﻿Geographical 
  distribution 
  of 
  the 
  marine 
  spermatophytes 
  

  

  William 
  Albert 
  Setchell 
  

  

  The 
  marine 
  spermatophytes 
  belong 
  to 
  two 
  nearly 
  related 
  

   families, 
  the 
  Hydrocharltaceae 
  and 
  the 
  Potamogetonaceae. 
  

   The 
  members 
  of 
  both 
  families 
  are 
  aquatic, 
  either 
  inhabiting 
  the 
  

   fresh 
  waters 
  or 
  those 
  which 
  are 
  brackish 
  or 
  marine. 
  Of 
  the 
  first 
  

   family, 
  the 
  Hydrocharitaceae, 
  there 
  are 
  three 
  genera, 
  Halophilay 
  

   Enalus 
  and 
  Thalassia 
  which 
  are 
  marine, 
  while 
  of 
  the 
  second 
  

   family, 
  the 
  Potamogetonaceae, 
  there 
  are 
  five 
  marine 
  genera, 
  viz., 
  

   Zostera, 
  Phyllospadix, 
  Cymodocea, 
  Diplanthera 
  (or 
  Halodule) 
  and 
  

   Posidonia. 
  Of 
  these 
  eight 
  genera, 
  I 
  find 
  thirty-four 
  or 
  thirty- 
  

   five 
  species 
  at 
  present 
  enumerated. 
  Undoubtedly 
  much 
  is 
  yet 
  to 
  

  

  r 
  

  

  be 
  learned 
  concerning 
  the 
  marine 
  spermatophytes 
  since 
  they 
  

   have 
  not 
  been 
  so 
  generally 
  collected 
  and 
  studied 
  as 
  other 
  sper- 
  

   matophytes 
  because 
  of 
  their 
  habitat. 
  The 
  greater 
  number 
  of 
  the 
  

   species, 
  in 
  fact 
  all 
  except 
  the 
  three 
  species 
  of 
  Phyllospadix, 
  so 
  far 
  

   as 
  I 
  aiji 
  aware, 
  live 
  in 
  shallow 
  water 
  (down 
  to 
  not 
  over 
  lo 
  fathoms 
  

   usually) 
  and 
  are 
  seldom 
  if 
  ever 
  uncovered 
  by 
  ordinary 
  low 
  tides. 
  

   Such 
  localities 
  are 
  seldom 
  visited 
  or 
  collected 
  over 
  by 
  botanists 
  

   other 
  than 
  phycologists 
  and 
  the 
  latter 
  are 
  usually 
  in 
  search 
  of 
  

   "other 
  game.** 
  There 
  are 
  only 
  two 
  botanists 
  who 
  have 
  given 
  

   special 
  attention 
  to 
  the 
  marine 
  spermatophytes, 
  viz., 
  P. 
  Ascherson 
  

   and 
  C. 
  H. 
  Ostenfeld. 
  The 
  former 
  interested 
  all 
  explorers, 
  travel- 
  

   lers 
  and 
  navigators 
  possible 
  in 
  these 
  plants 
  and 
  obtained 
  much 
  

   that 
  was 
  valuable 
  as 
  a 
  result 
  of 
  his 
  and 
  their 
  efforts. 
  As 
  early 
  as 
  

   1867, 
  Ascherson 
  published 
  a 
  preliminary 
  account 
  of 
  the 
  marine 
  

   spermatophytes 
  as 
  then 
  known. 
  He 
  published 
  supplementary 
  

   accounts 
  In 
  1870, 
  1871 
  and 
  1875. 
  Finally 
  he 
  contributed 
  the 
  

  

  account 
  of 
  the 
  marine 
  genera 
  to 
  Engler 
  and 
  Prantl's 
  "Pflanzen- 
  

   familien" 
  (1889) 
  and 
  of 
  the 
  marine 
  species 
  of 
  the 
  Potamogetona- 
  

   ceae 
  to 
  Engler*s 
  "Pflanzenreich" 
  (1907). 
  In 
  1871, 
  Ascherson 
  

   also 
  discussed 
  the 
  geographical 
  distribution 
  of 
  the 
  "sea-grasses,'* 
  

   as 
  he 
  designated 
  the 
  marine 
  spermatophytes 
  and 
  later 
  (1906) 
  

   issued 
  a 
  revision 
  of 
  this 
  article 
  bringing 
  the 
  information 
  and 
  dis- 
  

  

  563 
  

  

  