AmAprn;iP892arm-}  Polygala  Alba.  181 
It  is  not  stated  in  Prof.  Lloyd's  paper  whether  his  specimens 
were  accompanied  by  roots ;  but  it  is  mentioned  that  all  these 
plants were  much  smaller  than  the  Pol.  Senega  gathered  in  Ken- 
tucky, and  that  the  North  Dakota  plants  grow  only  to  the  height 
of  5  to  7  inches,  and  have  only  small  roots.  Heretofore  I  have 
quoted  from  the  floras  of  the  Northern  United  States,  the  Southern 
United  States  and  the  Rocky  Mountain  Region,  showing  that  the 
plant  attains  a  height  of  12  inches.  Still  as  the  height  of  the  stem 
is  no  indication  of  the  dimensions  of  the  root,  the  information  kindly 
given  by  Dr.  Vasey  applies  more  directly  to  the  question  at  issue. 
In  my  paper  of  Septb.,  1889,  I  give  the  diameter  of  the  root  for  the 
portion  beneath  the  head,  i.  e.x  immediately  beneath  the  stem  rem- 
nants, while  Dr.  Vasey's  measurement,  as  given  above,  obviously 
applies  to  the  body  of  the  root.  Comparing  the  measurements  we 
have : 
Length  of  root :  30  cm.  (Dr.  V.);  4  to  6  inches  —  20  —  30  cm. 
(M).  ' 
Diameter:  5  mm.  (Dr.  V.)\  %  inch  =  6  mm,  few  roots  (in  the 
commercial  article)  y%  inch  =  3  mm.,  some  ^  inch  —  9  mm.,  rarely 
y2  inch  =  12  mm.  (M).    These  figures  speak  for  themselves. 
Referring  to  the  fact  that  P.  alba  does  either  not  grow,  or  is  very 
scarce,  in  the  districts  where  senega  is  collected,  Prof.  Lloyd  sug- 
gests that  "  possibly  it  is  more  frequent  in  the  arid  plains  of  Ari- 
zona, New  Mexico  and  in  Mexico,  but  from  all  appearances  even 
there  only  in  limited  tracts."  This  suggestion  is  corrected  by  Dr. 
Vasey's  answer ;  and  as  a  supplement  to  it  may  be  quoted  Prof.  J. 
M.  Coulter's  Manual  of  the  Plants  of  Western  Texas,  where  TV.  alba 
is  reported  to  grow  in  " sandy  soil  throughout  Texas;  apparently 
the  most  common  Polygala." 
While  in  my  opinion  the  facts  presented  above  fully  sustain  my 
position  in  regard  to  the  origin  of  white  or  false  senega,  additional 
and  I  think  even  stronger  evidence  of  its  origin  from  a  species  dif- 
fering from  Pol.  Senega,  is  to  be  found  in  the  structure  of  the  two 
roots,  as  I  pointed  out  in  1877,  described  briefly  in  188 1,  and  illus- 
trated in  the  National  Dispensatory  and  in  my  Manual  of  Organic 
Materia  Medica  by  sketches  drawn  from  sections  of  the  two  roots. 
These  differences  may  be  briefly  summed  up  as  follows :  The  root 
of  Pol.  alba  shows  upon  transverse  section  a  circular  wood  sur- 
rounded by  a  bark  of  uniform  thickness,  the  thin  layer  of  the  inner 
