﻿THE 
  

  

  AMERICAN 
  JOURNAL 
  OF 
  SCIENCE 
  

  

  [FOURTH 
  SERIES. 
  ] 
  

  

  Art. 
  XLIII. 
  — 
  Studies 
  in 
  the 
  Cyperacece; 
  by 
  Theo. 
  Holm. 
  

   IV. 
  . 
  Didiehium 
  spathaceam 
  Pers., 
  a 
  morphological 
  and 
  

   anatomical 
  study. 
  

  

  The 
  monotypic 
  genus 
  Didiehium 
  has 
  quite 
  a 
  large 
  distribu- 
  

   tion 
  in 
  the 
  eastern 
  part 
  of 
  North 
  America, 
  extending 
  from 
  

   Nova 
  Scotia 
  as 
  far 
  south 
  as 
  to 
  the 
  tropical 
  Florida. 
  It 
  is 
  a 
  

   strictly 
  hydrophilous 
  plant, 
  growing 
  socially 
  along 
  rivers 
  or 
  on 
  

   borders 
  of 
  ponds, 
  in 
  wet 
  moss 
  or 
  in 
  the 
  water 
  itself. 
  But 
  in 
  

   spite 
  of 
  the 
  very 
  common 
  occurrence 
  of 
  our 
  plant 
  there 
  are,, 
  

   nevertheless, 
  some 
  points 
  of 
  morphological 
  and 
  anatomical 
  in- 
  

   terest, 
  which 
  have, 
  so 
  far, 
  escaped 
  the 
  attention 
  of 
  the 
  botanists. 
  

   Although 
  our 
  plant 
  possesses 
  only 
  a 
  few 
  characters, 
  by 
  which 
  it 
  

   is 
  readily 
  distinguished 
  from 
  its 
  nearest 
  allies, 
  a 
  general 
  sketch 
  

   may 
  be 
  of 
  some 
  importance 
  in 
  order 
  to 
  give 
  a 
  more 
  complete 
  

   idea 
  of 
  its 
  entire 
  organization. 
  It 
  is, 
  altogether, 
  the 
  writer's 
  

   intention 
  to 
  present 
  in 
  these 
  cyperographical 
  studies 
  a 
  number 
  

   of 
  details, 
  observed 
  in 
  the 
  various 
  representatives, 
  so 
  as 
  to 
  col- 
  

   lect 
  some 
  data, 
  which 
  might 
  facilitate 
  the 
  study 
  of 
  the 
  mutual 
  

   affinities 
  of 
  the 
  genera 
  and 
  species 
  of 
  this 
  large 
  group 
  of 
  plants. 
  

  

  In 
  regard 
  to 
  the 
  systematic 
  position 
  of 
  Dulichiiom 
  it 
  is 
  gen- 
  

   erally 
  placed 
  near 
  Cyperus 
  and 
  Kyllinga 
  on 
  account 
  of 
  the 
  

   two-ranked 
  bracts 
  of 
  the 
  inflorescence 
  ; 
  but 
  it 
  differs 
  from 
  

   these 
  genera 
  by 
  the 
  presence 
  of 
  bristles 
  in 
  the 
  flower 
  and 
  by 
  

   the 
  distinctly 
  beaked 
  achenia. 
  It 
  is, 
  also, 
  generally 
  stated 
  that 
  

   Dulichium 
  has 
  only 
  lateral 
  inflorescences 
  in 
  contrast 
  to 
  

   Cyperus 
  and 
  Kyllinga, 
  but 
  this 
  statement 
  is, 
  of 
  course, 
  not 
  

   correct, 
  as 
  shall 
  be 
  demonstrated 
  in 
  the 
  present 
  article. 
  

  

  If 
  we 
  examine 
  the 
  underground 
  part 
  of 
  Didiehium 
  we 
  

   observe 
  a 
  rather 
  long, 
  horizontal 
  rhizome 
  with 
  sympodial 
  

   ramification 
  and 
  reminding 
  one 
  very 
  much 
  of 
  Eleoeharis 
  pahes- 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Fourth 
  Series, 
  Vol. 
  Ill, 
  No. 
  18 
  — 
  June, 
  1897. 
  

   30 
  

  

  