﻿MOSSES, 
  LIVERWORTS, 
  AND 
  FERNS 
  

  

  279 
  

  

  Modern 
  equisetums 
  live 
  about 
  open 
  marshes, 
  in 
  sandy 
  

   wastes, 
  and 
  along 
  railroad 
  embankments. 
  They 
  have 
  hard, 
  

   rough, 
  siliceous 
  stems, 
  

   with 
  small 
  leaves 
  that 
  

   form 
  sheaths 
  about 
  the 
  

   joints 
  of 
  the 
  stem 
  (fig. 
  

   217). 
  In 
  the 
  most 
  com- 
  

   mon 
  species 
  of 
  Equisetum 
  

   the 
  sporophyll 
  branch 
  

   appears 
  very 
  early 
  in 
  the 
  

   spring 
  and 
  produces 
  at 
  

   its 
  tip 
  the 
  strobilus, 
  or 
  

   cone, 
  which 
  bears 
  the 
  

   sporangia 
  upon 
  greatly 
  

   reduced 
  and 
  transformed 
  

   leaves 
  (sporophylls). 
  The 
  

   bushy 
  chlorophyll 
  branch 
  

   appears 
  later 
  and 
  is 
  the 
  

   one 
  which 
  grows 
  through- 
  

   out 
  the 
  season, 
  the 
  sporo- 
  

   phyll 
  branch 
  disappearing 
  

   as 
  soon 
  as 
  the 
  spores 
  have 
  

   been 
  shed. 
  The 
  spores 
  

   are 
  attached 
  to 
  pecul- 
  

   iar 
  strap-like 
  outgrowths 
  

   known 
  as 
  elaters 
  (driv- 
  

   ers). 
  The 
  elaters 
  are 
  

   supposed 
  to 
  assist 
  in 
  dis- 
  

   tributing 
  the 
  spores. 
  

  

  The 
  bushy 
  foliage, 
  or 
  

   chlorophyll 
  part 
  of 
  the 
  

   plant, 
  grows 
  and 
  depos- 
  

   its 
  food 
  material 
  which 
  

   may 
  be 
  used 
  the 
  next 
  

   season 
  for 
  the 
  growth 
  of 
  

   the 
  sporophyll 
  branch. 
  

  

  FIG. 
  218. 
  A 
  club 
  moss 
  (Lycopodium) 
  

  

  The 
  horizontal 
  rootstock, 
  with 
  its 
  roots, 
  grows 
  

   within 
  or 
  upon 
  the 
  humus. 
  The 
  upright 
  branches 
  

   (.1) 
  bear 
  green 
  leaves 
  and 
  strobili 
  (str) 
  (also 
  

   called 
  spikes 
  or 
  cones) 
  in 
  which 
  spores 
  are 
  

   formed. 
  At 
  C 
  is 
  shown 
  one 
  leaf 
  from 
  the 
  strobi- 
  

   1ns, 
  and 
  upon 
  this 
  leaf 
  is 
  a 
  sporangium. 
  From 
  

   the 
  partially 
  opened 
  sporangium, 
  spores 
  escape. 
  

   B 
  shows 
  enlarged 
  spores 
  

  

  