﻿Howe: 
  Moxosporangial 
  discs 
  in 
  Liagora 
  3 
  

  

  monosporangium-beanng 
  discs 
  look 
  at 
  hrst 
  sight 
  very 
  much 
  hke 
  

   independent 
  epi-endophytes. 
  Their 
  darker 
  red 
  color, 
  their 
  

   dorso-ventral 
  rather 
  than 
  radial 
  symmetry, 
  and 
  the 
  lack 
  of 
  any 
  

  

  i 
  

  

  obvious 
  genetic 
  continuity 
  with 
  the 
  Liagora 
  give 
  plausibility 
  to 
  

   the 
  very 
  natural 
  first 
  impression 
  that 
  they 
  are 
  independent 
  or- 
  

   ganisms 
  or 
  perhaps 
  obligate 
  epiphytes 
  of 
  various 
  species 
  of 
  the 
  

  

  r 
  

  

  genus 
  Liagora, 
  Another 
  plausible 
  a 
  priori 
  hypothesis 
  would 
  be 
  

   that 
  they 
  result 
  from 
  the 
  germination 
  of 
  carpospores 
  and 
  represent 
  

   a 
  non-sexual 
  alternating 
  phase 
  in 
  the 
  life-history 
  of 
  the 
  Liagora. 
  

   But 
  in 
  support 
  of 
  this 
  latter 
  hypothesis, 
  the 
  present 
  writer 
  finds 
  

   no 
  direct 
  evidence 
  at 
  all, 
  and 
  the 
  fact 
  that 
  in 
  L. 
  farinosa 
  these 
  

   monosporangial 
  discs 
  are 
  commonly 
  more 
  abundant 
  on 
  a'ntherldial 
  

   than 
  on 
  cystocarpic 
  plants 
  would 
  seem 
  to 
  point 
  to 
  its 
  improbability* 
  

   The 
  truth 
  seems 
  to 
  be 
  that 
  these 
  discs 
  arise 
  from 
  gonidia, 
  gemmae,, 
  

   or 
  aplanospores, 
  derived 
  from 
  the 
  terminal 
  or 
  subterminal 
  cells 
  of 
  

   the 
  assimilatory 
  filaments 
  of 
  the 
  Liagora, 
  as 
  was 
  the 
  view 
  of 
  

   Kiitzing 
  in 
  regard 
  to 
  similar 
  structures 
  in 
  Liagora 
  Turneri. 
  Kiitz- 
  

   ing 
  appears 
  to 
  be 
  the 
  only 
  one 
  who 
  has 
  previously 
  alluded 
  to 
  

   these 
  structures 
  in 
  print 
  and 
  his 
  observations 
  appear 
  to 
  have 
  been 
  

  

  r 
  

  

  overlooked 
  or 
  ignored 
  by 
  subsequent 
  writers 
  on 
  the 
  genus. 
  These 
  

   monosporangial 
  discs 
  are 
  especially 
  common 
  iri 
  West 
  Indian 
  

  

  on 
  both 
  

  

  specimens 
  of 
  Liagora 
  ceranoides 
  Lamour. 
  {L. 
  pulveruh 
  

   and 
  L. 
  farinosa 
  Lamour. 
  (L. 
  elongata 
  Zan.), 
  occurring 
  

   antheridial 
  and 
  cystocarpic 
  plants. 
  In 
  L, 
  ceranoides, 
  the 
  gemmae 
  

   are 
  unicellular 
  or 
  bicellular, 
  terminal 
  or 
  subterminal, 
  solitary' 
  or 
  

   concatenate, 
  but 
  are 
  most 
  frequently 
  derived 
  from 
  the 
  terminal 
  

   (distal) 
  cells 
  of 
  the 
  assimilatorj^ 
  filaments. 
  The 
  cell 
  enlarges, 
  its 
  

   contents 
  become 
  deeper 
  red, 
  its 
  walls 
  become 
  soft 
  and 
  mucous, 
  

   and 
  a 
  new 
  cell 
  wall 
  is 
  laid 
  down 
  inside 
  the 
  old 
  one 
  (Figs, 
  i 
  and 
  2). 
  

   Sometimes 
  the 
  rejuvenated 
  cell 
  or 
  aplanospore 
  escapes 
  from 
  the 
  

   old 
  wall 
  before 
  germinating, 
  but 
  nearly 
  always 
  in 
  this 
  species, 
  as 
  

   in 
  i, 
  valida 
  Harv., 
  germination 
  takes 
  place, 
  or 
  at 
  least 
  begins, 
  

   in 
  situ. 
  The 
  original 
  wall, 
  however, 
  becomes 
  so 
  tenuous 
  that 
  the 
  

   aplanospore 
  or 
  young 
  disc 
  is 
  very 
  easily 
  detached 
  from 
  Its 
  place 
  

   of 
  origin 
  and 
  even 
  when 
  it 
  develops 
  in 
  its 
  original 
  position, 
  the 
  

   original 
  walls 
  dissolve 
  so 
  completely 
  that 
  It 
  is 
  usually 
  very 
  difficult 
  

   to 
  assure 
  one's 
  self 
  of 
  its 
  genetic 
  connection 
  with 
  the 
  filament 
  from 
  

   which 
  it 
  was 
  derived. 
  Occasionally, 
  the 
  cell, 
  with 
  Its 
  original 
  

  

  