﻿1890.] 
  

  

  BOTANICAL 
  GAZETTE. 
  jq;; 
  

  

  w 
  

  

  4 
  

  

  The 
  almost 
  infertile 
  condition 
  of 
  the 
  large 
  stamen 
  reminds 
  

   one 
  of 
  the 
  structure 
  of 
  the 
  stamens 
  of 
  the 
  cultured 
  potatoes. 
  

   In 
  these, 
  while 
  large 
  and 
  plump, 
  there 
  is 
  almost 
  no 
  pollen- 
  

   beanng 
  layer, 
  and 
  usually 
  no 
  apical 
  pore 
  opens 
  for 
  the 
  dis- 
  

   charge 
  of 
  pollen. 
  In 
  an 
  article 
  presented 
  by 
  the 
  writer 
  last 
  

   year 
  upon 
  the 
  low 
  seed-producing 
  capacity 
  of 
  potatoes, 
  these 
  

   plump 
  but 
  sterile 
  stamens 
  were 
  looked 
  upon 
  as 
  a 
  sort 
  of 
  fat- 
  

   ty 
  degeneracy, 
  brought 
  about 
  by 
  high 
  culture 
  and 
  the 
  lack 
  

   of 
  any 
  demand 
  for 
  seed 
  production 
  for 
  the 
  preservation 
  of 
  

   the 
  plant 
  under 
  the 
  conditions 
  which 
  obtain 
  with 
  potato 
  

   growers. 
  

  

  The 
  horse 
  nettle 
  (Solanum 
  Carolinense) 
  has 
  a 
  form 
  of 
  ma- 
  

   ture 
  anther 
  that 
  was 
  at 
  first 
  sight 
  a 
  marked 
  variation 
  from 
  

   the 
  type. 
  It 
  dehisces 
  by 
  a 
  pore, 
  and 
  we 
  should 
  expect 
  that 
  

   there 
  would 
  be 
  but 
  a 
  single 
  pollen 
  cavity 
  for 
  each 
  half 
  of 
  the 
  

   anther. 
  Instead 
  of 
  this 
  there 
  are 
  two, 
  and 
  a 
  seeming 
  tend- 
  

   ency 
  to 
  produce 
  four. 
  The 
  explanation 
  is 
  again 
  found 
  in 
  

   the 
  shrinking 
  of 
  tissue 
  by 
  drying, 
  as 
  may 
  be 
  quickly 
  seen 
  by 
  

   comparing 
  the 
  old 
  with 
  young 
  anthers. 
  A 
  section 
  of 
  a 
  young 
  

   anther 
  is 
  shown 
  at 
  a 
  in 
  fig. 
  4, 
  and 
  the 
  position 
  of 
  the 
  dried 
  

   parts 
  m 
  a 
  mature 
  stamen 
  is 
  seen 
  at^. 
  The 
  two 
  theca; 
  do 
  not 
  

   become 
  joined 
  by 
  the 
  obliteration 
  of 
  the 
  wall 
  between 
  them, 
  

   i^ut 
  this 
  septum 
  is 
  reduced 
  by 
  drying 
  to 
  a 
  tough 
  membrane, 
  

   and 
  the 
  columella— 
  not 
  large 
  in 
  this 
  species— 
  is 
  reduced 
  in 
  

   the 
  same 
  way 
  to 
  a 
  slender 
  projection, 
  one 
  upon 
  each 
  side, 
  

   and 
  into 
  their 
  respective 
  thecae. 
  

  

  In 
  the 
  species 
  of 
  Physalis 
  the 
  anthers 
  open 
  near 
  the 
  point 
  

   of 
  union 
  of 
  the 
  valveSj'mid 
  the 
  thin 
  tissue 
  coils 
  upon 
  itselr 
  

   and 
  drops 
  away 
  not 
  unlike 
  the 
  epidermis 
  from 
  a 
  healing 
  blis- 
  

   ter, 
  exposing 
  the 
  pollen 
  as 
  a 
  thin 
  layer 
  upon 
  the 
  thick 
  and 
  

   rather 
  firm 
  columella. 
  This 
  takes 
  place 
  in 
  anthers 
  that 
  in 
  

   lorm 
  and 
  position 
  correspond 
  to 
  those 
  with 
  pores, 
  but 
  both 
  

   the 
  pores 
  and 
  the 
  valvular 
  dehiscence 
  fail 
  and 
  this 
  peculiar 
  

   modification 
  exists 
  instead. 
  

  

  When 
  we 
  come 
  to 
  consider 
  the 
  contents 
  of 
  the 
  theca, 
  the 
  

   uniformity 
  is 
  peculiarly 
  constant 
  in 
  the 
  order. 
  There 
  are 
  some 
  

   difterences 
  in 
  color 
  of 
  the 
  pollen, 
  that 
  is^ 
  while 
  some 
  grains 
  

   are 
  colorless 
  others 
  are 
  tinged 
  slightly 
  with 
  brown, 
  and 
  the 
  

   niarkmgs 
  upon 
  some 
  species 
  are 
  more 
  prominent 
  than 
  oth- 
  

   ers, 
  but 
  obscure 
  at 
  the 
  best. 
  

  

  VVhen 
  dry 
  (figure 
  5, 
  a) 
  the 
  pollen 
  is 
  long 
  egg-shaped, 
  

   ^vith 
  three 
  sutures. 
  B}^ 
  the 
  addition 
  of 
  water 
  an 
  almost 
  

   spherical 
  shape 
  is 
  assumed, 
  and 
  the 
  outer 
  coat, 
  bearing 
  what- 
  

   ever 
  there 
  may 
  be 
  of 
  color 
  and 
  fine 
  markings, 
  becomes 
  sep- 
  

  

  