﻿204 
  JOURNAL 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  8 
  

  

  cates 
  in 
  the 
  herbarium 
  of 
  the 
  CaHfornia 
  Academy 
  of 
  Sciences 
  and 
  the 
  U. 
  S. 
  

   National 
  Herbarium. 
  

  

  Gardner-near-Hood 
  Island, 
  on 
  which 
  this 
  species 
  is 
  found, 
  is 
  a 
  tiny 
  islet 
  

   only 
  2 
  km. 
  or 
  less 
  from 
  Hood 
  Island, 
  the 
  locality 
  of 
  A. 
  lecocarpoides 
  Robins. 
  

   & 
  Greenm. 
  The 
  two 
  forms 
  are 
  very 
  closely 
  related, 
  but 
  A. 
  brachyceratum 
  

   may 
  be 
  distinguished 
  by 
  its 
  much 
  smaller, 
  more 
  finely 
  lobed 
  leaves, 
  its 
  shorter 
  

   peduncles, 
  and 
  its 
  shorter-spined 
  fruit. 
  It 
  is 
  described 
  by 
  the 
  collector^ 
  as 
  a 
  

   common 
  bush 
  two 
  feet 
  high. 
  

  

  Acanthospermum 
  leptolobum 
  Blake, 
  sp. 
  nov. 
  Figure 
  1, 
  a, 
  d-j. 
  

  

  Annual, 
  dichotomous, 
  about 
  1 
  m. 
  high, 
  the 
  stem 
  and 
  branches 
  slender, 
  

   woody, 
  grayish, 
  densely 
  tuberculate-hispidulous 
  ; 
  leaves 
  opposite, 
  rather 
  

   densely 
  hispidulous 
  on 
  both 
  sides; 
  petioles 
  about 
  8 
  mm. 
  long, 
  connate 
  at 
  base, 
  

   narrowly 
  margined, 
  about 
  1 
  mm. 
  wide; 
  blades 
  ovate, 
  2.5 
  to 
  4 
  cm. 
  long, 
  1.3 
  

   to 
  4 
  cm. 
  wide, 
  pinnatifid 
  nearly 
  to 
  midrib, 
  the 
  leaf 
  rachis 
  1 
  to 
  2 
  mm. 
  

   wide, 
  the 
  lobes 
  about 
  5 
  pairs, 
  mostly 
  opposite, 
  irregularly 
  2 
  to 
  8-lobed 
  with 
  

   linear 
  obtuse 
  segments 
  or 
  the 
  uppermost 
  entire, 
  the 
  segments 
  again 
  sometimes 
  

   toothed; 
  peduncles 
  terminal, 
  solitary, 
  densely 
  spreading-hispidulous 
  with 
  

   subglandular 
  hairs, 
  1.3 
  to 
  2.5 
  cm. 
  long; 
  heads 
  about 
  3 
  cm. 
  wide; 
  phyllaries 
  4, 
  

   ovate, 
  obtuse 
  or 
  acute, 
  usually 
  serrulate, 
  hispidulous 
  chiefly 
  beneath, 
  8 
  to 
  

   10 
  mm. 
  long, 
  4.5 
  to 
  6 
  mm. 
  wide; 
  rays 
  10, 
  yellow, 
  oval, 
  tridenticulate, 
  merely 
  

   closed 
  in 
  a 
  ring 
  at 
  base 
  without 
  proper 
  tube, 
  about 
  9-nerved, 
  stipitate-glandu- 
  

   lar 
  dorsally, 
  10 
  mm. 
  long, 
  4.5 
  mm. 
  wide; 
  disk 
  corollas 
  numerous, 
  yellow, 
  the 
  

   slender 
  tube 
  sparsely 
  glandular, 
  1.5 
  mm. 
  long, 
  the 
  campanulate 
  throat 
  1 
  mm. 
  

   long, 
  the 
  five 
  recurved 
  triangular 
  teeth 
  1 
  mm. 
  long; 
  stamens 
  cordate-sagittate 
  

   at 
  base; 
  pales 
  acuminate, 
  lacerate-dentate 
  above, 
  stipitate-glandular, 
  about 
  

   3 
  mm. 
  long; 
  fruit 
  compressed-turbinate, 
  densely 
  stipitate-glandular 
  and 
  more 
  

   or 
  less 
  hispidulous, 
  whitish 
  at 
  maturity, 
  the 
  body 
  2.8 
  to 
  3.5 
  mm. 
  high, 
  2.2 
  

   to 
  3.5 
  mm. 
  deep 
  at 
  apex, 
  bearing 
  at 
  apex 
  1 
  to 
  5 
  horns, 
  the 
  1 
  to 
  3 
  inner 
  subulate 
  

   or 
  lance-subulate, 
  1 
  to 
  4 
  mm. 
  long, 
  divergent-spreading, 
  when 
  large 
  excavated 
  

   at 
  the 
  base, 
  or 
  sometimes 
  wanting, 
  the 
  1 
  to 
  3 
  outer 
  triangular 
  to 
  subulate, 
  erect 
  

   or 
  curved-ascending, 
  1 
  to 
  4 
  mm. 
  high, 
  at 
  least 
  the 
  central 
  one 
  excavated 
  at 
  

   base, 
  the 
  latter 
  sometimes 
  represented 
  only 
  by 
  its 
  deeply 
  excavated 
  base 
  and 
  

   without 
  free 
  portion, 
  or 
  all 
  the 
  horns 
  entirely 
  wanting. 
  

  

  Type 
  in 
  the 
  Gray 
  Herbarium, 
  collected 
  in 
  woodland 
  at 
  Sappho 
  Cove, 
  

   Chatham 
  Island, 
  Galapagos 
  Islands, 
  altitude 
  240 
  meters, 
  February 
  10, 
  1906, 
  

   by 
  Alban 
  Stewart 
  (no. 
  700). 
  Duplicates 
  in 
  the 
  herbarium 
  of 
  the 
  California 
  

   Academy 
  of 
  Sciences 
  and 
  the 
  U. 
  S. 
  National 
  Herbarium. 
  

  

  Chatham 
  Island, 
  on 
  which 
  this 
  species 
  occurs, 
  is 
  about 
  50 
  km. 
  from 
  Hood 
  

   Island. 
  Its 
  representative 
  of 
  Acanthospermum, 
  A. 
  leptolobum, 
  is 
  so 
  different 
  

   from 
  that 
  of 
  Hood 
  Island 
  that 
  its 
  specific 
  distinctness 
  is 
  likely 
  to 
  be 
  confirmed 
  

   by 
  future 
  collecting, 
  while 
  the 
  form 
  found 
  on 
  Gardner-near-Hood 
  Island, 
  

   A. 
  brachyceratum, 
  is 
  so 
  much 
  closer 
  to 
  A. 
  lecocarpoides 
  that 
  it 
  may 
  prove 
  to 
  be 
  

   only 
  a 
  variety. 
  Stewart*^ 
  describes 
  his 
  no. 
  700 
  as 
  a 
  common 
  bush, 
  3 
  to 
  4 
  ft. 
  

   high, 
  in 
  woodland 
  at 
  800 
  ft., 
  and 
  says: 
  "Except 
  for 
  the 
  presence 
  of 
  spines 
  on 
  

   the 
  achenes 
  [fruits] 
  the 
  specimens 
  from 
  this 
  island 
  are 
  more 
  like 
  Lecocarpus 
  

  

  5 
  A. 
  Stewart. 
  Botanical 
  survey 
  of 
  the 
  Galapagos 
  Islands. 
  Proc. 
  Calif. 
  Acad. 
  IV. 
  1: 
  148. 
  

   1911. 
  

  

  ^ 
  Loc. 
  cit. 
  

  

  