﻿406 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  arate 
  and 
  show 
  green 
  color 
  on 
  March 
  13, 
  when 
  Gorylus 
  flowers 
  were 
  

   well 
  advanced, 
  with 
  many 
  empty 
  stamens. 
  The 
  Eucommia 
  stamens 
  

   are 
  deep 
  green 
  and 
  notably 
  accrescent, 
  becoming 
  only 
  slightly 
  yellow- 
  

   ish 
  at 
  maturity. 
  A 
  length 
  of 
  8 
  to 
  10 
  mm. 
  is 
  attained, 
  with 
  the 
  fila- 
  

   ments 
  1 
  to 
  2 
  mm. 
  long, 
  the 
  receptacle 
  2 
  to 
  4 
  mm. 
  The 
  number 
  of 
  

   stamens 
  on 
  one 
  receptacle 
  varies 
  from 
  3 
  to 
  10, 
  usually 
  6, 
  7, 
  or 
  8, 
  with 
  

   6 
  as 
  the 
  modal 
  number. 
  

  

  The 
  pistils 
  and 
  fruits 
  are 
  green, 
  those 
  that 
  are 
  not 
  fertilized, 
  or 
  at 
  

   least 
  not 
  fertile, 
  often 
  persisting 
  with 
  the 
  fertile 
  fruits, 
  not 
  growing 
  

   as 
  large 
  but 
  retaining 
  a 
  deeper 
  green 
  color. 
  The 
  fertile 
  fruits 
  exceed 
  

   4 
  cm. 
  in 
  length, 
  the 
  infertile 
  3 
  cm. 
  The 
  large, 
  straight 
  embryo 
  is 
  en- 
  

   closed 
  in 
  a 
  hard 
  shell 
  near 
  the 
  middle 
  of 
  the 
  fruit, 
  shown 
  in 
  plate 
  15. 
  

   Two 
  collateral 
  ovules 
  develop 
  in 
  the 
  unfertilized 
  fruits 
  to 
  a 
  length 
  of 
  

   about 
  3 
  mm., 
  noted 
  as 
  still 
  living 
  on 
  July 
  23, 
  when 
  the 
  fertile 
  fruits 
  

   were 
  nearly 
  full 
  size 
  but 
  immature. 
  The 
  seeds 
  ripen 
  in 
  September 
  

   or 
  October, 
  but 
  do 
  not 
  fall 
  until 
  a 
  rather 
  severe 
  frost 
  has 
  occurred 
  — 
  

   in 
  Maryland 
  about 
  the 
  middle 
  of 
  November. 
  The 
  female 
  tree 
  may 
  

   defoliate 
  2 
  or 
  3 
  weeks 
  in 
  advance 
  of 
  the 
  male, 
  while 
  the 
  fruits 
  are 
  

   still 
  in 
  place. 
  

  

  The 
  Eucommia 
  tree 
  is 
  now 
  placed 
  by 
  botanists 
  as 
  a 
  monotypic 
  

   family 
  Eucommiaceae, 
  apart 
  from 
  any 
  other 
  group, 
  after 
  being 
  as- 
  

   signed 
  provisionally 
  to 
  several 
  other 
  families, 
  such 
  as 
  Magnoliaceae, 
  

   Trochodendraceae, 
  and 
  Hamamelidaceae. 
  The 
  last 
  group, 
  the 
  witch- 
  

   hazel 
  family, 
  is 
  considered 
  as 
  remotely 
  related. 
  

  

  EUCOMMIA 
  SUPPRESSES 
  ALL 
  TERMINAL 
  BUDS 
  

  

  Another 
  special 
  character 
  of 
  Eucommia, 
  adding 
  to 
  the 
  educational 
  

   interest 
  of 
  the 
  tree, 
  is 
  the 
  complete 
  suppression 
  of 
  terminal 
  buds. 
  

   Each 
  branch 
  or 
  twig 
  of 
  Eucommia 
  ends 
  with 
  an 
  internode 
  that 
  de- 
  

   velops 
  only 
  a 
  rudimentary 
  bud, 
  concealed 
  in 
  a 
  minute 
  pit 
  in 
  the 
  leaf 
  

   base. 
  In 
  the 
  absence 
  of 
  a 
  bud, 
  the 
  petiole 
  of 
  the 
  last 
  leaf 
  continues 
  

   in 
  the 
  direction 
  of 
  the 
  branch, 
  instead 
  of 
  being 
  pushed 
  aside 
  to 
  a 
  

   somewhat 
  oblique 
  position 
  by 
  the 
  enlargement 
  of 
  an 
  axillary 
  bud, 
  as 
  

   happens 
  with 
  all 
  the 
  preceding 
  leaves; 
  also, 
  the 
  petiole 
  of 
  the 
  last 
  

   leaf 
  of 
  a 
  shoot 
  or 
  twig 
  of 
  Eucommia 
  is 
  usually 
  longer 
  than 
  that 
  of 
  

   the 
  adjacent 
  leaves. 
  Such 
  an 
  elongate 
  petiole 
  marked 
  at 
  the 
  base 
  by 
  

   the 
  pit 
  enclosing 
  the 
  rudimentary 
  bud 
  is 
  shown 
  in 
  natural 
  size 
  in 
  

   plate 
  15, 
  extending 
  obliquely 
  at 
  the 
  right 
  of 
  the 
  lower 
  figure. 
  

  

  The 
  term 
  "sympodial" 
  might 
  be 
  applied 
  to 
  the 
  branching 
  habit 
  of 
  

   Eucommia, 
  as 
  to 
  plants 
  where 
  terminal 
  buds 
  are 
  replaced 
  by 
  flowers 
  

   or 
  by 
  tendrils, 
  but 
  with 
  Eucommia 
  there 
  is 
  no 
  replacement, 
  the 
  apical 
  

   internode 
  being 
  merely 
  deprived 
  of 
  its 
  bud 
  and 
  then 
  appearing 
  as 
  a 
  

   sterile 
  lateral 
  stub 
  after 
  a 
  new 
  shoot 
  has 
  grown 
  from 
  the 
  subterminal 
  

   bud. 
  

  

  