^pteSrfw™  }      Rhus  Glabra  and  Rhus  Typhina.  407 
by  the  action  of  the  free  malic  acid  present.  As  a  matter  of  fact 
this  is  true  practically  of  all  plant  color  substances  as  I  11  have  shown 
in  an  article  on  "  The  Origin  and  Nature  of  Color  in  Plants."  An 
interesting  observation  is  that  of  Palen 17  who  reported  that  the 
coloring  principle  in  the  leaves  of  Rhus  glabra  seemed  to  resemble 
that  in  quercitron  bark,  meaning  thereby  probably  the  bark  of  the 
black  oak  (Quercus  velutina,  Lam.).  Perkin  and  Allen16  isolated 
the  coloring  matter  in  Sicilian  sumac  (Rhus  coriaricc)  and  found 
it  to  be  identical  with  myricetin,  the  coloring  matter  of  Myrica  nagi, 
and  are  of  the  opinion  that  the  different  species  of  Rhus  do  not 
contain  either  quercetin  or  quercitrin.  It  will  thus  be  seen  that  there 
are  many  interesting  phases  of  study  of  the  several  species  of  Rhus, 
the  fruits  of  which  are  clothed  with  acid  crimson  hairs.  Some 
additional  comparative  work  in  which  the  fruits  of  Rhus  copallina 
L.  were  used,  will  be  reported  upon  later, 
REFERENCES  TO  LITERATURE. 
I  Henry  Kraemer,  Amer.  J  our:  Pharm.,  82,  1910,  p.  51;  85,  1913,  pi. 
2Alphonse  Wood,  Class  Book  of  Botany. 
3  Charles  S.  Sargent,  The  Silva  of  North  America,  vol.  3,  p.  16. 
4  Asa  Gray,  Manual  of  Botany  of  the  Northern  United  States,  6th  ed.,  1890,  p. 
118. 
0  Benjamin  L.  Robinson  and  M.  L.  Fernald,  A  Handbook  of  the  Flowering 
Plants  and  Ferns,  1908,  p.  552. 
6  A.  Engler,  Anacardiacese  in  Engler  and  Prantl's  "  Die  naturlichen  Pflanzen- 
familien,"  p.  168. 
7  Nathaniel  Lord  Britton,  Bulletin  Torrey  Botanical  Club,  18,  1891,  p.  269. 
8 1.  Cozzens  in  Annals  of  the  Lyceum  of  New  York,  referred  to  by  W.  B. 
Rogers  in  Amer.  Jour.  Pharm.,  7,  1835,  p.  56. 
9  William  B.  Rogers,  Amer.  Jour.  Pharm.,  7,  1835,  pp.  56-62. 
10  William  J.  Watson,  Amer.  Jour.  Pharm.,  25,  1853,  pp.  193-198. 
""Henry  K.  Bowman,  Amer.  Jour.  Pharm.,  41,  1869,  p.  195. 
12  John  Stenhouse,  Amer.  Jour.  Pharm.,  34,  1862,  p.  253. 
13  Henry  Trimble,  Amer.  Jour.  Pharm.,  72,  1900,  p.  337;  Ibid.  75.  1903,  p.  344. 
14  Henry  Trimble,  Amer.  Jour.  Pharm.,  62.  .1890,  p.  564. 
13  G.  B.  Frankforter  and  A.  W.  Martin,  Amer.  Jour  Pharm.,  76,  1904,  pp.  151- 
158. 
16  Henry  Kraemer,  Proc.  Amer.  Philosoph.  Soc.,  xliii,  1904,  No.  177,  pp.  257- 
277. 
II  Joseph  A.  Palen,  Amer.  Jour.  Pharm.,  60.  1888,  p.  389. 
18  Perkin  and  Allen,  Proc.  Chem.  Society,  1896.  p.  157  abstracted  in  Amer.  Jour. 
Pharm.,  68,  1896,  p.  687. 
