-Am.  Tour.  Pharm. 
October.  1919. 
} 
Triticum  Re  pens. 
6S7 
two  lacunae  and  the  yellowish  ring  of  sclerenchyma.  A  drop  of 
tincture  of  iodine  gives  a  black  color  with  the  white,,  starchy  surface. 
Hole  us  mollis. — The  ring  of  sclerenchyma  in  this  case  is  more 
or  less  hypodermal,  like  the  outer  ring  in  Triticum  re  pens.  It  is  at 
least  twice  as  broad,  and  encloses  some  vascular  bundles.  Small 
islands  of  parenchyma  occur  at  intervals  below  the  epidermis,  and 
rudimentary  stomata  are  present  outside  such  groups  of  cells 
(Fig.  3).    Each  of  the  scattered,  central,  vascular  bundles  has  a 
sclerenchymatous  sheath  one  or  two  cells  wide.  This  species  re- 
sembles dog  grass  in  the  oval  shape  of  its  section  and  in  the  hollow 
center,  but  it  can  readily  be  distinguished  by  the  absence  of  starch 
and  by  the  absence  of  any  ring  of  ground  tissue  outside  the  scleren- 
chyma. Inosite  or  some  other  nutritive  substance  occurs  in  the  outer 
part  of  the  rhizome  in  the  form  of  small,  white  grains,  which  do  not 
stain  blue  with  iodine.  The  cortex  is  three  or  four  cells  wide,  as  in 
Cynodon,  and  contains  no  small  vascular  bundles. 
Agrostis  nil  gar  is. — The  ring  of  sclerenchyma  forms  a  common 
sheath  to  the  vascular  bundles,  like  the  inner  ring  of  Triticum 
repens.  This  ring  completely  encloses  the  outer  scattered  bundles, 
and  other  bundles  occur  inside  the  ring,  each  with  a  sclerenchyma- 
tous sheath,  one  or  two  cells  wide.  The  section  may  show  no  hollow 
center,  or  some  disintegration  may  be  present,  giving  a  crack 
(Fig-.  4)  or  a  hollow  center. 
Fig. 
Hokus  mollis. 
Fig.  4.    Agrostis  vulgaris. 
