438  Structure  of  Our  Cherry  Barks.  {^imbJiwS1, 
what  glossy  green  on  the  upper,  and  much  lighter  green  on  the 
lower  surface. 
The  flowers  occur  in  late  spring,  after  the  leaves,  in  simple 
racemes  at  the  ends  of  small  leafy  branches.  They  are  small,  white 
and  with  a  decided  but  not  very  agreeable  odor.  The  drupes  are 
small,  round,  about  the  size  of  peas,  blackish-purple,  destitute  of  a 
Fig.  3. — Sclerenchyma  from  bark  of  Primus  serotina. 
bloom,  bitterish,  but  not  decidedly  astringent  to  the  taste,  and  con- 
taining  a  roundish-ovate,  marginless  pit. 
Structurally  the  barks  of  the  different  species  of  cherries  exam- 
ined resemble  one  another  in  the  following  particulars  : 
(1)  The  phellogen  begins  its  formation  in  the  first  layer  of  col- 
lenchyma  cells  beneath  the  epidermis,  and  no  considerable  develop- 
ment of  the  phelloderm  layer  beneath  takes  place. 
