﻿14 
  

  

  INTRODUCTION 
  TO 
  BOTANY 
  

  

  coloring 
  substance 
  known 
  as 
  chlorophyll. 
  When 
  the 
  sun 
  shines 
  

   upon 
  the 
  leaf, 
  the 
  chlorophyll 
  absorbs 
  energy 
  from 
  the 
  sun's 
  

   rays. 
  This 
  energy 
  serves 
  to 
  decompose 
  the 
  water 
  and 
  carbon 
  

   dioxide. 
  The 
  products 
  of 
  this 
  decomposition 
  immediately 
  

   reunite, 
  but 
  into 
  new 
  substances, 
  which, 
  after 
  several 
  chemi- 
  

   cal 
  changes, 
  may 
  become 
  sugar 
  or 
  starch. 
  Sugar 
  and 
  starch 
  

   may 
  be 
  used 
  as 
  food 
  by 
  the 
  leaf, 
  or 
  be 
  carried 
  to 
  other 
  parts 
  

   of 
  the 
  plant 
  and 
  used, 
  or 
  be 
  made 
  into 
  more 
  complex 
  foods, 
  

   as 
  oils 
  or 
  protein 
  foods. 
  It 
  is 
  from 
  foods 
  that 
  plants 
  as 
  well 
  

  

  as 
  animals 
  de- 
  

  

  > 
  Stamen 
  

   > 
  Pistil 
  

  

  FKJ. 
  ( 
  J. 
  Diagrams 
  of 
  two 
  flowers 
  

  

  A, 
  entire 
  dower; 
  /,', 
  flower 
  with 
  part 
  of 
  the 
  floral 
  

   structures 
  removed 
  

  

  that 
  makes 
  ac- 
  

   tivity, 
  growth, 
  

   and 
  life 
  itself 
  

   possible. 
  

  

  Since 
  watei 
  

   and 
  carbon 
  di- 
  

   oxide, 
  the 
  sub- 
  

   stances 
  from 
  

   which 
  a 
  green 
  

   plant 
  thus 
  man- 
  

   ufactures 
  food, 
  

   are 
  substances 
  

  

  that 
  are 
  not 
  ordinarily 
  regarded 
  as 
  foods 
  for 
  other 
  living 
  things, 
  

   this 
  process 
  is 
  far-reaching 
  in 
  its 
  significance. 
  The 
  storage 
  of 
  

   surplus 
  plant 
  food 
  in 
  seeds 
  (fig. 
  12), 
  roots, 
  stems, 
  and 
  leaves 
  

   is 
  also 
  most 
  significant, 
  since 
  our 
  food 
  and 
  many 
  of 
  our 
  

   industries 
  depend 
  upon 
  this 
  surplus 
  material. 
  

  

  12. 
  The 
  flower. 
  In 
  addition 
  to 
  the 
  roots, 
  stems, 
  and 
  leaves, 
  

   Mowers 
  are 
  often 
  conspicuous 
  pails 
  of 
  plants. 
  They 
  are 
  the 
  

   structures 
  liy 
  means 
  of 
  which 
  seeds 
  are 
  produced. 
  In 
  some 
  

   plants 
  but 
  one 
  kind 
  of 
  flower 
  is 
  produced 
  (fig. 
  9); 
  in 
  others 
  

   two 
  kinds 
  are 
  formed 
  digs. 
  10 
  and 
  11). 
  In 
  such 
  a 
  flower 
  as 
  

   that 
  shown 
  in 
  figure 
  '. 
  the 
  outermost 
  and 
  lowest 
  floral 
  parts 
  

   form 
  the 
  calyx, 
  each 
  part 
  being 
  a 
  xc/xt/ 
  ; 
  the 
  parts 
  next 
  above 
  

   the 
  calyx 
  constitute 
  the 
  corona, 
  each 
  part 
  being 
  a 
  petal; 
  above 
  

  

  