﻿Miller: 
  The 
  wood 
  of 
  Machaerium 
  Whitfordii 
  77 
  

  

  membranes 
  exhibit 
  a 
  peculiar 
  dotted 
  appearance 
  quite 
  distinct 
  

  

  + 
  

  

  under 
  the 
  low 
  power. 
  These 
  are 
  due 
  to 
  sieve-like 
  perforations, 
  

   first 
  described 
  by 
  Jonsson* 
  in 
  various 
  woods 
  of 
  the 
  Leguminosae 
  

   and 
  certain 
  other 
  families. 
  

  

  . 
  f 
  

  

  Tracheids. 
  — 
  ^Typical 
  tracheids, 
  i.e. 
  with 
  pointed 
  and 
  over- 
  

   lapping 
  ends, 
  are 
  apparently 
  absent. 
  At 
  intervals 
  in 
  the 
  smallest 
  

   vessels, 
  however, 
  it 
  is 
  not 
  uncommon 
  to 
  find 
  cells 
  corresponding 
  in 
  

   every 
  way 
  to 
  segments 
  except 
  that 
  the 
  ends 
  are 
  pitted 
  instead 
  of 
  

   perforated. 
  Intermediate 
  forms 
  with 
  one 
  end 
  perforated 
  and 
  

  

  the 
  other 
  closed, 
  except 
  for 
  bordered 
  pits, 
  are 
  occasionally 
  met 
  

   with. 
  

  

  Wood 
  fibers. 
  — 
  Libriform 
  

  

  mass 
  

  

  mm 
  

  

  the 
  med 
  

  

  the 
  thickness 
  of 
  the 
  wall 
  

  

  * 
  L 
  

  

  about 
  2.5 
  fjL. 
  The 
  lumina 
  are 
  narrow 
  and 
  nonseptate. 
  In 
  cross 
  

   section 
  (Fig. 
  2) 
  the 
  fibers, 
  which 
  are 
  polygonal 
  in 
  outline, 
  appear 
  

   crowded 
  together 
  without 
  regular 
  arrangement, 
  but 
  upon 
  close 
  

   inspection 
  there 
  is 
  usually 
  seen 
  a 
  fairly 
  definite 
  arrangement 
  

   between 
  the 
  larger 
  cavities 
  (the 
  enlarged 
  portions 
  of 
  the 
  fibers) 
  

   and 
  the 
  smaller 
  ones 
  (the 
  dove-tailing 
  tips), 
  due 
  to 
  the 
  fact 
  that 
  

  

  the 
  fibers 
  are 
  storied. 
  

  

  The 
  pits 
  are 
  slit-like 
  or 
  narrowly 
  lenticular, 
  either 
  simple 
  or 
  

   inconspicuously 
  bordered. 
  They 
  are 
  often 
  aggregated 
  in 
  groups 
  of 
  

   seven 
  to 
  eight 
  at 
  the 
  projecting 
  "shoulder" 
  of 
  the 
  fibers, 
  midway 
  

   between 
  vertical 
  ray 
  tiers; 
  see 
  Figs. 
  4 
  and 
  5. 
  These 
  localized 
  pit 
  

   areas, 
  which 
  may 
  be 
  seen 
  In 
  both 
  longitudinal 
  sections, 
  serve 
  to 
  

   make 
  the 
  "ripple 
  marks" 
  more 
  distinct. 
  This 
  feature 
  has 
  

   already 
  been 
  noted 
  by 
  Recordf 
  and 
  corresponds 
  to 
  the 
  condition 
  

   observed 
  by 
  Von 
  HohnelJ 
  in 
  a 
  few 
  woods, 
  notably 
  Bocoa 
  provacen- 
  

  

  sis 
  Aubl. 
  {Inocarpus 
  edulis 
  Forst.). 
  

  

  Wood 
  parenchyma. 
  — 
  Wood 
  parenchyma 
  occurs 
  in 
  three 
  ar- 
  

   rangements: 
  (i) 
  as 
  isolated 
  strands 
  scattered 
  in 
  the 
  prosen- 
  

  

  * 
  Jonsson, 
  B. 
  Siebanliche 
  Poren 
  in 
  den 
  trachealen 
  Xylemelementen 
  der 
  

   Phanerogamen, 
  hauptsachlich 
  der 
  Leguminosen. 
  Ber. 
  Deuts. 
  Bot. 
  Ges. 
  lo: 
  494-513- 
  

  

  1892, 
  

  

  t 
  Record. 
  S. 
  J. 
  , 
  Storied 
  or 
  tier-like 
  structure 
  of 
  certain 
  dicotyledonous 
  woods. 
  

  

  Bull. 
  Torrey 
  Club 
  46: 
  253-273- 
  I9i9- 
  

  

  t 
  HShnel. 
  F. 
  von. 
  Ueber 
  stockwerkartig 
  aufgebaute 
  IlolzkSrper. 
  Sitzb. 
  Math. 
  

  

  Naturw. 
  CI. 
  Akad. 
  Wiss. 
  Wien 
  89: 
  30-47- 
  1884. 
  

  

  