152       •  Ballota  Hirsuta.  { Am^™%  ^%m' 
The  glandular  trichomes  have  either  a  one-  to  two-celled  short 
or  long  stalk  and  a  one-,  two-  or  eight-celled  balloon-shaped  glandu- 
lar head.  The  large  number  of  the  last  mentioned  (balloon)  type 
which  possess  unicellular  short  stalks  is  very  striking  (Figs.  4 
and  5). 
Sections  made  through  the  calyx  show  to  a  modified  degree  the 
peculiar  microscopic  structure  of  the  foliage  leaf.  The  lamina  is 
thinner  and  more  trichomes  of  the  glandular  variety  are  evident. 
Ballota  hirsuta  Bentham. 
Ballota  hirsuta  Benth.  is  a  perennial  hirsute  herb,  which  is  in 
digenous  to  Mediterranean  countries.  The  herbarium  specimen  ex- 
amined (Fig.  2)  presented  the  following  macroscopic  perculiarities : 
Stem  quadrangular,  pubescent  but  not  white-woolly  like  Marrubium. 
Leaves,  opposite,  petiolate,  ovate  to  orbicular,  coarsely  hairy  on 
upper  surface,  coarsely  whitish-woolly  on  under  surface,  apex  obtuse, 
base  sub-cordate,  margin  crenate,  venation  pinnate-reticulate.  Inflor- 
escence a  verticillaster,  the  hermaphrodite  flowers  appearing  in  dense 
axillary  clusters  and  usually  fewer  in  number  than  in  the  verticil- 
lasters  of  Marrubium.  Each  flower  consists  of  a  bilabiate  infun- 
dibuliform  calyx,  up  to  10  Mm.  long  (Fig.  3,  B)  with  limb  showing 
a  margin  of  10  broadly  acute  or  mucronate  teeth,  a  distinctly 
bilabiate  .corolla,  four  included  stamens,  and  a  bi-carpellary  pistil. 
The  fruit  consists  of  four  nutlets. 
Microscopical  Characteristics  of  Ballota  hirsuta  Benth. 
Transverse  sections  (Fig.  7)  made  through  the  lamina  region  of 
the  foliage  leaf  show  typical  dorsoventral  structure.  Passing  from 
ventral  to  dorsal  surface  the  following  structures  present  them- 
selves for  examination : 
Upper  epidermis,  devoid  of  stomata  and  composed  of  tabular 
cells  with  outer  walls  more  or  less  convex  and  showing  a  rather 
thick  cuticle.  Directly  beneath  this  tissue  is  a  layer  of  somewhat 
loosely  arranged  vertically  elongated  palisade  cells,  the  average 
being  shorter  than  those  found  in  Marrubium  vulgar e.  Beneath 
the  palisade  layer  are  several  layers  of  more  or  less  loosely  arranged 
spongy  parenchyma  cells,  irregular  in  shape.  Through  this  region 
course  numerous  collateral  fibro-vascular  bundles  marking  the  posi- 
tions of  the  veins.    The  tracheae  of  these  have  strongly  lignified 
