468 
Book  Reviews. 
Am.  Jour.  Pharm. 
June,  1918. 
upon  heterogeneous  material,  partly  since  new  and  undescribed 
species  in  herbaria  were  confused  with  the  commonly  known  species 
and,  further,  because  of  the  surprisingly  small  number  of  any  one 
species  collected  heretofore  in  a  given  region,  accountable  to  the 
contempt  with  which  common  weeds  such  as  Xanthium  are  often 
regarded. 
The  writers  made  a  detailed  study  of  5  specimens  of  this  genus, 
four  of  which  were  found  in  the  herbarium  of  the  Field  Museum 
and  a  fifth  in  that  of  the  Missouri  Botanical  Garden.  They  com- 
pared these  with  Xanthium  americanum  (which  has  for  its  fruiting 
involucre  a  bur  distinctly  ovoid  in  shape,  1.2-1.5  cm.  long  (exclu- 
sive of  the  beaks),  the  beaks  straight  or  nearly  so,  and  the  entire 
body,  aside  from  its  prickles,  more  or  less  glabrous ;  the  prickles 
straight  from  base  almost  to  apex  where  they  are  usually  hooked) 
and,  finding  the  specimens  so  different  from  any  form  of  Xanthium 
known  to  them,  describe  these  as  new  species. 
Xanthium  leptocarpum  Millsp.  &  Sherff  has  fruiting  involucres 
which  are  reddish-brown  or  chestnut  colored  and  are  narrowly 
cylindric-fusiform,  not  ovoid.  The  prickles  are  very  few  in  number 
and  noticeably  far  apart. 
Xanthium  arcuatum  Millsp.  &  Sherff  has  burs  more  or  less  of 
a  reddish-purple  shade,  but  the  prickles  are  very  numerous  and 
mainly  flexed  or  arcuate  from  the  base  to  the  apical  hook. 
Xanthium  cylindricum  Millsp.  &  Sherff  has  leaves  much  like 
those  met  with  on  Hibiscus  militaris  Cav.  The  burs  have  a  body 
distinctly  cylindrical,  not  ovoid,  and  the  beaks  are  curved. 
Xanthium  crassifolium  Millsp.  &  Sherff  has  subdeltoid,  3-  or  5- 
lobed  leaves  and  narrowly  cylindrical-fusiform  echinate  burs. 
Xanthium  acutilobum  Millsp.  &  Sherff  has  fruiting  involucres  re- 
sembling Xanthium  crassifolium,  differing  from  it  in  its  subhastate, 
triangular,  thinner  and  much  larger  leaves  and  in  the  characters  of 
the  akene. 
An  excellent  taxonomic  description  is  given  of  a  new  species  of 
Solid  ago  which  the  same  authors  name  Solidago  emarginata.  This 
species  has  its  lower  leaves  cuneate-oblanceolate  in  outline  and  dis- 
tinctly notched  at  the  apex.  Its  inflorescence  suggests  6\  speciosa 
var.  angustata  T.  &  G.  (S.  rigidiuscula  Porter)  but  its  leaves  do  not 
possess  the  pronounced  reticulations  that  are  so  characteristic  of 
those  of  the  latter  species.    Plates  showing  the  principal  characters 
