444 
Structure  of  Our  Cherry  Barks. 
/  Am.  Jour.  Pharm. 
(  September,  1695. 
The  sclerenchymatous  elements  are  less  abundant  than  in  Prunus 
serotina,  and  consist  mostly  of  small  clusters  of  bast  fibres,  stone- 
cells  being  wholly  or  nearly  absent.  The  medullary  rays  are  quite 
similar  to  those  of  P.  serotina,  and  the  intervening  sieve  elements 
are,  in  the  -older  bast  areas,  likewise  much  crushed  and  fissured. 
Fig.  9. — Sclerenchyma  fibres  from  Prunus  Avium  as  they  appeared  in  situ  in  a 
longitudinal  section. 
Crystals  of  calcium  oxalate  are  abundant,  but  much  less  so  than  in 
P.  serotina,  and  are  seldom  single  in  the  cells,  but  in  stellate  clusters. 
Probably  owing  to  the  season  of  the  year  when  the  bark  was 
gathered,  namely,  in  June,  no  starch  grains  were  recognized. 
