﻿Nichols: 
  The 
  vegetation 
  of 
  Connecticut 
  525 
  

  

  below, 
  on 
  which 
  the 
  aquatic 
  eel 
  grass 
  :s 
  the 
  character 
  plant, 
  and 
  

   the 
  salt 
  marshes 
  above, 
  in 
  which 
  terrestrial 
  grasses 
  are 
  the 
  pre- 
  

   dominant 
  forms- 
  At 
  ordinary 
  low 
  tides 
  these 
  tidal 
  flats 
  of 
  the 
  

   lower 
  littoral 
  present 
  a 
  surface 
  of 
  soft, 
  blue-black, 
  ill-smelling 
  

   mud 
  — 
  an 
  area 
  in 
  which, 
  except 
  for 
  local 
  colonies 
  of 
  eel 
  grass 
  or 
  

   salt 
  marsh 
  grass 
  {Spartina 
  glabra) 
  , 
  seed 
  plants 
  and 
  attached 
  algae 
  

   are 
  practically 
  absent. 
  At 
  certain 
  seasons 
  these 
  muddy 
  flats 
  

   may 
  be 
  destitute 
  of 
  visible 
  vegetation 
  of 
  any 
  description; 
  but 
  at 
  

   others 
  the 
  bare 
  mud 
  at 
  low 
  tide 
  is 
  littered 
  with 
  loose 
  sheets 
  of 
  

   Ulva 
  and 
  tangles 
  of 
  Enter 
  omorpha, 
  which 
  may 
  cover 
  the 
  ground 
  so 
  

   thickly 
  that, 
  when 
  viewed 
  from 
  a 
  distance, 
  the 
  surface 
  appears 
  

   verdant 
  green. 
  The 
  failure 
  of 
  the 
  eel 
  grass 
  to 
  flourish 
  on 
  tidal 
  

   flats 
  is 
  probably 
  associated 
  with 
  its 
  inability 
  to 
  withstand 
  the 
  

   desiccation 
  and 
  extreme 
  temperatures 
  to 
  which 
  plants 
  growing 
  

   here 
  are 
  frequently 
  subjected 
  at 
  low 
  tide. 
  The 
  influence 
  of 
  these 
  

   factors 
  must 
  also 
  react 
  unfavorably 
  on 
  Ulva 
  and 
  Enteromorpha, 
  

   but 
  the 
  loose 
  carpet 
  of 
  vegetation 
  which 
  these 
  form 
  is 
  constantly 
  

   being 
  renewed 
  by 
  fresh 
  plants 
  washed 
  in 
  by 
  the 
  tides 
  and 
  currents. 
  

   The 
  inability 
  of 
  the 
  salt 
  marsh 
  grass, 
  character 
  plant 
  of 
  the 
  next 
  

   higher 
  zone, 
  to 
  colonize 
  the 
  flats, 
  is 
  probably 
  due 
  to 
  the 
  inadequate 
  

   aeration, 
  particularly 
  of 
  its 
  subterranean 
  organs, 
  at 
  these 
  lower 
  

   levels 
  (see 
  detailed 
  discussion 
  in 
  Johnson 
  and 
  York, 
  '15). 
  

  

  The 
  midlittoral 
  mursh. 
  —Salt 
  marshes 
  are 
  typically 
  developed 
  

   on 
  muddy 
  bottoms, 
  between 
  approximately 
  mean 
  half 
  and 
  high 
  

   tide 
  levels, 
  and 
  their 
  vegetation, 
  taken 
  in 
  its 
  entirety, 
  is 
  charac- 
  

   terized 
  by 
  the 
  predominance 
  of 
  perennial 
  grasses 
  or 
  grass-like 
  

   plants. 
  The 
  nature 
  of 
  the 
  plant 
  cover 
  exhibits 
  certain 
  striking 
  

   differences, 
  however, 
  primarily 
  in 
  relation 
  to 
  tide 
  levels 
  (Fig. 
  4)- 
  

   At 
  the 
  lower 
  levels, 
  in 
  the 
  region 
  of 
  greatest 
  tidal 
  play, 
  the 
  vege- 
  

   tation 
  is 
  made 
  up 
  largely 
  of 
  coarse, 
  reedy 
  grasses, 
  between 
  three 
  

   and 
  five 
  feet 
  tall 
  ; 
  at 
  the 
  higher 
  levels 
  it 
  consists 
  mainly 
  of 
  finer, 
  

   lower 
  grasses 
  and 
  grass-like 
  plants, 
  mostly 
  under 
  a 
  foot 
  in 
  height. 
  

   The 
  area 
  occupied 
  by 
  the 
  reedy 
  grasses, 
  extending 
  from 
  the 
  lower 
  

   limits 
  of 
  the 
  marsh 
  upward 
  to 
  within 
  a 
  few 
  inches 
  of 
  the 
  level 
  

   reached 
  by 
  ordinary 
  high 
  tides 
  (approximately 
  to 
  neap 
  high 
  tide 
  

   level) 
  , 
  may 
  be 
  designated 
  the 
  midlittoral 
  or 
  reed 
  marsh 
  ; 
  while 
  the 
  

   area 
  occupied 
  by 
  the 
  finer 
  grasses, 
  comprising 
  the 
  higher 
  surface 
  of 
  

   the 
  marsh, 
  may 
  be 
  termed 
  the 
  upper 
  littoral 
  marsh 
  or 
  meadow. 
  

  

  