Pl.  IV.    Economic  Botany.    Monographic  Installation  North  American  Forest 
Trees. 
The  elements  comprising  each  of  the  monographs  in  the  series  are:  A  glazed 
and  framed  tray  containing  a  branch,  flowers  and  fruits  and  a  block  of  wood  from 
the  same  tree  ;  a  photograph  of  the  tree  in  summer,  and  the  same  tree  in  winter, 
both  from  the  same  point  of  view  ;  a  seven-foot  trunk  and  transverse  section  ;  a 
commercial  plank,  a  two-foot  map  of  North  America,  colored  to  show  the  distri- 
bution of  the  species,  and  a  series  of  ornamental  cabinet  specimens  of  the  wood. 
