188  Pipitzahoic  Acid  and  Species  of  Perezia.  j 
Am.  Jour.  Pharm. 
April,  1884. 
16.  Perezia  hebeclada,  PI.  Wright.    Acourtia  hebeclada,  D.  C. 
17.  Perezia  turbinata,  Llav.  et  Lex.  Valley  of  Mexico,  legit 
Schaffner. 
Species  of  Eastern  and  Southern  Mexico. 
18.  Perezia  oxylepis,  Gr.  Proceed.  Am.  Acad.,  xv.  Puebla "? 
Liebman. 
19.  Perezia  carpholepis,  Gr.  Acourtia  carpholepis,  Schultz  Bip. 
Liebman. 
20.  Perezia  Dugesii,  Gray.  Proc.  Am.  Acad.,  xix.,  Guanaxuato 
Duges  leg.  Acourtia  spec.  Plant.  Botteriana.  1172.  Orizava.  Botteri, 
Mohr  legit  1857. 
21.  Perezia  moschata,  Llav.  et  Lex.    Chiapas,  Giesbrecht. 
22.  Perezia  reticulata,  Gr.  Proustia  reticulata,  Lag.  Dumerilia 
reticulata,  Don.    From  the  Valley  of  Mexico  to  Oaxaca,  Galeotti. 
23.  Perezia  fruticosa  Llav.  et  Lex.    A  dubious  species. 
24.  Perezia  nudicaulis,  Gray.  Plant.  Wright.  Republic  Guate- 
mala, Skinner. 
Of  the  species  occurring  in  the  United  States,  the  writer  has  obtained 
specimens  of  two  species,  Perezia  nana  and  Perezia  Wrightii,  for 
which  he  is  indebted  to  the  kindness  of  Messrs.  Lemmon  and 
Pringle,  zealous  botanists  who  have  spent  the  past  season  in  the  botani- 
cal exploration  of  Arizona  and  Southern  California.  The  roots  attached 
to  several  specimens  furnished  sufficient  material  to  establish  the  pres- 
ence of  pipitzahoic  acid,  and  the  specimens  of  great  perfection  served 
as  originals  for  the  accompanying  illustrations  of  these  most  interesting 
plants. 
Perezia  nana  Gr.,  of  slender  growth  from  4  to  8  inches  high,  with  a 
slender,  creeping  or  ascending  root-stock,  articulated  mostly,  and  the 
joints  and  head  of  which  are  covered  with  tufts  of  fine  woolly  hairs. 
The  slender  wiry  stem  is  simple  or  sparsely  branched  from  the  base, 
slightly  flexuous,  angled  and  a  little  rough.  The  rigid,  coriaceous  leaves 
are  shining,  glandular,  scabrous,  strongly  reticulate  veined,  roundish 
ovate,  If  to  2  inches  wide  and  but  little  longer,  spinose  toothed, 
sessile  by  a  cordate  base  or  amplexicaul.  The  large  capitula  are 
terminal,  subsessile,  20-30  flowered  with  a  campanulate  involucre  of 
mucronate  cuspidate,  ciliated  scales,  arranged  in  three  rows,  of  which 
the  exterior  ones  are  ovate  and  the  interior  lanceolate,  all  purplish 
