THE  AMERICAN 
JOURNAL  OF  PHARMACY 
FEBRUARY,  igoy. 
THE  INTERNAL  STRUCTURE  OF  THE  STEM  AND  LEAF 
OF  RUELLIA  CILIOSA  PURSH.,  PHLOX  OVAtA  L. 
AND  SPIGELIA  MARILANDICA  L. 
By  Theo.  Hoi,m. 
(With  two  plates.) 
In  a  previously  published  paper1  we  have  seen  that  the  roots  and 
rhizomes  of  these  plants  may  be  readily  distinguished  by  means  of 
their  structure,  and  especially  by  the  internal.  *  In  regard  to  the 
vegetative  organs  above  ground,  the  stem  and  leaf,  these  show,  also, 
a  very  characteristic  structure,  which  is  very  useful  to  the  separation 
of  these  plants,  when  the  determination  seems  doubtful. 
When  the  flowers  are  present  the  plants  are  easily  recognized  ;  in 
Spigelia  the  flowers  are  scarlet  outside,  yellow  within,  and  the  clavate 
tube  of  the  corolla  is  much  longer  (about  four  times)  than  the  lobes  ; 
in  Ruellia  the  flower  is  light  blue,  or  very  slightly  purplish,  with  a 
funnelform  corolla,  while  in  Phlox  the  corolla  is  pink  and  strictly 
salverform.  The  outline  of  the  foliage  is,  also,  very  distinct,  besides 
the  venation.  Our  Fig.  i  shows  the  stem-leaf  of  Spigelia;  Fig. 
2,  that  of  Ruellia  ;  Figs,  j  and  ^,  a  basal  and  a  stem-leaf  of  PJilox. 
Characteristic  of  the  leaf  of  Spigelia  is  that  most  of  the  lateral 
nerves  proceed  from  near  the  base  of  the  blade,  while  in  Ruellia  the 
blade  is  strictly  penninerved,  and  in  Phlox  ovata  the  lateral  nerves 
are  not  at  all  visible  in  the  stem-leaf  [Fig.  and  only  faintly  visible 
in  the  basal.  The  leaves  are  hairy  in  all  of  these  plants,  but  the 
hairs  are  very  small  in  Phlox  and  Spigelia,  and  hardly  to  be  detected 
by  the  naked  eye  ;  in  Ruellia,  on  the  other  hand,  the  lower  face  of 
1  This  Journal,  Vol.  78,  1906,  page  553. 
(5i) 
