400  Rhus  Glabra  and  Rhus  Typhina.  {\^teXrPiyiT' 
The  branches  and  leaves  contain  a  milky  juice.  The  leaves  are 
compound,  the  leaflets  being  sharply  serrate,  dark  green  above  and 
whitish  beneath,  and  in  the  fall  they  turn  to  a  bright  scarlet  with 
various  shades  of  crimson,  purple  and  orange.  The  flowers  are  in 
dense  terminal  panicles,  being  staminate  or  pistillate,  the  latter  de- 
veloping into  small  drupes,  which  are  covered  with  short  crimson 
hairs  giving  a  velvety  appearance  to  the  fruits.  The  latter  while 
fully  gi  own  in  August  do  not  ripen  until  October.  Illustrations 
showing  the  panicles  of  fruits  of  Rhus  glabra  will  be  found  in  the 
second  edition  of  my  Text-book  of  Botany  and  Pharmacognosy, 
pp.  321  and  570. 
The  ripe  fruits  collected  in  October  are  official.  They  are  nearly 
globular,  ovoid  or  more  or  less  reniform,  somewhat  compressed  and 
vary  from  2.5  to  4  mm.  in  length  and  from  2  to  4  mm.  in  width. 
Externally  they  are  dark  red  and  velvety  with  short  hairs.  The 
summit  is  usually  surmounted  with  a  short  style,  and  at  the  base 
there  is  not  infrequently  seen  the  5-cleft  calyx  attached  to  a  short 
stalk  or  peduncle.  The  fruit  is  one-locular  and  one-seeded,  inodor- 
ous, but  when  fresh  with  an  odor  of  green  apples.  The  fruits  have 
an  acidulous  and  slightly  astringent  taste  due  to  the  principles  in  the 
hairs. 
The  hairs  upon  the  fruits  of  Rhus  glabra  are  of  two  kinds. 
It  is  chiefly  in  the  larger  and  those  filled  with  a  crimson,  acid  sap 
that  contain  the  valuable  constituents  of  this  drug.  These  hairs 
vary  from  more  or  less  broadly  top-shaped  or  carrot-shaped,  to 
spatulate  and  are  also  sometimes  more  or  less  narrow  elliptical 
(Fig.  1,  g).  They  vary  from-  100  to  400  microns  in  length,  and  are 
marked  by  transverse  or  oblique  partition  walls  forming  a  3-  to 
9-celled  hair,  the  broader  hairs  having  usually  not  more  than  three 
cells.  When  viewed  under  the  microscope  the  cells  are  seen  to  hold 
a  pink  colored  or  a  dark  reddish-wine  colored  cell  sap,  and  in 
glycerin  mounts  it  is  not  unusual  to  find  one  or  more  crystals  in  the 
shape  of  small  rods.  In  among  these  hairs  are  numerous  glandular 
hairs  with  short  one-celled  stalks  and  multicellular  heads.  These 
hairs  are  globular  or  broadly  elliptical,  vary  from  45  to  75  microns 
in  length,  are  of  a  yellowish  or  reddish-brown  color  and  in  chloral 
hydrate  solution  there  separates  one  or  more  oily  globules  on  the 
outer  membrane. 
The  calyx  of  Rhus  glabra  shows  a  few  uncellular,  somewhat 
curved  non-glandular  hairs  from  50  to  125  microns  in  length,  each 
