﻿T. 
  Holm 
  — 
  Studies 
  in 
  the 
  Cyperacece. 
  205 
  

  

  The 
  Melananthce 
  constitute 
  a 
  very 
  interesting 
  grex 
  of 
  

   which 
  the 
  "forma 
  hebetatce" 
  resemble 
  certain 
  Vignece, 
  

   the 
  terminal 
  spike 
  being 
  gynsecandrous, 
  and 
  the 
  lateral 
  

   pistillate, 
  all 
  contiguous 
  and 
  forming 
  a 
  roundish 
  head: 
  

   G. 
  alpina 
  Sw., 
  G. 
  melanantha 
  C. 
  A. 
  Mey., 
  and 
  C. 
  mela- 
  

   nocephala 
  Turcz. 
  (C. 
  nova 
  Bail.). 
  The 
  central 
  types 
  

   begin 
  with 
  C. 
  air 
  at 
  a 
  L. 
  and 
  its 
  allies, 
  culminating 
  in 
  G. 
  

   Mertensii 
  Presc. 
  with 
  all 
  the 
  spikes 
  gyncecandrous. 
  

   Through 
  G. 
  Parryana 
  Dew. 
  with 
  the 
  terminal 
  spike 
  vary- 
  

   ing 
  from 
  gynsecandrous 
  to 
  purely 
  staminate, 
  the 
  cen- 
  

   trales 
  pass 
  into 
  C. 
  stylosa 
  C. 
  A. 
  Mey., 
  C. 
  Raynoldsii 
  Dew. 
  

   and 
  C. 
  holo 
  stoma 
  Drej. 
  with 
  the 
  terminal 
  spike 
  invari- 
  

   ably 
  staminate. 
  As 
  the 
  most 
  evolute 
  of 
  the 
  centrales 
  we 
  

   have 
  placed 
  C. 
  Buxbaumii 
  Wahlenb. 
  and 
  its 
  allies 
  ; 
  char- 
  

   acteristic 
  of 
  these 
  is 
  the 
  terminal 
  spike 
  being 
  gynsecan- 
  

   drous, 
  the 
  lateral 
  pistillate 
  and 
  more 
  or 
  less 
  remote. 
  

   Some 
  deviating 
  types 
  " 
  desciscentes" 
  we 
  have 
  placed 
  

   at 
  the 
  end 
  of 
  the 
  grex, 
  among 
  which 
  are 
  C. 
  ustulata 
  Wah- 
  

   lenb. 
  with 
  the 
  terminal 
  spike 
  occasionally 
  gynsecandrous, 
  

   C. 
  venustula 
  nob., 
  C. 
  Montanensis 
  Bail., 
  C. 
  spectabilis 
  

   Dew. 
  and 
  a 
  few 
  others, 
  of 
  which 
  the 
  perigynia 
  represent 
  

   the 
  structure 
  characteristic 
  of 
  the 
  grex. 
  

  

  While 
  thus 
  the 
  "hebetatce" 
  remind 
  of 
  the 
  Vignece, 
  

   the 
  central 
  types 
  agree 
  very 
  well 
  with 
  Carices 
  genuince, 
  

   and 
  through 
  some 
  of 
  these, 
  notably 
  C. 
  Colostoma, 
  C. 
  

   stylosa 
  and 
  C. 
  Raynoldsii, 
  the 
  grex 
  forms 
  a 
  transition 
  

   to 
  the 
  Microrhynchce; 
  through 
  C. 
  spectabilis 
  and 
  C. 
  Mon- 
  

   tanensis 
  to 
  the 
  Aeorastachyce, 
  when 
  we 
  consider 
  the 
  two 
  

   varieties, 
  described 
  in 
  the 
  preceding: 
  p 
  superba, 
  and 
  y 
  

   elegantula. 
  

  

  As 
  may 
  be 
  seen 
  from 
  the 
  preceding 
  discussion 
  of 
  these 
  

   greges, 
  Stenocarpce 
  and 
  Melananthce, 
  the 
  morphological 
  

   structure 
  of 
  the 
  shoot, 
  the 
  subterranean 
  as 
  well 
  as 
  the 
  

   aerial, 
  constitutes 
  no 
  characters 
  of 
  importance 
  for 
  the 
  

   classification 
  of 
  the 
  species 
  into 
  greges. 
  Thus 
  in 
  the 
  

   Stenocarpce 
  the 
  aphyllopodic 
  G. 
  tenuis 
  Host, 
  is 
  of 
  course, 
  

   inseparable 
  from 
  the 
  other 
  members 
  of 
  the 
  grex, 
  most 
  of 
  

   which 
  are 
  phyllopodic. 
  And 
  with 
  respect 
  to 
  the 
  Mela- 
  

   nantha 
  the 
  phyllopodic 
  C. 
  ustulata 
  Wahlenb. 
  and 
  C. 
  

   microchceta 
  nob. 
  share 
  the 
  most 
  essential 
  characters 
  with 
  

   the 
  aphyllopodic 
  C. 
  Tolmiei 
  Boott 
  and 
  C. 
  spectabilis 
  

   Dew. 
  Similar 
  cases 
  may 
  be 
  recorded 
  from 
  several 
  of 
  the 
  

   other 
  greges, 
  notably 
  the 
  Microrhynchce, 
  where 
  such 
  

   deviation 
  in 
  shoot 
  structure 
  characterizes 
  species 
  so 
  

  

  Am. 
  Jour. 
  Sci.— 
  Fourth 
  Series, 
  Vol. 
  XLIX, 
  No. 
  291.— 
  March, 
  1920. 
  

   15 
  

  

  