24 
North  American  Coniferce. 
/  A.m.Jour.  Pharm. 
\    January,  1896. 
(c)  Tsuga,  the  Hemlocks,  or  Hemlock  Spruces. — These  have  flat 
foliage  leaves,  which  are  whitened  beneath,  and  disposed  horizontally 
in  two  rows.  The  midrib  stands  out  prominently  on  the  lower  sur- 
face, and  is  correspondingly  depressed  on  the  upper.  The  stami- 
nate  flowers  in  nearly  globose  clusters ;  the  pollen-sacs  dehiscing 
transversely.  The  fertile  cones  mature  the  first  year,  are  pendulous 
on  the  branches,  and  the  scales  are  thin  and  persistent.  T.  Cana- 
densis is  our  Eastern  hemlock,  whose  bark  is  so  much  employed  in 
tanning.  T.  Mertensiana  and  T.  Pattoniana  are  West  American 
species,  and  T.  Sieboldii  is  a  Japan  species. 
(d)  Pseudotsuga,  the  False  Hemlock  Spruces. — Leaves  flattened, 
short-petoliate ;  macrosporangiate  scales  much  longer  than  the  pla- 
cental ones,  thin  and  three  parted ;  microsporangiate  flowers  large, 
and  borne  in  the  axils  of  last  year's  leaves;  flower  and  leaf- buds 
very  large. 
P.  taxifolia  (the  Douglass  spruce),  and  P.  macrocarpa  (the  big- 
cone  spruce)  are  both  West  American. 
(e)  Larix,  the  Larches. — The  members  of  this  genus  differ  from 
all  the  preceding  Abietinese,  in  having  both  long  and  short  shoots, 
on  which  the  leaves  are  borne;  leaves  on  the  short  shoots  fascicu- 
lately  arranged,  and  on  the  long  shoots  spirally,  deciduous  in  the 
autumn  ;  branches  not  whorled  ;  both  starrtinate  and  pistillate  flow- 
ers terminal  on  short  leafy  shoots ;  cones  pendent  and  maturing  in 
one  season.  Examples  are  :  L  Americana  (the  American  larch  or 
tamarack),  L.  Europaea  (the  European  larch,  commonly  cultivated), 
L.  occidentalis  and  L.  Lyellii,  West  American  species. 
(/)  Cedrus,  the  True  Cedars. — They  have  the  general  aspect  of 
the  larches,  but  have  evergreen  leaves,  and  require  two  years  to  de- 
velop their  seeds.  The  cones  are  large,  erect  and  depressed  at  the 
ends.  There  are  three  species,  all  oriental :  C.  Libani,  C.  Atlantica 
and  C.  Deodara. 
is)  Pznus>  the  Pines- — The  leaves  needle-like,  evergreen,  in  fasci- 
cles of  from  two  to  five,  with  a  basal  sheath  composed  of  scales ; 
branches  falsely  whorled  ;  the  microsporangiate  scales  compactly 
arranged  in  cones  and  taking  the  place  of  dwarf  shoots  at  the  base  of 
a  long  shoot  of  the  same  season ;  the  conical,  globose,  oblong  or 
cylindrical  fruit  cones  ripening  in  two  years,  and  bearing  thick, 
usually  woody,  placental  scales,  which  are  expanded  at  their  free 
ends  into  a  flattish  surface  or  apophysis. 
