^PteXrPi9i5m'}  Myricacece  of  Eastern  United  States.  397 
veloped  a  series  of  striking  and  complex  glandular  hairs  of  the  nature 
of  the  tubercular  emergences.  Each  is  a  knob-like  expansion  of  the 
fruit  wall  into  which  a  copious  prolongation  of  subjacent  mesocarp 
tissue  has  spread,  but  farther,  from  an  abundant  and  densely  anas- 
tomosing complex  of  vascular  bundles  that  ramify  through  the  outer 
half  of  the  maturing  mesocarp,  fine  vascular  diverticula,  composed  of 
two  or  three  spiral  tracheae,  along  with  delicate,  elongated,  seive-like 
elements,  pass  through  the  stalk  of  the  emergences  and  end  in  a 
slight  swelling  in  its  middle.  The  epidermis  at  this  time  is  compara- 
tively shallow  and  thin-walled,  while  from  the  junction  of  the  epi- 
dermis with  the  base  of  each  emergence  elongated  unicellular  hairs 
spring  which  form  a  basket-like  system  round  and  upon  which 
copious  wax  exudations  subsequently  become  aggregated. 
At  this  time  the  mesophyll  is  divisible  into  two  recognized  zones, 
viz,  an  outer  irregular  and  large-celled  region  consisting  of  about 
12  or  13  layers,  and  an  inner  smaller  and  more  round-celled  tissue  of 
more  numerous  layers.  Prolonged  into  the  former  from  the  point  of 
attachment  of  the  fruit  with  the  axis  is  a  vascular  tissue  that  on 
entering  the  outer  layer  ramifies  abundantly  and,  as  above  stated, 
gives  off  delicate  diverticula  to  the  different  emergences.  At  this  time 
only  slight  indication  is  observed  of  a  difference  in  cell  contents, 
between  the  outer  and  the  inner  zone.  The  endocarp  is  a  shallow 
and  delicate  layer  that  from  now  on  becomes  less  and  less  conspicuous. 
By  mid- June,  or  soon  thereafter,  striking  changes  begin  to  appear. 
The  epidermis,  as  well  as  the  mesophyll  cells  of  the  emergences  the 
general  epidermal  (epicarp)  cells  of  the  fruit  wall  and  the  outer 
zone  of  the  mesocarp  have  all  enlarged  steadily  and  become  filled  up 
with  an  abundant  secretion  which  assumes  a  bizarre  coloration  when 
stained  with  saf ranin  and  methyl  green.  Tints  varying  from  neutral 
gray  through  pink,  crimson,  crimson-green,  green-blue,  yellow,  and 
brown  are  all  present  in  distinct  but  neighboring  cells,  and,  though 
the  writer  has  as  yet  been  unable  to  apply  abundant  tests,  the  above 
coloration  suggests  the  formation  and  presence  already  of  the  pal- 
mitic myristic,  and  stearic  acids  already  tested  for  and  recorded  by 
pharmacists  and  synopsized  by  Chevalier. 
At  this  time  the  inner  layer  of  the  mesocarp  contracts  conspicu- 
ously with  the  last,  its  cells  remaining  small,  thin-walled,  rounded, 
and  its  cavities  filled  with  delicate  protoplasm.  A  further  stage  in 
the  maturation  of  the  fruits  is  noted  by  the  middle  or  latter  part  of 
July.   Each  knob-shaped  emergence  has  developed  around  itself  an 
