﻿T. 
  Holm 
  — 
  Studies 
  in 
  the 
  Cyperacece. 
  359 
  

  

  Habitat 
  : 
  Near 
  Denver, 
  Colorado 
  (E. 
  L. 
  Greene). 
  Common 
  

   on 
  dry 
  rocks 
  in 
  the 
  Aspen-zone 
  at 
  Long's 
  Peak, 
  middle 
  Colo- 
  

   rado, 
  at 
  8,600 
  feet 
  (the 
  author). 
  

  

  Differs 
  from 
  G 
  filifolia 
  by 
  its 
  broader 
  leaves, 
  and 
  more 
  

   robust 
  culm, 
  but 
  especially 
  by 
  the 
  pointed 
  scales 
  and 
  the 
  pubes- 
  

   cence 
  of 
  the 
  utricle. 
  

  

  These 
  morphological 
  characters 
  may 
  be 
  supplemented 
  by 
  

   some 
  others, 
  derived 
  from 
  the 
  internal 
  structure 
  of 
  these 
  

   species 
  together 
  with 
  G. 
  filifolia 
  Nutt., 
  in 
  order 
  to 
  draw 
  the 
  

   specific 
  distinction 
  still 
  more 
  completely. 
  The 
  anatomical 
  

   structure 
  is 
  as 
  follows 
  : 
  

  

  The 
  root. 
  

  

  Inside 
  the 
  epidermis, 
  which, 
  shows 
  the 
  usual 
  structure, 
  is 
  a 
  

   hypoderm 
  of 
  a 
  single 
  stratum 
  large, 
  thin-walled 
  cells 
  in 
  G. 
  

   filifolia, 
  or 
  of 
  thick-walled 
  in 
  G 
  oreocharis, 
  or 
  finally 
  of 
  three 
  

   to 
  four 
  thin- 
  walled 
  strata 
  in 
  G 
  elynoides. 
  The 
  cortex 
  is 
  devel- 
  

   oped 
  as 
  two 
  very 
  distinct 
  zones, 
  of 
  which 
  the 
  outer 
  consists 
  of 
  

   stereids, 
  the 
  inner 
  one, 
  on 
  the 
  contrary, 
  of 
  mostly 
  thin-walled 
  

   parenchyma, 
  which 
  shows 
  the 
  characteristic 
  tangential 
  collaps- 
  

   ing, 
  excepting 
  the 
  innermost 
  stratum, 
  which 
  borders 
  on 
  endo- 
  

   dermis. 
  The 
  thickness 
  of 
  these 
  two 
  layers 
  seems 
  to 
  vary 
  in 
  

   these 
  species, 
  and 
  we 
  notice 
  for 
  instance 
  in 
  G. 
  filifolia 
  that 
  the 
  

   stereomatic 
  portion 
  consists 
  of 
  nine 
  strata, 
  while 
  there 
  are 
  only 
  

   four 
  in 
  the 
  two 
  other 
  species. 
  Moreover, 
  in 
  G 
  filifolia 
  the 
  

   outer 
  cortex 
  is 
  interspersed 
  with 
  rays 
  of 
  thin-walled 
  paren- 
  

   chyma, 
  which 
  do 
  not 
  show 
  any 
  signs 
  of 
  collapsing. 
  The 
  inner 
  

   cortex 
  is 
  thin-walled 
  throughout 
  in 
  G 
  elynoides 
  and 
  G 
  filifolia, 
  

   but 
  in 
  G 
  oreocharis 
  only 
  the 
  five 
  or 
  six 
  inner 
  strata 
  are 
  thin- 
  

   walled, 
  the 
  outermost 
  four 
  or 
  five 
  being 
  distinctly 
  thickened, 
  

   but 
  not, 
  however, 
  to 
  such 
  an 
  extent 
  as 
  the 
  stereomatic 
  part 
  of 
  

   the 
  cortex. 
  The 
  endodermis 
  is 
  thick-walled 
  in 
  Garex 
  filifolia 
  

   and 
  G. 
  elynoides, 
  but 
  not 
  so 
  in 
  G 
  oreocharis. 
  By 
  examining 
  

   the 
  pericambium 
  we 
  find 
  this 
  as 
  only 
  one 
  stratum 
  in 
  all 
  three 
  

   species, 
  thin- 
  walled 
  in 
  G. 
  elynoides 
  and 
  G. 
  filifolia, 
  but 
  thick- 
  

   ened 
  in 
  G. 
  oreocharis. 
  This 
  tissue, 
  the 
  pericambium, 
  is 
  in 
  G. 
  

   el 
  'ijnoides 
  interrupted 
  by 
  all 
  the 
  proto-hadrome 
  vessels, 
  but 
  not 
  

   so 
  in 
  the 
  two 
  other 
  species 
  ; 
  in 
  one 
  root 
  of 
  G 
  filifolia, 
  for 
  

   instance, 
  six 
  proto-hadrome 
  vessels 
  out 
  of 
  twenty-one 
  had 
  not 
  

   broken 
  through 
  the 
  pericambium, 
  while 
  in 
  some 
  thinner 
  roots 
  

   only 
  one 
  of 
  these 
  vessels 
  out 
  of 
  sixteen 
  bordered 
  on 
  endodermis. 
  

   The 
  leptome 
  and 
  the 
  proto-leptome 
  is 
  very 
  well 
  developed 
  in 
  

   these 
  species 
  and 
  arranged 
  in 
  alternation 
  with 
  the 
  proto- 
  

   hadrome. 
  Some 
  large 
  vessels 
  surround 
  the 
  innermost 
  part 
  of 
  

   the 
  central-cylinder, 
  which 
  is 
  occupied 
  by 
  conjunctive 
  tissue, 
  

   especially 
  thick-walled 
  in 
  G 
  elynoides 
  and 
  G. 
  filifolia. 
  In 
  

   passing 
  to 
  examine 
  

  

  