﻿CONTENTS 
  

  

  A. 
  INTRODUCTION. 
  

  

  LECTURE 
  PAGE 
  

  

  I. 
  Descent 
  : 
  theories 
  of 
  evolution 
  and 
  methods 
  

  

  of 
  investigation 
  1 
  

  

  The 
  theory 
  of 
  descent 
  and 
  of 
  natural 
  se- 
  

   lection. 
  Evolution 
  and 
  adaptation. 
  

   Elementary 
  species 
  and 
  varieties. 
  Meth- 
  

   ods 
  of 
  scientific 
  pedigree-culture. 
  

  

  B. 
  ELEMENTARY 
  SPECIES. 
  

  

  II. 
  Elementary 
  species 
  in 
  nature 
  ... 
  32 
  

   Viola 
  tricolor, 
  Draba 
  verna, 
  Primula 
  

   acaulis, 
  and 
  other 
  examples. 
  Euphorbia 
  

   Ipecacuanha. 
  Prunus 
  maritima. 
  Taraxa- 
  

   cum 
  and 
  Hieracium. 
  

  

  III. 
  Elementary 
  species 
  of 
  cultivated 
  plants. 
  63 
  

   Beets, 
  apples, 
  pears, 
  clover, 
  flax 
  and 
  coco- 
  

   nut. 
  

  

  IV. 
  Selection 
  of 
  elementary 
  species 
  ... 
  92 
  

  

  Cereals. 
  Le 
  Couteur. 
  Running 
  out 
  of 
  

   varieties. 
  Rimpau 
  and 
  Risler, 
  Avena 
  fa- 
  

   tua. 
  Meadows. 
  Old 
  Egyptian 
  cereals. 
  

   Selection 
  by 
  the 
  Romans. 
  Shirreff. 
  Hays. 
  

  

  C. 
  RETROGRADE 
  VARIETIES. 
  

  

  V. 
  Characters 
  of 
  retrograde 
  varieties 
  . 
  . 
  121 
  

   Seed 
  varieties 
  of 
  pure, 
  not 
  hybrid 
  origin. 
  

   Differences 
  from 
  elementary 
  species. 
  

   Latent 
  characters. 
  Ray-florets 
  of 
  com- 
  

  

  

  

  Xlll 
  

  

  