236 
Larrea  Mexicana. 
Am.  Jour.  Pharm. 
May,  1898. 
It  is  called  by  the  Mexicans  Gobernadora  and  Hideondo,  and 
popularly  Creosote  Bush  and  Greasewood. 
The  habitat  of  the  plant  is  rather  an  extensive  one.  It  is  found 
abundantly  in  the  dry  valleys  of  Kern  County  and  in  the  Death 
Valley  of  Inyo  County,  California,  and  eastward  from  Walker's  Pass 
and  Talhichipi  to  Western  Texas,  and  southward  into  Mexico;  also 
along  the  lower  Muddy  River  in  Nevada  and  the  Santa  Clara  Val- 
ley of  Utah. 
The  plant  is  a  diffusely  branched,  densely  leafy  evergreen  shrub, 
4-10  feet  high.  The  leaves  and  small  twigs  are  thinly  spread  with 
a  covering  of  a  strongly-odorous  resin  that  closely  resembles  in 
appearance  ordinary  shellac.  To  the  abundance  of  this  resinous 
matter  the  plant's  popular  name  of  creosote  bush  is  due,  for  in 
burning  the  green  wood  and  leaves  a  pungent  odor  is  detected  and 
a  dense  smoke  arises.  The  dead  branches  remain  for  many  years 
without  decomposing,  and,  although  seldom  more  than  2  or  3  centi- 
meters in  diameter,  they  furnished  the  principal  fuel  to  the  Death 
Valley  Expedition. 
The  functions  of  the  resin  seem  to  be  to  lessen  transpiration,  and 
thus  to  adapt  the  plant  to  the  dry  localities  in  which  it  grows.  If 
this  coating  completely  covered  the  leaves  throughout  the  entire 
year,  all  evaporation  would  cease  and  the  death  of  the  plant  would 
ensue,  but  it  has  been  found  that  while  the  leaves  in  the  winter  time 
seem  thoroughly  varnished,  the  spring  growth  examined  in  June 
shows  very  little  coating.  As  many  of  the  herbarium  specimens 
are  gathered  at  this  season  of  the  year  during  the  flowering  period, 
they  seldom  show  the  resinous  coating  conspicuously,  as  it  has  not 
yet  developed. 
The  leaves  are  nearly  sessile ;  the  thick  resinous  leaflets  unequi- 
lateral,  oblong,  3-6  lines  long,  with  a  broad  attachment  of  the  mid- 
rib, somewhat  curved  and  acute.  The  flowers  are  solitary,  bright 
yellow,  consisting  of  five  ovate,  obtuse,  silky,  deciduous  sepals ;  five 
unguiculate  petals;  ten  stamens  on  a  small  ten-lobed  disk,  and  a 
five-celled  ovary,  the  cells  about  six  ovuled.  The  fruit  is  globose, 
two  and  a  half  lines  in  diameter,  densely  hairy,  consisting  of  five 
indehiscent  one-seeded  carpels,  which  at  length  separate  from  the 
axes. 
It  is  said  that  no  animal  of  the  country  will  eat  the  plant.  It  has 
various  reputed  properties.  Miners  say  that  a  strong  decoction  will 
