AMbJe°cCIi^87A2M  }  On  Officinal  Rhubarbs.  54  ' 
long,  covered  with  a  black  bark,  soft,  humid,  and  containing  a  yellow 
sap-wood.  These  characters  are  very  perceptible  in  a  plant  sent  by 
M.  Dabry  to  M.  Soubeiran,  in  the  putrified  mass  of  which  some  shoots 
were  found  still  intact  by  M.  L.  Neumann.  These  shoots  carefully 
cultivated  have  produced  some  plants,  one  of  which  has  flowered  with 
M.  Giraudeau,  in  the  valley  of  Montmorency,  and  another  is  culti- 
vated in  the  Garden  of  the  Faculty  of  Medicine  at  Paris.  It  has 
there  produced  leaves  of  about  a  metre  and  a  half  in  length,  and  of 
which  the  limb,  a  little  broader  than  long,  is  orbicular,  deeply  five- 
lobed,  and  incised,  cordate  at  the  base,  pale  green,  glabrous  above, 
densely  covered  underneath  by  a  fine  white  down,  which  does  not  al- 
ter the  green  tint.  In  the  inflorescence,  the  bracts  of  about  two  me- 
tres in  length,  ramified,  foliate,  and  bare  at  the  summit,  are  sur- 
mounted by  numerous  cymes  of  whitish  flowers,  remarkable  for  the 
depth  of  their  concave  receptacles  and  the  green  color  of  their  disks. 
The  aerial  portion  of  the  axis  of  this  plant,  for  which  the  name  of 
Rheum  officinale  is  proposed,  is  a  thick,  short,  ramified  stem,  whilst 
the  subterranean  portions  are  cylindrical,  of  small  size, — therefore  of 
little  practical  use, — -and  easily  destroyed,  from  which  cause  it  is 
rarely,  and  in  but  small  quantity,  imported  into  Europe.  This  is  the 
reverse  of  what  is  found  in  the  European  rhubarbs,  of  which  the 
fuller  developed  root  is  the  part  usually  employed,  together  with  a 
small  portion  of  the  stem.  But  in  the  Thibet  rhubarb  the  part  prin- 
cipally employed  is  the  aerial  stem  or  branches.  Hence  the  peculiar 
characters  of  this  drug  as  it  is  generally  met  with  in  commerce.  It 
is  characterized  by  its  color,  smell  and  taste — found  in  the  living 
plant  from  Thibet — and  by  the  numerous  starred  spots  which  are  ob- 
served in  sections  of  certain  portions.  The  pretended  black  bark 
which  is  removed  in  cleaning  this  rhubarb  is  nothing  but  a  mass  of 
leaf  bases  and  of  ochreas  which  cling  to  the  surface  of  the  stem.  As 
the  stems  of  Rheum  which  have  been  planted  in  France  comport 
themselves  as  true  sympods,  on  the  surface  of  which  there  are  not 
only  leaves,  but  also  axillary  buds,  it  is  not  astonishing  that  these 
buds,  separated  from  the  mother-plant,  readily  develope  adventitious 
roots,  allowing  of  their  easy  reproduction.  Thus  the  future  is  assured 
of  a  large  number  of  stalks  of  this  plant,  handsome  in  an  ornamen- 
tal point  of  view,  and  susceptible  of  being  successfully  cultivated  in 
France  in  the  open  air,  where  it  has  already  supported  a  winter  of 
20°. 
