As^PteX'r,P1i9iT't      Rhus  Glabra  and  Rhus  Typhina.  401 
being  very  sharp  pointed  and  with  very  thick  walls.  The  small 
glandular  hairs,  if  present,  are  relatively  few. 
The  stems  of  Rhus  glabra  possess  a  number  of  glandular  hairs 
with  one-  or  two-celled  stalks  and  multicellular  heads.  These  hairs 
are  from  10  to  20  microns  in  length.  There  are  also  quite  a  number 
of  non-glandular  hairs  somewhat  resembling  those  of  the  calyx  but 
are  much  longer  (as  long  as  100  microns).  These  latter  sometimes 
have  partition  walls  near  the  base  dividing  them  into  cells. 
Rhus  Typhina. 
Rhus  typhina  is  commonly  known  as  the  "  staghorn  sumac  "  in 
allusion  to  the  soft  brown  pubescence  covering  the  twigs  and 
branches.  It  is  also  known  as  the  "  vinegar  tree  "  and  "  Virginia 
sumac."  It  may  attain  the  height  of  a  tree,  and  is  usually  found 
growing  in  uplands  in  good  soil,  occasionally  being  found  like  Rhus 
glabra  on  barren  gravelly  banks.  It  is  very  abundant  in  the  eastern 
United  States  and  apparently  sparingly  distributed  west  of  the 
Appalachian  Mountains.  It  is  by  far  more  common  at  the  present 
time  than  Rhus  glabra,  as  the  latter  is  being  destroyed  by  reason 
of  the  construction  of  dwellings  and  also  by  the  railroads  that 
control  much  of  the  land  in  which  it  formerly  grew. 
The  small  branches  of  Rhus  typhina  are  coated  with  long,  soft 
hairs  which  are  pinkish  in  the  spring  and  as  the  stems  grow  older 
the  hairs  become  bright  green,  and  finally  turn  brown  in  the  fall. 
On  the  stems  of  the  second  season  the  hairs  are  short  and  darker 
colored  and  very  characteristic.  The  leaves  and  inflorescence  show 
considerable  resemblance  to  those  of  Rhtis  glabra  (Fig.  2).  The 
flowers  are  either  staminate  or  pistillate  and  occur  on  separate 
plants.  Both  Wood 2  and  Sargent 3  state  that  the  flowers  are 
occasionally  polygamous.  The  fruit  is  a  drupe  resembling  that  of 
Rhus  glabra  in  both  form  and  size  but  is  distinguished  by  being 
covered  with  long,  nearly  straight,  needle-like  crimson  hairs. 
It  might  be  well  at  this  point  to  consider  the  botanical  synonym 
of  Rhus  typhina.  In  the  Linnean  herbarium  there  is  preserved  a 
specimen  of  the  staghorn  sumac  in  which  the  inflorescence  is  trans- 
formed into  contorted  bracts.  This  phenomena  is  not  at  all  infre- 
quent in  this  species  and  Linneaus  in  1753  described  this  plant  as 
Datisca  hirta.  Seven  years  later  he  described  perfect  specimens 
.of  the  staghorn  sumac  as  Rhus  typhina.    By  reason  of  the  law 
