differences 
  in 
  

   surface 
  elevation 
  are 
  very 
  slight 
  (but 
  an 
  inch 
  or 
  a 
  few 
  inches 
  at 
  

   most), 
  yet 
  they 
  are 
  sufficient 
  to 
  have 
  an 
  important 
  effect 
  on 
  the 
  

   drainage 
  and 
  wetness 
  of 
  the 
  marsh 
  surface, 
  on 
  the 
  aeration 
  and 
  

   salinity 
  of 
  the 
  substratum, 
  and 
  thereby 
  on 
  the 
  nature 
  of 
  the 
  ground 
  

   as 
  an 
  environment 
  for 
  plants.f 
  The 
  substratum 
  here 
  is 
  firm 
  and 
  

   peaty, 
  being 
  made 
  up 
  largely 
  of 
  compactly 
  interwoven 
  rhizome 
  

   and 
  root 
  remains. 
  

  

  The 
  rocfcweed 
  flora 
  of 
  salt 
  marshes 
  is 
  of 
  peculiar 
  interest 
  and 
  has 
  be^*x 
  .,.- 
  

   occasion 
  of 
  considerable 
  study. 
  Not 
  only 
  may 
  these 
  seaweeds, 
  ordinarily 
  associated 
  

   with 
  rock 
  shores, 
  form 
  an 
  essential 
  part 
  of 
  the 
  midlittoral 
  salt 
  marsh 
  vegetation, 
  but 
  

   they 
  develop 
  here 
  certain 
  remarkable 
  features 
  which 
  are 
  not 
  found 
  elsewhere. 
  In 
  

   general 
  these 
  marsh-dwelling 
  fucoids 
  are 
  characterized 
  by 
  their 
  pronounced 
  tendency 
  ■ 
  

   to 
  reproduce 
  vegetatively, 
  the 
  absence 
  of 
  sexual 
  reproduction, 
  their 
  dwarf 
  habit, 
  the 
  

   lack 
  of 
  an 
  attachment 
  disc, 
  and 
  spirality 
  or 
  curling 
  of 
  the 
  thallus- 
  For 
  detailed 
  dis- 
  

   cussion 
  and 
  references 
  to 
  the 
  literature, 
  see 
  Baker 
  and 
  Blandford 
  ('i6). 
  

  

  t 
  The 
  distribution 
  of 
  salt 
  and 
  brackish 
  marsh 
  plants 
  is 
  conditioned 
  even 
  more 
  by 
  

   the 
  salmity 
  of 
  the 
  soil 
  water 
  than 
  by 
  that 
  of 
  the 
  water 
  which 
  floods 
  the 
  surface 
  of 
  the 
  

   marsh. 
  The 
  salinity 
  of 
  the 
  soil 
  water 
  is 
  affected 
  not 
  only 
  by 
  the 
  concentration 
  of 
  the 
  

   water 
  which 
  overflows 
  the 
  surface 
  of 
  the 
  marsh 
  but 
  by 
  the 
  length 
  of 
  time 
  the 
  surface 
  

   » 
  uncovered, 
  the 
  drainage 
  relations, 
  and 
  by 
  the 
  presence 
  or 
  absence 
  of 
  subterranean 
  

   supplies 
  of 
  fresh 
  water. 
  In 
  a 
  salt 
  marsh 
  at 
  Cold 
  Spring 
  Harbor. 
  Transeau 
  ( 
  '13) 
  found 
  

   the 
  salt 
  content 
  of 
  the 
  soil 
  water 
  in 
  the 
  Sparlina 
  patens 
  association 
  to 
  be 
  but 
  75 
  Per 
  

   cent 
  as 
  great 
  as 
  that 
  of 
  the 
  harbor 
  water, 
  and 
  in 
  the 
  Juncus 
  Gerardi 
  association 
  but 
  

  

  i''- 
  T. 
  Tl; 
  ^^ 
  ^"''^^'' 
  ^^^"'^^'^"^ 
  by 
  Bartlett 
  ('09). 
  Johnson 
  and 
  York 
  ds). 
  

   Nichols 
  ( 
  18). 
  and 
  especially 
  by 
  Harshberger 
  ('ir). 
  

  

  