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  Apogamy 
  in 
  Osmunda 
  345 
  

  

  4 
  

  

  Swollen 
  at 
  its 
  base 
  it 
  narrowed 
  and 
  then 
  enlarged 
  into 
  an 
  apex 
  

   which 
  was 
  slightly 
  lobed 
  (FiG. 
  3). 
  This 
  structre 
  continued 
  to 
  

   elongate 
  and 
  formed 
  a 
  flat, 
  cellular 
  mass 
  which 
  was 
  lobed 
  (Figs. 
  

   4, 
  5). 
  From 
  near 
  its 
  base 
  and 
  on 
  one 
  side 
  of 
  the 
  structure 
  pro- 
  

   liferations 
  of 
  a 
  thallus-like 
  character 
  developed. 
  

  

  The 
  prothallium 
  in 
  the 
  culture 
  of 
  le, 
  which 
  gave 
  rise 
  to 
  the 
  

   apogamous 
  outgrowth, 
  was 
  wedge-shaped 
  with 
  an 
  obtuse 
  apex 
  

   without 
  a 
  sinus 
  (Fig. 
  6). 
  As 
  in 
  the 
  previous 
  cases 
  described 
  the 
  

   apogamous 
  outgrowth 
  developed 
  as 
  a 
  swelling 
  from 
  the 
  meriste- 
  

   matic 
  region. 
  This 
  swelling 
  continued 
  to 
  grow, 
  forming 
  a 
  cylin- 
  

   drical 
  process 
  several 
  cells 
  in 
  thickness 
  which 
  became 
  somewhat 
  

   narrower 
  as 
  it 
  developed. 
  

  

  An 
  apogamous 
  outgrowth 
  formed 
  on 
  a 
  prothallium 
  which 
  

   had 
  been 
  transferred 
  from 
  I 
  to 
  la, 
  four 
  weeks 
  after 
  the 
  spores 
  were 
  

   sow^n. 
  This 
  prothallium 
  (Fig. 
  7) 
  was 
  broad 
  and 
  irregular, 
  one 
  lobe 
  

   being 
  much 
  larger 
  than 
  the 
  other. 
  A 
  meristem 
  was 
  present 
  from 
  

   which 
  archegonia, 
  normal 
  in 
  appearance, 
  developed. 
  From 
  the 
  

   margin 
  of 
  the 
  prothallium, 
  where 
  the 
  sinus 
  is 
  usually 
  formed, 
  the 
  

   prothallium 
  continued 
  to 
  grow 
  into 
  a 
  cylindrical 
  cellular 
  structure, 
  

   w^hich 
  finally 
  broadened 
  into 
  a 
  flat 
  thallus-like 
  body 
  one 
  cell 
  in 
  

   thickness 
  with 
  a 
  rounded 
  apex. 
  Tracheids 
  were 
  formed 
  in 
  the 
  

  

  narrow 
  thickened 
  portion. 
  

  

  All 
  three 
  cases 
  of 
  apogamy 
  in 
  0. 
  Clayloniana 
  were 
  observed 
  

   in 
  cultures 
  of 
  lb, 
  where 
  they 
  developed 
  as 
  cellular 
  masses 
  on 
  the 
  

   prothallia 
  (FiGS. 
  8-10). 
  One 
  of 
  these 
  cellular 
  masses, 
  formed 
  

   as 
  a 
  swelling 
  from 
  the 
  meristem 
  near 
  the 
  center 
  of 
  a 
  heart-shaped 
  

  

  1 
  

  

  prothallium 
  which 
  was 
  distinctly 
  notched, 
  bore 
  on 
  the 
  side 
  near 
  

   its 
  apex 
  an 
  archegonium 
  (Fig. 
  8), 
  Another 
  of 
  these 
  cellular 
  masses 
  

   (Fig. 
  9) 
  was 
  formed 
  a 
  little 
  to 
  one 
  side 
  of 
  the 
  center 
  of 
  the 
  meristem 
  

   and 
  near 
  the 
  expanded 
  apex 
  of 
  a 
  prothallium. 
  This 
  outgrowth 
  

   began 
  as 
  a 
  swelling 
  of 
  the 
  tissue, 
  which 
  was 
  triangular 
  without 
  a 
  

   sinus, 
  and 
  developed 
  into 
  a 
  mass 
  whose 
  apex 
  was 
  slightly 
  lobed. 
  

   From 
  one 
  side 
  a 
  proliferation 
  of 
  a 
  thallus-like 
  character 
  devel- 
  

   oped. 
  The 
  third 
  cellular 
  mass 
  was 
  formed 
  on 
  a 
  ver>^ 
  irreg- 
  

   ular 
  prothallium 
  (FiG. 
  lo). 
  Although 
  the 
  margin 
  was 
  greatly 
  

   indented 
  in 
  places 
  no 
  apica 
  sinus 
  was 
  present. 
  The 
  apogamous 
  

   outgrowth, 
  as 
  in 
  the 
  other 
  two 
  cases, 
  appeared 
  first 
  as 
  a 
  swelling 
  of 
  

   the 
  meristem 
  and 
  then 
  developed 
  into 
  an 
  Irregular, 
  cylindrical 
  

  

  r 
  

  

  cellular 
  mass 
  whose 
  apex 
  was 
  distinctly 
  bilobed. 
  

  

  