﻿404 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  to 
  determine 
  the 
  extent 
  of 
  the 
  advantage 
  and 
  the 
  range 
  of 
  conditions 
  

   under 
  which 
  Cryptostegia 
  might 
  contribute 
  in 
  establishing 
  planta- 
  

   tions 
  of 
  the 
  Para 
  rubber 
  or 
  other 
  useful 
  trees. 
  The 
  Cryptostegia 
  rub- 
  

   ber 
  might 
  become 
  a 
  byproduct 
  if 
  suitable 
  methods 
  of 
  extraction 
  could 
  

   be 
  developed. 
  Cryptostegia 
  is 
  not 
  a 
  shade 
  plant 
  and 
  would 
  not 
  be 
  

   expected 
  to 
  form 
  a 
  continuous 
  canopy 
  of 
  foliage. 
  The 
  use 
  of 
  cover 
  

   crops 
  in 
  the 
  East 
  Indian 
  rubber 
  plantations 
  had 
  become 
  a 
  general 
  

   practice 
  in 
  recent 
  years, 
  showing 
  that 
  a 
  very 
  dense 
  shade 
  is 
  not 
  

   formed. 
  

  

  THE 
  AFRICAN 
  RUBBER 
  TREE 
  IN 
  SHELTER 
  BELTS 
  

  

  Another 
  member 
  of 
  the 
  dogbane 
  family, 
  the 
  African 
  rubber 
  tree 
  

   Funtumia 
  elastica, 
  may 
  serve 
  cultural 
  purposes 
  quite 
  distinct 
  from 
  

   those 
  served 
  by 
  Cryptostegia. 
  Shelter 
  belts 
  are 
  often 
  needed 
  in 
  

   tropical 
  cultures, 
  not 
  only 
  as 
  soil 
  covers 
  and 
  windbreaks, 
  but 
  also 
  for 
  

   excluding 
  other 
  vegetation. 
  Barriers 
  against 
  grass 
  or 
  other 
  weeds 
  

   may 
  be 
  very 
  important 
  for 
  fire 
  protection 
  or 
  for 
  other 
  reasons. 
  The 
  

   behavior 
  of 
  Funtumia 
  in 
  Haiti 
  and 
  in 
  Florida 
  shows 
  several 
  adaptive 
  

   characters 
  that 
  may 
  make 
  it 
  useful 
  for 
  planting 
  with 
  other 
  trees. 
  

   One 
  of 
  these 
  characters 
  is 
  the 
  formation 
  of 
  a 
  close, 
  continuous 
  leaf 
  

   crown 
  or 
  canopy 
  of 
  foliage 
  which 
  does 
  not 
  admit 
  enough 
  sunlight 
  

   to 
  enable 
  plants 
  to 
  grow 
  beneath 
  it, 
  so 
  that 
  grass 
  and 
  weeds 
  are 
  

   excluded. 
  Projects 
  for 
  reforestation 
  with 
  rubber 
  trees 
  or 
  establishing 
  

   rubber 
  reserves 
  may 
  be 
  assisted 
  by 
  using 
  borders 
  or 
  barriers 
  of 
  

   Funtumia. 
  Mechanical 
  extraction 
  of 
  the 
  rubber 
  from 
  the 
  bark 
  is 
  

   likely 
  to 
  prove 
  practicable, 
  as 
  with 
  Castilla, 
  if 
  Funtumia 
  should 
  be 
  

   grown 
  in 
  sufficient 
  quantities 
  for 
  such 
  a 
  process 
  to 
  be 
  developed. 
  

  

  A 
  HARDY 
  GUTTA-PERCHA 
  TREE 
  

  

  A 
  hardy 
  tree 
  from 
  central 
  China, 
  Eucommia 
  ulmoides, 
  has 
  been 
  

   studied 
  in 
  several 
  European 
  countries 
  as 
  a 
  potential 
  source 
  of 
  rubber 
  

   and 
  has 
  been 
  found 
  to 
  thrive 
  in 
  numerous 
  localities 
  in 
  the 
  United 
  

   States 
  from 
  Massachusetts 
  to 
  California. 
  No 
  lack 
  of 
  hardiness 
  is 
  

   indicated, 
  but 
  the 
  sexes 
  are 
  on 
  separate 
  trees 
  and 
  relatively 
  few 
  

   cases 
  of 
  seed 
  production 
  have 
  been 
  reported. 
  At 
  Lanham, 
  Md., 
  seeds 
  

   are 
  produced 
  in 
  normal 
  seasons, 
  but 
  all 
  the 
  flowers 
  may 
  be 
  killed 
  

   by 
  late 
  frosts. 
  The 
  seeds 
  are 
  winged 
  and 
  are 
  widely 
  disseminated, 
  

   but 
  only 
  a 
  few 
  self-sown 
  plants 
  have 
  appeared. 
  Only 
  one 
  volunteer 
  

   tree 
  has 
  grown 
  well 
  — 
  this 
  in 
  an 
  open 
  place. 
  Tolerance 
  of 
  shade 
  is 
  

   not 
  indicated. 
  

  

  Latex 
  tubes 
  are 
  not 
  found 
  in 
  Eucommia, 
  but 
  a 
  rubberlike 
  substance 
  

   is 
  formed 
  in 
  small 
  chambers 
  of 
  the 
  bark, 
  leaves, 
  and 
  seed 
  capsules, 
  

   a 
  substance 
  that 
  dissolves 
  and 
  precipitates 
  with 
  the 
  same 
  chemical 
  

   reagents 
  that 
  are 
  used 
  with 
  rubber 
  and 
  gutta-percha. 
  The 
  Eucommia 
  

  

  