﻿FUNGI 
  AND 
  FUNGOUS 
  DISEASES 
  OF 
  PLANTS 
  259 
  

  

  245. 
  Different 
  forms 
  and 
  habits 
  of 
  mushrooms. 
  While 
  the 
  

   types 
  of 
  mushrooms 
  already 
  discussed 
  and 
  shown 
  in 
  the 
  illus- 
  

   trations 
  are 
  probably 
  most 
  common 
  of 
  all, 
  others 
  are 
  almost 
  

  

  equally 
  abundant. 
  A 
  common 
  form 
  

   is 
  Polyporus 
  (many 
  pores) 
  (fig. 
  182), 
  

   which 
  appears 
  in 
  shelf 
  -like 
  outgrowths 
  

   from 
  bodies 
  of 
  trees 
  within 
  which 
  

   its 
  mycelium 
  grows. 
  It 
  is 
  commonly 
  

  

  

  

  FIG. 
  201. 
  Basidia 
  and 
  spores 
  

   of 
  a 
  mushroom 
  

  

  Magnified 
  370 
  diameters. 
  After 
  

   A. 
  H. 
  R. 
  Buller 
  

  

  spoken 
  of 
  as 
  one 
  of 
  the 
  

   tree-destroying 
  fungi. 
  

   The 
  mycelium 
  is 
  able 
  to 
  

   penetrate 
  through 
  woody 
  

   tissues 
  and 
  to 
  extend 
  for 
  

   great 
  distances 
  within 
  

   the 
  host 
  plant. 
  It 
  may 
  

   infect 
  a 
  living 
  tree 
  when 
  

   a 
  broken 
  limb 
  or 
  other 
  

   injury 
  offers 
  an 
  entrance, 
  

   live 
  within 
  it 
  during 
  the 
  

   life 
  of 
  the 
  tree, 
  and 
  

   thereafter 
  help 
  to 
  bring 
  

   about 
  the 
  decay 
  of 
  the 
  

   tree. 
  The 
  shelf-like 
  re- 
  

   productive 
  portion, 
  in- 
  

   stead 
  of 
  bearing 
  gills 
  

   on 
  the 
  under 
  surface, 
  

   has 
  many 
  small 
  pores 
  within 
  which 
  spores 
  are 
  formed. 
  The 
  

   number 
  of 
  these 
  spores 
  is 
  very 
  great 
  ; 
  one 
  authority 
  1 
  estimates 
  

   1 
  Buller, 
  A. 
  H. 
  R., 
  Researches 
  on 
  Fungi. 
  Longmans, 
  Green 
  & 
  Co., 
  1909. 
  

  

  FIG. 
  202. 
  Puff 
  balls 
  

  

  Two 
  species 
  of 
  puff 
  balls 
  of 
  the 
  genus 
  Li/cr>penl<ni. 
  

  

  Those 
  above 
  are 
  one 
  half 
  natural 
  size; 
  that 
  

  

  below 
  is 
  two 
  ninths 
  natural 
  size 
  

  

  