﻿T 
  Holm 
  — 
  Pogonia 
  ophioglossoides. 
  13 
  

  

  Art. 
  III. 
  — 
  Pogonia 
  ophioglossoides 
  Nutt. 
  A. 
  morpholog- 
  

   ical 
  and 
  anatomical 
  study 
  • 
  by 
  Theo. 
  Holm. 
  (With 
  four 
  

   figures.) 
  

  

  The 
  genus 
  Pogonia 
  is 
  represented 
  in 
  the 
  Atlantic 
  States 
  by 
  

   five 
  species, 
  which 
  according 
  to 
  Bentham 
  and 
  Hooker 
  are 
  to 
  

   be 
  classified 
  in 
  no 
  less 
  than 
  three 
  sections, 
  viz 
  : 
  Eupogonia 
  

   [P. 
  ophioglossoides 
  Nutt. 
  and 
  P. 
  divaricata 
  R. 
  Br.), 
  Triphora 
  

   (P. 
  pendula 
  Lindl.) 
  and 
  Codonorchis 
  {P. 
  verticillata 
  Nutt. 
  

   and 
  P. 
  aifinis 
  Anst.). 
  It 
  deserves 
  notice 
  that 
  these 
  sections 
  

   are 
  established 
  rather 
  upon 
  the 
  vegetative 
  than 
  upon 
  the 
  floral 
  

   characters, 
  and 
  Bentham 
  and 
  Hooker 
  have 
  pointed 
  out, 
  that 
  

   the 
  stem 
  has 
  but 
  one 
  leaf, 
  one 
  bract 
  and 
  one 
  flower 
  in 
  Eupo- 
  

   gonia, 
  while 
  in 
  Triphora 
  there 
  are 
  several 
  leaves, 
  bracts 
  and 
  

   flowers 
  : 
  finally 
  in 
  Codonorchis 
  the 
  stem 
  bears 
  a 
  whorl 
  of 
  three 
  

   to 
  six 
  leaves 
  and 
  a 
  single 
  flower 
  or 
  seldom 
  two 
  as 
  in 
  P. 
  ajjinis. 
  

   Besides 
  these 
  vegetative 
  characters 
  the 
  floral 
  ones 
  offer 
  several 
  

   important 
  points 
  useful 
  to 
  the 
  classification 
  of 
  these 
  singular 
  

   plants, 
  thus 
  Xuttall 
  and 
  Rafinesque 
  separated 
  their 
  genera 
  

   Triphora 
  (Nutt.), 
  Isotria 
  and 
  Odonectis 
  (Raf.) 
  from 
  Pogonia 
  

   proper, 
  the 
  two 
  last 
  being, 
  however, 
  identical 
  with 
  Codonorchis 
  

   Lindl. 
  It 
  must 
  be 
  admitted 
  that 
  the 
  general 
  habit 
  of 
  these 
  

   plants 
  is 
  very 
  different, 
  and 
  even 
  if 
  no 
  further 
  distinctions 
  were 
  

   to 
  be 
  drawn 
  than 
  those 
  recorded 
  by 
  Bentham 
  and 
  Hooker, 
  it 
  

   would 
  seem 
  very 
  natural 
  to 
  consider 
  these 
  species 
  as 
  represent- 
  

   ing 
  three 
  well 
  defined 
  genera. 
  However 
  if 
  we 
  examine 
  the 
  

   parts 
  underground, 
  we 
  find 
  a 
  few 
  additional 
  characters, 
  which 
  

   are 
  no 
  less 
  important 
  to 
  the 
  classification 
  of 
  the 
  species. 
  

  

  The 
  roots 
  are 
  generally 
  described 
  as 
  " 
  thick 
  fibers," 
  "a 
  cluster 
  

   of 
  fibers" 
  or 
  " 
  oblong 
  tubers" 
  and 
  Willdenow 
  described 
  his 
  

   Aretkusa 
  pendula 
  as 
  possessing 
  a 
  tuberous 
  root; 
  this 
  plant 
  is 
  

   Nuttall's 
  Triphora 
  pendula, 
  and 
  it 
  is, 
  also, 
  the 
  " 
  Helleborine 
  

   mariana, 
  fiore 
  pendulo 
  purpureo 
  trianthophoros" 
  of 
  Plukenet. 
  

   But 
  otherwise 
  the 
  systematic 
  authors 
  give 
  no 
  further 
  details 
  in 
  

   regard 
  to 
  the 
  root-svstem 
  and 
  no 
  information 
  whatever 
  con- 
  

   cerning 
  the 
  rhizome. 
  Oar 
  species 
  of 
  Pogonia 
  are 
  all 
  terres- 
  

   trial 
  and. 
  excepting 
  P. 
  pendula, 
  possess 
  a 
  slender 
  rhizome, 
  

   which 
  is 
  relatively 
  short, 
  vertical 
  or 
  ascending 
  and 
  densely 
  cov- 
  

   ered 
  with 
  long, 
  unicellular 
  hairs. 
  Underground 
  stems 
  with 
  

   hairs 
  are 
  rare, 
  but 
  are 
  known 
  in 
  other 
  genera 
  of 
  the 
  Orchidew, 
  

   for 
  instance 
  Listera, 
  Goodyera 
  and 
  the 
  rootless 
  Corallorhiza. 
  

   In 
  examining 
  a 
  rhizome 
  of 
  Pogonia 
  ophioglossoides 
  (fig. 
  3) 
  we 
  

   find 
  it 
  consists 
  of 
  five 
  distinct 
  internodes 
  ( 
  i 
  1 
  - 
  i 
  5 
  ), 
  the 
  uppermost 
  

   passing 
  into 
  a 
  flower-bearing 
  stem 
  (St.). 
  The 
  rhizome 
  is 
  

   vertical, 
  bearing 
  rudiments 
  of 
  two 
  green 
  leaves 
  (L'-L 
  2 
  ) 
  and 
  

   two 
  scale-like 
  and 
  membranaceous 
  {VT), 
  while 
  a 
  third 
  scale-like 
  

   one 
  is 
  still 
  fresh 
  and 
  surrounds 
  the 
  base 
  of 
  the 
  flower-bearing 
  

  

  