554 
North  American  Conifer  02. 
( Am.  Jour.  Pharm. 
X     October,  1896. 
A  CONTRIBUTION  TO  THE  KNOWLEDGE  OF  SOME 
NORTH  AMERICAN  CONIFERS. 
By  Edson  S.  Bastin  and  Henry  Trimble. 
{Continued  from  page  422.) 
GENERAL  CHARACTERS  OF  THE  GENUS  ABIES. 
The  most  important  distinctions  between  this  genus  and  that  of 
Picea,  already  described,  are  the  following:  (i)  the  leaves  are  flat, 
instead  of  quadrangular ;  (2)  although  spirally  inserted  as  in  Picea, 
they  are,  on  the  horizontal  branches,  usually  deflected  laterally, 
appearing  two-ranked  or  pectinately  arranged ;  (3)  the  leaf-scars  do 
not  project  and  are  nearly  circular  in  outline ;  (4)  there  are  no  resin- 
ducts  in  the  xylem  ;  (5)  the  cones  are  erect  and  arranged  on  the 
upper  sides  of  spreading  branches. 
ABIES  BALSAMEA,  LINK. 
DISTRIBUTION  AND  GENERAL  CHARACTERS. 
This  is  our  common  balsam  fir,  or,  as  it  is  also  called,  the  balm  of 
Gilead  fir.  It  occurs  throughout  our  Northern  borders,  from  Maine 
to  Minnesota,  and  northward  to  Hudson's  Bay,  and  on  the  eastern 
slope  of  the  Rocky  Mountains  of  British  America  and  the  Northern 
United  States.  It  also  occurs  in  New  Brunswick,  Nova  Scotia  and 
Newfoundland.  The  tree  attains  a  height  of  from  60  to  90  feet,  and 
a  diameter  near  its  base  of  from  18  to  24  inches.  It  thrives  best  in 
rather  swampy  soil,  or  at  least  where  there  is  an  abundant  supply  of 
water.  Its  trunk  is  smooth,  dark  grayish-brown,  with  numerous 
balsam  blisters  in  the  bark,  and  showing  from  the  outside;  it  is  very 
straight  and  has  numerous  whorled,  horizontally  spreading  branches, 
which  gradually  diminish  in  length  upwards,  so  that  the  top  is  very 
symmetrically  spire- shaped.  The  bark  strips  readily,  the  wood  is 
white  or  very  light  brown,  the  heart-wood  but  slightly  darker  than 
the  sap-wood.  The  wood  is  of  low  specific  gravity,  soft,  but  com- 
pact, and  not  very  durable.  No  large  tap-root  is  formed,  but  the 
roots  spread  out  horizontally  near  the  surface.  They  are  covered 
with  a  deep  red  bark,  which  at  the  surface  peels  off  in  scales. 
MICROSCOPICAL  STRUCTURE. 
Sections  of  a  twig  two  years  old  showed  the  following  character- 
istics :  The  middle  bark  contained  numerous  secretion  reservoirs 
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