Cinchona  pitayensis.    x  40.  Cinchona  lancifolia.    x  40. 
Resin-cells  absent. 
Laticiferous  ducts  present  (in  young  bark).  C.calisaya:  Thickest 
fibres  observed  average  mm.  -095  in  diameter.   Fibres  mostly  separate. 
Laticiferous  ducts  present  (sometimes  obscured  in  old  bark  (C. 
succirubra;  thickest  fibres  average  mm.  -085  in  diameter.  Fibres  ia 
lines,  and  occasionally  groups  of  2  to  8. 
Laticiferous  ducts  present  (soon  obliterated).  (C.  officinalis.) 
^The  key  here  given  differs  only  slightly  from  that  of  the  National  Dispensatory 
or  of  Berg's  Atlas,  but  the  writer  has  included  no  statements  which  he  has  not  veri- 
fied, and  has  been  able  to  make  a  few  additions. 
