﻿344 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  lies 
  a 
  large 
  highly 
  dissected 
  plateau 
  ranging 
  downward 
  from 
  about 
  

   4,000 
  feet 
  altitude. 
  It 
  has 
  a 
  warm-temperate 
  climate 
  with 
  more 
  tropi- 
  

   cal 
  conditions 
  in 
  the 
  lower 
  parts 
  of 
  the 
  valley, 
  as 
  along 
  the 
  Yangtze. 
  

   The 
  vegetation 
  of 
  this 
  part 
  of 
  Yunnan 
  is, 
  therefore, 
  subtropical 
  with 
  

   warm-temperate 
  elements. 
  In 
  general, 
  the 
  hills 
  are 
  less 
  denuded 
  

   than 
  in 
  the 
  eastern 
  mountains 
  of 
  China, 
  owing 
  in 
  part 
  to 
  the 
  lesser 
  

   Chinese 
  population 
  and 
  the 
  greater 
  abundance 
  of 
  Thai, 
  Shan, 
  and 
  other 
  

   non-Chinese 
  peoples. 
  These 
  latter 
  inhabitants 
  are 
  less 
  agricultural 
  

   than 
  the 
  Chinese, 
  hence 
  the 
  wild 
  vegetation 
  is 
  less 
  disturbed. 
  They 
  

   do, 
  however, 
  affect 
  the 
  vegetation 
  adversely 
  to 
  some 
  extent 
  by 
  clearing 
  

   the 
  hillsides 
  and 
  cultivating 
  them 
  without 
  terracing 
  or 
  using 
  other 
  

   means 
  to 
  reduce 
  erosion. 
  In 
  2 
  or 
  3 
  years, 
  when 
  the 
  fertile 
  soil 
  is 
  

   washed 
  away, 
  these 
  areas 
  are 
  abandoned 
  and 
  new 
  fields 
  are 
  cleared. 
  

   The 
  abandoned 
  fields 
  may 
  eventually 
  revert 
  to 
  the 
  original 
  forested 
  

   condition, 
  but 
  only 
  after 
  a 
  succession 
  of 
  stages, 
  some 
  of 
  which 
  are 
  very 
  

   undesirable. 
  

  

  Taken 
  as 
  a 
  whole 
  the 
  flora 
  of 
  middle 
  China 
  is 
  warm 
  temperate 
  with 
  

   admixtures 
  of 
  subtropical 
  families, 
  genera, 
  and 
  species. 
  It 
  is 
  rich 
  in 
  

   endemics 
  and 
  includes 
  most 
  of 
  the 
  eastern 
  Asiatic-eastern 
  North 
  Amer- 
  

   ican 
  species 
  and 
  genera 
  (pi. 
  4, 
  fig. 
  2) 
  . 
  The 
  Japanese 
  flora, 
  except 
  for 
  

   that 
  of 
  the 
  more 
  tropical 
  parts, 
  is 
  essentially 
  of 
  the 
  same 
  type 
  as 
  that 
  

   of 
  middle 
  China. 
  

  

  TROPICAL 
  AND 
  SUBTROPICAL 
  SOUTHERN 
  CHINA 
  

  

  In 
  this 
  area 
  is 
  found 
  the 
  extension 
  into 
  China 
  of 
  the 
  tropical 
  or 
  

   subtropical 
  jungle 
  vegetation 
  of 
  Indo-China 
  and 
  the 
  Malayan 
  region. 
  

   The 
  area 
  comprises 
  all 
  or 
  most 
  of 
  Kwangsi, 
  most 
  of 
  Kwangtung, 
  the 
  

   coastal 
  region 
  of 
  Fukien 
  and 
  part 
  of 
  Chekiang 
  and, 
  of 
  course, 
  of 
  

   the 
  islands 
  of 
  Hong 
  Kong 
  and 
  Hainan. 
  The 
  lowland 
  vegetation 
  of 
  

   Formosa 
  and 
  that 
  of 
  tropical 
  Japan 
  are 
  of 
  this 
  type. 
  Climatically 
  

   the 
  region 
  is 
  dominated 
  almost 
  wholly 
  by 
  monsoon 
  winds, 
  which 
  

   bring 
  an 
  abundance 
  of 
  rain 
  from 
  March 
  or 
  April 
  through 
  October, 
  

   with 
  relatively 
  little 
  rain 
  from 
  then 
  till 
  March 
  again. 
  The 
  Nan 
  

   Shan 
  Range 
  on 
  the 
  north 
  cuts 
  off 
  most 
  of 
  the 
  coldest 
  winter 
  winds 
  

   from 
  that 
  direction, 
  so 
  the 
  winters 
  are 
  milder 
  than 
  in 
  middle 
  China. 
  

   Freezing 
  temperatures 
  are 
  very 
  rare 
  near 
  the 
  coast. 
  Judging 
  by 
  

   the 
  jungles 
  still 
  found 
  in 
  Hainan 
  and 
  by 
  the 
  oases 
  of 
  tropical 
  vegeta- 
  

   tion 
  still 
  found 
  in 
  a 
  few 
  remote 
  mountain 
  ravines 
  and 
  around 
  temples, 
  

   and 
  in 
  comparing 
  this 
  area 
  with 
  places 
  in 
  other 
  parts 
  of 
  the 
  world 
  

   which 
  have 
  a 
  similar 
  climate 
  and 
  formations, 
  but 
  which 
  are 
  as 
  yet 
  

   undevastated, 
  it 
  is 
  rather 
  clear 
  that 
  large 
  broadleaved 
  evergreen 
  rain 
  

   forests 
  formerly 
  occurred 
  where 
  we 
  now 
  find 
  only 
  grass-covered 
  hills. 
  

   The 
  amount 
  of 
  cultivated 
  land 
  in 
  this 
  area 
  is 
  relatively 
  small, 
  con- 
  

   sisting 
  mostly 
  of 
  the 
  rich 
  delta 
  of 
  the 
  West, 
  North, 
  and 
  East 
  Rivers 
  

  

  