﻿st 
  

  

  E 
  

  

  P 
  

  

  FIG. 
  198. 
  Wheat 
  rust 
  (Puccinia 
  yriuninis) 
  

  

  A, 
  part 
  of 
  a 
  wheat 
  plant 
  showing 
  rust 
  spots 
  on 
  the 
  stalk. 
  B, 
  a 
  small 
  section 
  of 
  a 
  

   wheat 
  leaf 
  upon 
  which 
  the 
  parasitic 
  rust 
  is 
  growing 
  : 
  m, 
  mycelial 
  hypha! 
  of 
  the 
  

   rust; 
  y.u, 
  young 
  summer 
  spore, 
  or 
  uredospore 
  ; 
  u, 
  fully 
  formed 
  uredospore; 
  st, 
  

   upright 
  hypha 
  upon 
  which 
  uredospore 
  is 
  formed. 
  C, 
  germination 
  of 
  uredospore: 
  

   st, 
  old 
  hypha; 
  u, 
  old 
  uredospore 
  wall 
  ; 
  m, 
  new 
  mycelial 
  hyphse. 
  D, 
  winter 
  spore, 
  

   or 
  teleutospore 
  : 
  st, 
  hypha 
  ; 
  t, 
  two-celled 
  spore. 
  E, 
  germination 
  of 
  teleutospore 
  (t) 
  : 
  

   st, 
  old 
  hypha; 
  p, 
  new 
  hypha, 
  or 
  the 
  promycelium; 
  s, 
  spores, 
  or 
  sporidia. 
  F, 
  sec- 
  

   tion 
  of 
  the 
  barherry 
  leaf, 
  showing 
  aecidiospore 
  stage 
  of 
  rust: 
  e 
  l 
  upper 
  epidermis, 
  

   and 
  e 
  2 
  lower 
  epidermis; 
  p, 
  wall 
  of 
  cup, 
  or 
  aecidium; 
  s, 
  aecidiospores. 
  All 
  much 
  

   enlarged. 
  Rearranged 
  from 
  Duggar's 
  " 
  Fungous 
  Diseases 
  of 
  Plants 
  " 
  

  

  255 
  

  

  