228 
CoUinsonia  Canadensis. 
J  Am.  Jbur.  Pharm. 
t      May,  1885. 
pleura  consists  of  one  layer  of  cells,  the  walls  of  which  are  somewhat 
thickened.  The  testa  consists  of  two  layers,  the  inner  is  composed  of 
about  three  rows  of  cells  with  thickened  walls  (Figs.  17  and  18),  and 
the  outer  layer  is  made  up  of  a  single  row  of  cells.  The  cell  walls  of 
the  outer  layer  of  the  testa  are  very  much  thickened  and  extend  in  a 
radial  direction.  The  exterior  view  of  the  testa  shows  the  cell  walls  as 
wavy  lines.  The  external  layer  of  the  testa  is  yellowish,  while  the 
interior  one  is  brown. 
COLLINSONIA  CANADENSIS,  Linne. 
Natural  order,  Labiatoe. 
By  Charles  Napier  Lochman,  Ph.G. 
From  an  Inaugural  Essay. 
The  thick,  hard,  knotty  rhizome,  from  which  the  plant  undoubtedly 
received  the  names  stone-root  and  knot-root,  grows  horizontally  but  a 
few  inches  beneath  the  surface  of  the  soil  and  attains  a  length  of  about 
six  or  eight  inches.  The  plant  seems  to  delight  in  stony  soil,  as  it  is 
always  found  in  mountainous  or  very  rocky  and  shady  situations.  At, 
and  after  the  time  of  flowering,  the  leaves  have  an  agreeable  lemon-like 
odor,  due  to  volatile  oil  contained  in  glands  on  the  under-surface. 
About  the  time  that  the  fruit  is  mature,  especially  if  the  plant  is  so 
situated  as  to  be  in  the  direct  sunlight  for  part  of  the  day,  the  calices 
have  an  odor  similar  to  that  of  caraway;  whether  this  is  due  to  a 
volatile  oil  or  a  resin  I  haye  not  been  able  to  ascertain. 
Description. — Flowers  in  racemes,  arranged  in  a  terminal  panicle. 
The  calices  and  pedicels  covered  with  stalked  glands.  Calyx  some- 
what bilabiate,  becoming  four-sided  and  much  enlarged  in  fruit ;  upper 
lip  with  three  sharp-pointed  teeth,  lower  with  two  lanceolate  lobes ; 
hairy  in  the  throat.  Corolla  light  yellow,  generally  purple-veined  and 
hairy  on  the  inside,  elongated,  widening  from  the  throat  outwards; 
four  upper  lobes  small  and  obtuse ;  lower  lobe  much  larger,  ligulate 
and  beautifully  laciniate  fringed.  Fertile  stamens  two  (with  rudi- 
ments of  a  second  pair),  exserted,  much  exceeding  the  corolla.  Style, 
purple,  two  cleft  at  the  apex,  about  the  length  of  the  fertile  stamens. 
Ovary  deeply  four  parted,  usually  ripening  only  two  of  the  four  nut- 
lets. Stem  simple,  erect,  smooth,  glaucous,  obtusely  four  angled ;  from 
two  to  five  feet  high.  Leav^es  thin,  smooth,  light  green  above  (some- 
what darker  in  the  dried  state),  whitish  underneath,  ovate,  coarsely 
