﻿MOSSES, 
  LIVERWORTS, 
  AND 
  FERNS 
  

  

  275 
  

  

  toward 
  the 
  antheridia. 
  The 
  enlarged 
  part 
  of 
  an 
  archego- 
  

   nium, 
  where 
  the 
  egg 
  is 
  formed, 
  is 
  imbedded. 
  The 
  neck 
  opens, 
  

   sperms 
  enter, 
  and 
  one 
  of 
  the 
  sperms 
  unites 
  with 
  the 
  egg. 
  The 
  

   result 
  is 
  the 
  formation 
  of 
  an 
  oospore, 
  which 
  is 
  inclosed 
  in 
  the 
  

   tissue. 
  Since 
  this 
  heart-shaped 
  plant 
  produced 
  the 
  sex 
  cells, 
  

   it 
  is 
  the 
  gamete 
  plant, 
  or 
  gametophyte, 
  and 
  since 
  the 
  asexual 
  

   spores 
  are 
  formed 
  upon 
  the 
  leafy 
  fern 
  plant, 
  that 
  is 
  the 
  spo- 
  

   rophyte. 
  The 
  asexual 
  spore 
  germinates 
  and 
  produces 
  the 
  ga- 
  

   metophyte, 
  and 
  the 
  oospore 
  germinates 
  and 
  produces 
  the 
  leafy 
  

  

  FIG. 
  213. 
  Fern 
  antheridium, 
  with 
  sperms 
  FIG. 
  214. 
  Archegonium 
  of 
  a 
  f 
  ern 
  

   Greatly 
  magnified 
  Greatly 
  magnified 
  

  

  sporophyte. 
  The 
  young 
  leafy 
  plant 
  at 
  first 
  appears 
  as 
  if 
  it 
  grew 
  

   directly 
  from 
  the 
  heart-shaped 
  gametophyte 
  (fig. 
  212). 
  It 
  soon 
  

   develops 
  leaves 
  and 
  roots 
  and 
  an 
  underground 
  stem 
  - 
  - 
  in 
  short, 
  

   is 
  a 
  new 
  leafy 
  fern 
  plant. 
  

  

  It 
  must 
  be 
  clear 
  that 
  in 
  ferns 
  there 
  is 
  the 
  same 
  kind 
  of 
  alter- 
  

   nation 
  between 
  the 
  sexual 
  and 
  asexual 
  generations 
  of 
  the 
  plant 
  

   as 
  that 
  seen 
  in 
  the 
  mosses, 
  except 
  that 
  in 
  the 
  ferns 
  each 
  stage 
  of 
  

   the 
  plant 
  lives 
  for 
  a 
  time 
  quite 
  independent 
  of 
  the 
  other 
  stage. 
  

  

  260. 
  Significance 
  of 
  fibrovascular 
  tissue. 
  It 
  is 
  evident 
  that 
  

   a 
  fern 
  leaf 
  exposes 
  much 
  chlorophyll 
  to 
  the 
  light 
  --much 
  

   more 
  than 
  does 
  any 
  plant 
  among 
  the 
  bryophytes. 
  The 
  strong 
  

   supporting 
  and 
  conducting 
  tissues 
  of 
  the 
  leaf 
  uphold 
  the 
  

  

  