same  size  as  in  the  currant,  although  somewhat  narrower  and  more 
nearly  terete.  Unlike  the  European  gooseberry,  the  surface  is  free 
from  prickles. 
Histology. — Pericarp  (i)  The  Epicarp  and  (2)  Hypoderm  are 
practically  the  same  as  in  the  red  currant. 
(3)  Mesocarp. — This  layer  is  composed  of  extraordinarily  large 
cells  (often  0-5  millimeter  in  diameter),  which  are  evident  to  the 
naked  eye  and  are  separated  from  each  other  by  a  network  of  cells 
hardly  0  05  millimeter  in  diameter.  In  the  inner  layers  the  small 
cells  are  less  numerous  or  entirely  lacking.  Crystal  clusters  are 
abundant,  particularly  in  the  inner  layers. 
(4)  Endocarp. — The  most  striking  histological  distinction  between 
the  currant  and  the  gooseberry  is  in  the  structure  of  the  endocarp, 
Fig.  22. — American  Gooseberry  {Ribes  oxyacanthoid.es).  I  Whole  fruit,  X  1. 
II  Transverse  section  of  fruit  with  seeds,  X  .1.  Ill  Seeds  deprived  of  gela- 
tinous coat,  X  8. 
which  in  the  currant  is  a  dense  sclerenchymatous  tissue,  in  the 
gooseberry  a  layer  of  parenchyma  cells  with  walls  so  thin  that  they 
are  studied  with  difficulty.  This  remarkable  difference  in  structure 
of  two  fruits  of  the  same  genus  led  the  writer  to  examine  the  fruit 
of  R.  aureum,  the  only  other  species  of  this  genus  available  for 
study.  In  this  fruit,  which  resembles  more  the  black  currant  than 
the  gooseberry,  the  endocarp  cells,  although  apparently  parenchy- 
matous, had  thicker  walls  than  those  of  the  latter,  and  the  cells  were 
arranged  in  a  manner  similar  to  those  of  the  sclerenchymatized 
endocarp  of  the  currant.  A  study  of  this  coat  in  other  species,  and 
in  all  stages  of  development,  would  doubtless  disclose  other  inter- 
mediate forms. 
Testa,  Endosperm,  and  Embryo. — The  microscopic  structure  of  the 
seed  is  practically  the  same  as  that  of  the  currant  seed. 
