522     NOMENCLATURE,  ETC.,  IN  THE  MATERIA  MEDICA,  U.  S.  P. 
tracted  axis  and  a  fleshy  leaf.  If  this  is  admitted,  the  officinal 
portion  of  colchicum  and  arum  are  not  corms,  but  tubers. 
The  development  of  the  new  tubers  of  colchicum  takes  place 
in  early  summer  ;  the  short  underground  stem  flowers  late  in  the 
fall ;  its  leaves  are  developed  the  following  spring,  and  soon 
afterwards  its  lowest  internode  becomes  fleshy  and  thickened  and 
produces  the  succeeding  autumn  again  a  short  branch,  on  which 
the  flcgver  is  borne.    {Fluckiger  s  Pharmako gnosis,  181). 
The  same  process  requires  a  much  shorter  time  with  Arum 
triphyllum.  Immediately  after  the  flowering  period  in  the 
spring,  a  number  of  buds  are  produced  upon  the  tuber  which 
soon  develop  into  short  rhizomes  of  about  the  thickness  of  a  thin 
quill ;  the  last  (several  ?)  internode  then  begins  to  swell  and 
assume  a  depressed  globular  shape,  from  the  upper  half  of  Avhich 
adventitious  roots  are  formed,  when  the  rhizome  gradually  dies, 
leaving  the  newly  formed  tubers  separate,  and  the  apex  of  each 
with  the  rudimentary  bud  for  the  overground  stem  which  is  de- 
veloped the  succeeding  year.  A  few  weeks  after  flowering,  the 
short- lived  rhizomes  and  the  new  tubers  may,  in  rich  soil,  be  dug 
up  in  every  phase  of  development  and  decay. 
The  Pharmacopoeia  states  American  Senna  to  be  the  leaves  of 
Cassia  marilandica.  Though  placed  in  the  primary  list,  I  have 
been  unable  to  find  it  in  our  commerce  for  years  past ;  but  what 
I  did  see,  fifteen  and  more  years  ago,  consisted  correctly  of  the 
leaflets  only,  and  was  then  a  much  cleaner  drug  than  Alexandria 
senna. 
Though  never  found  in  our  commerce,  our  Pharmacopoeia  very 
properly  ordered  the  leaves  only  of  ISTepeta  cataria,  and  imposes 
upon  the  pharmacist  the  trouble  of  garbling  the  commercial 
article.  With  the  same  propriety  ought  to  have  been  directed, 
instead  of  the  herbs,  the  leaves  of  Mentha  piperita  and  viridis, 
Mellissa  officinalis,  Marrubium  vulgare,  Hedeoma  pulegioides 
and  probably  some  others. 
Instead  of  the  herb  and  flowers,  the  tops  and  leaves  ought  to 
be  directed  of  Achillea  millefolium,  as  is  very  properly  the  case 
of  absinthium  and  eupatorium,  though  both  are  usually  met  in 
our  commerce  intermixed  with  the  stems. 
Rosmarinus  is  defined  as  the  tops,  while  the  commercial 
article  consists  of  the  leaves  of  R.  officinalis. 
