﻿Vol. 
  47 
  

  

  No. 
  10 
  

  

  BULLETIN 
  

  

  OF 
  THE 
  

  

  TORREY 
  BOTANICAL 
  CLUB 
  

  

  OCTOBER, 
  1920 
  

  

  Phytogeographical 
  notes 
  on 
  the 
  Rocky 
  Mountain 
  region 
  

   IX. 
  Wooded 
  formations 
  of 
  the 
  Montane 
  Zone 
  of 
  the 
  Southern 
  Rockies 
  

  

  * 
  p. 
  A, 
  Rydberg 
  

  

  The 
  Montane 
  or 
  Canadian 
  Zone 
  extends 
  In 
  Central 
  Colorado 
  

   approximately 
  between 
  the 
  altitudes 
  of 
  2,500 
  and 
  3,000 
  m. 
  In 
  

   the 
  upper 
  part 
  of 
  the 
  zone 
  naturally 
  many 
  of 
  the 
  Subalpine 
  

   plants 
  are 
  common 
  and 
  the 
  lower 
  part 
  has 
  been 
  invaded 
  by 
  those 
  

   of 
  the 
  foothills 
  and 
  plains. 
  Many 
  of 
  these 
  plants 
  have 
  been 
  

   omitted 
  in 
  this 
  discussion. 
  As 
  the 
  Montane 
  and 
  Subalpine 
  Zones 
  

   are 
  predominantly 
  wooded, 
  the 
  plant 
  associations 
  are 
  somewhat 
  

   similar. 
  In 
  the 
  open 
  lands 
  or 
  grass-formations 
  they 
  are 
  more 
  

   unlike 
  so 
  far 
  as 
  the 
  composition 
  of 
  the 
  vegetation 
  is 
  concerned, 
  

   the 
  Montane 
  being 
  more 
  like 
  the 
  plains 
  and 
  mesas 
  of 
  the 
  Sub- 
  

   montane 
  Zone, 
  and 
  the 
  Subalpine 
  more 
  like 
  the 
  Alpine 
  Zone. 
  

  

  The 
  principal 
  forest 
  trees 
  of 
  this 
  zone 
  are 
  the 
  following: 
  

   bull 
  pine 
  (Pimis 
  scopuloncm) 
  , 
  lodge-pole 
  pine 
  (P. 
  Mtirrayana), 
  

   limber 
  pine 
  (P. 
  flexilis), 
  Douglas 
  fir 
  {Pseiidotsuga 
  mucronata), 
  

   Engelmann 
  spruce 
  {Picea 
  Engelmannii), 
  Colorado 
  blue 
  spruce 
  

   (P. 
  Parryana) 
  , 
  bfilsam 
  fir 
  (Abies 
  concolor), 
  narrow-leaved 
  cotton- 
  

   wood 
  {Poptdtis 
  angustifolia) 
  , 
  balsam 
  poplar 
  (?. 
  halsamifera) 
  ,' 
  

   western 
  black 
  birch 
  {Betula 
  fontinaUs), 
  Rocky 
  Mountain 
  alder 
  

   (Alniis 
  tenuifolia), 
  and 
  smooth 
  maple 
  {Acer 
  glabrum). 
  These 
  

   have 
  been 
  discussed 
  in 
  a 
  previous 
  paper.* 
  To 
  these 
  may 
  be 
  added 
  

   several 
  species 
  of 
  willow, 
  hawthorn, 
  and 
  chokecherry, 
  which 
  

  

  ♦ 
  Bull. 
  Torrey 
  Club 
  42: 
  11-25. 
  ipiS* 
  

  

  [The 
  Bulletin 
  for 
  September 
  (47: 
  367-44*^- 
  P^- 
  ^S-t?) 
  ^vas 
  issued 
  October 
  19, 
  

  

  1920.] 
  

  

  441 
  

  

  