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Rhus  Glabra  and  Rhus  Typhina. 
{Am.  Jour.  Pharm. 
September,  1913. 
of  priority  the  specific  name  hirta  should  probably  be  used  and 
yet  by  reason  of  long  established  usage  we  may  well  adhere  to  the 
name  which  has  been  most  commonly  used,  namely  Rhus  typhina. 
It  was  used  by  Asa  Gray  4  and  is  still  retained  in  Gray's  Manual 
revised  by  Robinson  and  Fernald  5  in  1908.  Sargent  uses  it  in  his 
Silva  of  North  America  3  and  it  is  also  adopted  by  Engler  and 
Prantl  in  their  Naturlichen  Pflanzenfamilien.0  While  it  is  true  that 
Britton  has  adopted  the  name  of  Rhus  hirta  (Linne7)  Sudworth. 
yet  in  a  note  in  the  Bulletin  of  the  Torrey  Botanical  Club  8  he  says  : 
"  Although  hirta  is  the  oldest  specific  name  associated  with  the  plant, 
we  are  I  think  debarred  from  using  it  by  the  publication  of  Rhus 
hirta  Harv.  as  a  synonym  by  Engler  in  DC.  Monog.  Phan.  IV.  425 
(1883),  where  this  is  referred  to  Rhus  tridentata"  This  is  con- 
firmed in  Index  Kewensis  and  in  which  work  Rhus  typhina  Linne 
also  receives  precedence. 
Our  interest  in  Rhus  typhina  is  that  we  may  be  able  to  detect 
the  fruits  of  this  plant  in  commerce.  Fortunately  this  is  very  easily 
done  as  the  fruits  while  superficially  resembling  those  of  Rhus  glabra 
are  darker  and  covered  with  long  straight  hairs  giving  it  a  character- 
istic spinose  appearance.  The  hairs,  however,  are  not  indurated  and 
are  of  a  soft  downy  texture.  As  a  matter  of  fact  neither  the 
panicle  of  fruits  when  attached  to  the  plant  nor  the  separated  fruits 
in  the  drug  can  be  mistaken  for  Rhus  glabra.  The  hairs  are  long 
lieedle-like,  varying  from  750  to  1500  microns  in  length  (Fig.  1,  t). 
They  are  very  narrow,  gradually  tapering  and  at  the  widest  portion 
at  the  base  do  not  exceed  50  microns  in  width.  In  the  lower  portion 
they  are  sometimes  divided  by  transverse  walls.  The  color  of  the 
cell  sap  and  the  other  contents  resemble  those  of  Rhus  glabra. 
Associated  with  these  hairs  are  small  glandular  hairs  varying  from 
75  to  120  microns  in  length.  The  upper  or  head-portion  is  more  or 
less  globular  or  elliptical  in  outline  and  the  stalk  is  longer  than  in 
Rhus  glabra. 
The  calyx  of  Rhus  typhina  is  covered  with  hairs,  these  being  of 
two  types,  the  glandular  and  non-glandular.  The  stalks  of  the 
glandular  hairs  are  much  longer  than  the  head  portion  and  are 
usually  made  up  of  two  superimposed  cells.  The  non-glandular 
hairs  of  the  calyx  are  similar  to  those  found  on  the  fruits  of  the 
staghorn  sumac  and  may  contain  a  similar  red  colored  cell  sap. 
The  hairs  on  the  stems  of  Rhus  typhina  resemble  those  of  the 
calyx  but  are  much  larger.     The  glandular  hairs  possess  3-  to 
