﻿Smithsonian 
  Report. 
  1943. 
  — 
  Cook 
  

  

  Plate 
  14 
  

  

  3bL> 
  -*» 
  

  

  

  

  A 
  Desert 
  Milkweed, 
  asclepias 
  subulata. 
  Containing 
  Rubber. 
  

  

  Upper, 
  wild 
  plants 
  growing 
  with 
  cacti 
  near 
  Superior, 
  Ariz. 
  Lower, 
  left, 
  rootstocks 
  and 
  upright 
  stems, 
  

   natural 
  size; 
  right, 
  experimental 
  cultivation 
  as 
  a 
  field 
  crop. 
  The 
  stems 
  are 
  straight 
  and 
  slender 
  like 
  grass 
  

   stalks, 
  with 
  minute 
  nonfunctional 
  leaves 
  that 
  soon 
  fall 
  oft. 
  

  

  