﻿126 
  T. 
  Holm 
  — 
  Studies 
  in 
  the 
  Cyperacece. 
  

  

  coating 
  of 
  the 
  pericarp 
  (fig. 
  9). 
  The 
  stem 
  above-ground, 
  which 
  

   at 
  its 
  apex 
  bears 
  the 
  inflorescence, 
  is 
  in 
  our 
  plant 
  flattened 
  

   almost 
  in 
  its 
  entire 
  length, 
  except 
  at 
  the 
  base, 
  where 
  it 
  is 
  

   strictly 
  cylindric. 
  The 
  anatomical 
  structure 
  is, 
  however, 
  the 
  

   same 
  whether 
  we 
  examine 
  the 
  cylindric 
  or 
  the 
  flattened 
  part, 
  

   except 
  in 
  regard 
  to 
  the 
  pith, 
  which 
  is 
  broken 
  in 
  the 
  upper 
  

   part 
  of 
  the 
  stem, 
  rendering 
  this 
  hollow 
  ; 
  this 
  character, 
  the 
  

   hollow 
  stem, 
  is 
  rather 
  uncommon 
  in 
  the 
  Carices, 
  although 
  it 
  has 
  

   been 
  observed 
  in 
  certain 
  species. 
  The 
  epidermis 
  of 
  the 
  stem 
  

   is 
  very 
  uniform 
  and 
  thin-walled 
  ; 
  it 
  possesses 
  the 
  interior 
  

   silicious 
  cones, 
  but 
  is 
  like 
  the 
  epidermis 
  of 
  the 
  leaf, 
  entirely 
  

   destitute 
  of 
  exterior 
  expansions. 
  The 
  bark-parenchyma 
  is 
  

   quite 
  large 
  and 
  consists 
  of 
  very 
  thin-walled 
  roundish 
  cells, 
  

   which 
  gradually 
  pass 
  over 
  into 
  a 
  large 
  tissue 
  of 
  polygonal 
  cells, 
  

   which 
  occupy 
  the 
  greater 
  inner-part 
  of 
  the 
  stem 
  and 
  which 
  

   represents 
  a 
  typical 
  pith'. 
  

  

  Mestome-bundles 
  are 
  quite 
  numerous 
  and 
  form 
  two 
  concen- 
  

   tric 
  rows, 
  viz 
  : 
  an 
  outer 
  row 
  of 
  large 
  bundles, 
  supported 
  by 
  

   heavy 
  layers 
  of 
  stereome, 
  especially 
  on 
  the 
  outer 
  side 
  and 
  bor- 
  

   dering 
  immediately 
  on 
  the 
  epidermis, 
  while 
  the 
  inner 
  row 
  of 
  

   mestome-bundles 
  is 
  only 
  supported 
  by 
  a 
  very 
  small 
  layer 
  of 
  

   stereome. 
  The 
  bundles 
  of 
  the 
  inner 
  row 
  are 
  smaller 
  and 
  

   are 
  imbedded 
  in 
  the 
  bark 
  in 
  alternation 
  with 
  the 
  mestome- 
  

   bundles 
  of 
  the 
  outer 
  row. 
  Concerning 
  the 
  structure 
  of 
  these 
  

   bundles, 
  the 
  larger 
  ones 
  are 
  exactly 
  built 
  up 
  as 
  those 
  of 
  the 
  

   leaf, 
  except, 
  of 
  course, 
  that 
  no 
  mestome-sheath 
  is 
  developed, 
  

   this 
  being 
  always 
  confined 
  to 
  the 
  leaf-bundles. 
  

  

  The 
  rhizome 
  of 
  our 
  plant 
  is 
  very 
  short 
  on 
  account 
  of 
  its 
  

   cespitose 
  growth, 
  and 
  the 
  ascending 
  shoots 
  do 
  not 
  push 
  out 
  in 
  

   any 
  considerable 
  distance 
  from 
  the 
  main 
  rhizome. 
  The 
  interior 
  

   structure 
  corresponds 
  in 
  most 
  respects 
  with 
  that 
  of 
  the 
  stem 
  

   above 
  ground, 
  viz 
  : 
  the 
  development 
  of 
  the 
  bark, 
  the 
  arrange- 
  

   ment 
  of 
  the 
  mestome-bundles 
  in 
  two 
  concentric, 
  alternating 
  

   rows, 
  and 
  finally 
  by 
  the 
  central 
  pith. 
  We 
  notice, 
  however, 
  

   some 
  characters 
  in 
  the 
  rhizome 
  by 
  which 
  this 
  differs 
  from 
  the 
  

   stem 
  above 
  ground, 
  viz 
  : 
  the 
  presence 
  of 
  an 
  endodermis, 
  sur- 
  

   rounding 
  the 
  bundles, 
  thus 
  separating 
  them 
  from 
  the 
  proper 
  

   bark-parenchyma. 
  The 
  bark 
  itself 
  is 
  in 
  the 
  rhizome 
  composed 
  

   of 
  rather 
  thick-walled 
  cells, 
  all 
  of 
  which 
  contain 
  deposits 
  of 
  

   starch 
  ; 
  the 
  endodermis 
  consists 
  of 
  roundish 
  cells, 
  which 
  are 
  

   thickened 
  all 
  around. 
  As 
  regards 
  the 
  mestome-bundles 
  these 
  

   are 
  more 
  or 
  less 
  surrounded 
  by 
  stereome, 
  the 
  cells 
  of 
  which 
  

   are 
  not 
  very 
  thick-walled. 
  We 
  notice 
  here, 
  as 
  in 
  the 
  stem, 
  

   that 
  the 
  two 
  rows 
  of 
  bundles 
  show 
  a 
  different 
  development 
  in 
  

   regard 
  to 
  their 
  relative 
  size, 
  besides 
  that 
  the 
  larger 
  are 
  here 
  

   perihadrornatic, 
  i. 
  e. 
  the 
  leptome 
  is 
  central 
  and 
  surrounded 
  by 
  

   the 
  elements 
  of 
  the 
  hadrome. 
  The 
  central 
  part 
  of 
  the 
  rhizome 
  

   is 
  occupied 
  by 
  a 
  thick-walled 
  pith, 
  the 
  cells 
  of 
  which 
  contain 
  

  

  