﻿272 
  BOTANICAL. 
  GAZETTE. 
  [ 
  OctobeFj 
  

  

  One 
  of 
  the 
  tissues 
  in 
  question 
  is 
  located 
  in 
  the 
  sieve 
  portion 
  of 
  the 
  vascu- 
  

   lar 
  bundles 
  of 
  the 
  stem, 
  the 
  pulvini, 
  the 
  petioles 
  and 
  the 
  veins. 
  The 
  cells 
  

   which 
  compose 
  it 
  are 
  very 
  like 
  the 
  sieve 
  cells, 
  but 
  larger, 
  with 
  more 
  or 
  

   less 
  oblique 
  end 
  walls 
  on 
  which 
  is 
  a 
  single 
  large 
  pit 
  whose 
  closing 
  mem- 
  

   brane 
  is 
  traversed 
  by 
  numerous 
  protoplasmic 
  threads. 
  The 
  contenta 
  of 
  

   these 
  cells 
  seems 
  to 
  be 
  a 
  glucoside 
  or 
  some 
  similar 
  body. 
  A 
  nucleus 
  is 
  

   always 
  present. 
  Another 
  part 
  of 
  the 
  system 
  consists 
  of 
  the 
  sensitive 
  

   parenchyma 
  of 
  the 
  pulvinus, 
  which 
  is 
  in 
  connection 
  with 
  the 
  conenchym» 
  

   which 
  surrounds 
  the 
  vascular 
  bundle. 
  There 
  is 
  no 
  direct 
  protoplasmic 
  

   connection 
  between 
  the 
  protoplasts 
  of 
  the 
  coUenchyma 
  and 
  those 
  of 
  the 
  

   conducting 
  tissue 
  of 
  the 
  bundle. 
  

  

  In 
  the 
  latter 
  part 
  of 
  the 
  work 
  the 
  author 
  discusses 
  the 
  physiology 
  of 
  

   the 
  sensitive 
  tissue 
  at 
  length. 
  So 
  close 
  and 
  continuous 
  is 
  his 
  discussion 
  

   that 
  it 
  is 
  not 
  possible 
  to 
  summarize 
  it 
  satisfactorily. 
  While 
  there 
  are 
  still 
  

   obscure 
  points 
  and 
  some 
  things 
  "hard 
  to 
  be 
  understood," 
  the 
  theory 
  is 
  

   certainly 
  more 
  satisfactory 
  and 
  open 
  to 
  fewer 
  objections 
  than 
  the 
  pres-. 
  

   ent 
  ones. 
  

  

  The 
  name 
  of 
  the 
  publisher, 
  Engelmann, 
  is 
  sufficient 
  guarantee 
  of 
  the 
  

   excellence 
  of 
  the 
  typography 
  and 
  beauty 
  of 
  the 
  plates. 
  

  

  Cretaceous 
  plants.^ 
  

  

  The 
  author 
  presents 
  here 
  a 
  preliminary 
  report 
  upon 
  a 
  collection 
  of 
  

   fossil 
  plants 
  made 
  by 
  himself 
  and 
  Prof. 
  Lester 
  F. 
  Ward 
  at 
  Martha's 
  Vine- 
  

   yard 
  during 
  the 
  summer 
  1889. 
  The 
  age 
  of 
  the 
  formation 
  in 
  which 
  these 
  

   fossils 
  occurred 
  has 
  finally 
  been 
  stated 
  to 
  be 
  Cretaceous, 
  and 
  probably 
  

  

  , 
  Middle-Cretaceous. 
  Seven 
  or 
  eight 
  species 
  are 
  enumerated 
  and 
  figured, 
  

   concerning 
  the 
  identification 
  of 
  which 
  a 
  few 
  remarks 
  may 
  be 
  made. 
  As 
  

   to 
  the 
  figured 
  leaves 
  of 
  Liriodendron, 
  it 
  is 
  rather 
  doubtful 
  whether 
  they 
  

   belong 
  to 
  this 
  genus 
  or 
  not. 
  They 
  agree 
  quite 
  well 
  with 
  figures 
  ot 
  

   similar 
  leaves 
  supposed 
  to 
  belong 
  to 
  this 
  genus, 
  given 
  by 
  other 
  authors, 
  

   but 
  It 
  seems 
  to 
  have 
  been 
  overlooked 
  that 
  this 
  form 
  of 
  leaf 
  is 
  more 
  char- 
  

   acteristic 
  of 
  quite 
  diflFerent 
  genera, 
  as 
  for 
  instance 
  Eucalyptus, 
  of 
  wbicj 
  

   several 
  species 
  show 
  the 
  same 
  shape 
  of 
  leaves. 
  They 
  have 
  been 
  iom 
  

   together 
  with 
  some 
  remains 
  of 
  undoubted 
  Eucalyptus, 
  and 
  this 
  circum 
  

   stance 
  seems 
  to 
  speak 
  in 
  favor 
  of 
  the 
  supposition 
  that 
  they 
  should 
  be 
  0°^ 
  

   to 
  this 
  genus. 
  The 
  author 
  has, 
  however, 
  figured 
  a 
  leaf 
  (fig-8 
  on 
  thepaw 
  

   which 
  he 
  has 
  identified 
  as 
  Eucalyptus, 
  but 
  it 
  is 
  very 
  poorly 
  preserved-J 
  

   hat 
  the 
  identification 
  is 
  not 
  without 
  question. 
  When 
  the 
  author';^ 
  

   fruit 
  of^ 
  Eucalyptus 
  «a 
  nut," 
  it 
  is 
  to 
  be 
  pointed 
  out 
  that 
  the 
  fruit 
  of 
  » 
  

   genus 
  ,8 
  a 
  capsule, 
  and 
  it 
  is 
  not 
  easy 
  to 
  understand 
  what 
  the 
  autho 
  

  

  . 
  ";^f 
  °' 
  ^y 
  ^^« 
  expression 
  " 
  nut 
  with 
  operculum 
  " 
  in 
  the 
  explanation 
  oi 
  

   P 
  ate 
  These 
  figured 
  remains, 
  supposed 
  to 
  belong 
  to 
  Eucalyptus, 
  are 
  n 
  

   fruits, 
  but 
  flowerbuds. 
  It 
  is 
  a 
  well-known 
  fact 
  that 
  the 
  calyx 
  m* 
  

   !!!ij!^!!!Ji^^%rtace^ 
  coherent 
  at 
  the 
  apex, 
  ^nd_tha^ 
  

  

  American'^Tr.'''^"";^" 
  Cretaceous 
  Plants 
  from 
  Martha's 
  Vineyard, 
  with 
  one 
  plate- 
  ( 
  

   American 
  Journal 
  of 
  Science. 
  Vol. 
  XXXIX. 
  1890.) 
  

  

  