﻿510 
  REPOET 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  Root 
  hairs 
  have 
  been 
  found 
  on 
  the 
  following 
  plants: 
  ** 
  

  

  Elodea 
  canadensis 
  Michaux. 
  Philotria 
  canadensis 
  (Michaux) 
  Britton. 
  

  

  Naias 
  flexilis 
  Rostkovius 
  & 
  Schmidt. 
  

  

  Naias 
  flexilis 
  robustat 
  Morong. 
  

  

  Potamogeton 
  pectinatus 
  Linnteus. 
  Potamogeton 
  filiformis 
  Persoon. 
  

  

  Potamogeton 
  pauciflorus 
  Pursh. 
  Potamogeton 
  foliosus 
  Rafinesque. 
  

  

  Potamogeton 
  gramineus 
  Linnseus. 
  Potamogeton 
  heterophi/llus 
  Schreber. 
  

  

  Potamogeton 
  lucens 
  Linnaeus. 
  Potamogeton 
  lonchites 
  Tuckermaii. 
  Potamogeton 
  

  

  zizii 
  Roth. 
  

   Potamogeton 
  natans 
  Linnaeus. 
  

   Potamogeton 
  perfohatus 
  Linnaeus. 
  

   Potamogeton 
  praelongus 
  Wulfen. 
  

   Potamogeton 
  zosteraefolius 
  Schumacher. 
  

   Ranuncuhis 
  aquatilis 
  trichophyllus 
  Gray. 
  Batrachium, 
  trichophyllum 
  (Chaix) 
  

  

  Bossch. 
  

   Vallisneria 
  spiraUs 
  Linnaeus. 
  

  

  The 
  following- 
  do 
  not 
  develop 
  root 
  hairs, 
  but 
  are 
  well 
  provided 
  with 
  

   roots: 
  

  

  Bidens 
  beckii 
  Torrey. 
  

  

  Heteranthera 
  graminea 
  Vahl. 
  Heteranthera 
  dubia 
  ( 
  Jacquin) 
  MacMillan. 
  

  

  Myriophyllum 
  sparsiflorum 
  Wright. 
  Myriophyllum 
  spicatum 
  Linnaeus. 
  

  

  BEHAVIOR 
  OF 
  ROOTS 
  AS 
  ORGANS 
  OF 
  ABSORPTION. 
  

   ABSORPTION 
  OF 
  LITHIUM 
  NITRATE. 
  

  

  While 
  the 
  experiments 
  alread}' 
  described 
  render 
  the 
  absorption 
  of 
  

   mineral 
  salts 
  by 
  the 
  roots 
  highly 
  probable, 
  it 
  is 
  of 
  course 
  desirable 
  

   to 
  secure 
  more 
  direct 
  evidence. 
  For 
  this 
  purpose 
  two 
  methods 
  were 
  

   employed: 
  First, 
  a 
  1 
  per 
  cent 
  solution 
  of 
  lithium 
  nitrate 
  in 
  tap 
  water 
  

   was 
  offered 
  to 
  the 
  roots, 
  and 
  after 
  a 
  time 
  the 
  upper 
  parts 
  of 
  the 
  plant 
  

   were 
  tested 
  for 
  lithium 
  with 
  the 
  flame 
  and 
  spectroscope. 
  The 
  second 
  

   method 
  was 
  merely 
  a 
  direct 
  measurement 
  of 
  the 
  water 
  absorbed. 
  

  

  RANUNCULUS 
  AQUATILIS 
  TRICHOPHYLLUS. 
  

  

  Experiment 
  No. 
  14. 
  — 
  This 
  was 
  performed 
  in 
  the 
  greenhouse 
  on 
  February 
  7. 
  A 
  

   cutting 
  was 
  taken 
  from 
  the 
  stock 
  aquarium 
  and 
  allowed 
  to 
  grow 
  roots 
  which 
  were 
  

   straight, 
  unbranched, 
  intact, 
  and 
  clothed 
  with 
  hairs. 
  The 
  plant 
  ready 
  for 
  the 
  test 
  

   may 
  be 
  described 
  as 
  follows: 
  Distance 
  from 
  the 
  node 
  at 
  the 
  base 
  of 
  the 
  cutting 
  to 
  the 
  

   terminal 
  node, 
  20 
  cm. 
  ; 
  from 
  the 
  node 
  at 
  the 
  base 
  of 
  the 
  cutting 
  descended 
  one 
  root 
  

   20 
  cm. 
  in 
  length; 
  from 
  the 
  first 
  node 
  above 
  the 
  basal 
  node 
  of 
  the 
  cutting 
  descended 
  

   one 
  root 
  10 
  cm. 
  in 
  length. 
  

  

  As 
  the 
  test 
  must 
  be 
  made 
  with 
  the 
  plant 
  submerged, 
  it 
  is 
  very 
  necessary 
  that 
  none 
  

   of 
  the 
  lithium 
  nitrate 
  solution 
  escape 
  from 
  the 
  containing 
  bottle 
  into 
  the 
  surrounding 
  

   water. 
  To 
  separate 
  root 
  and 
  stem 
  an 
  adequate 
  stopper 
  was 
  made 
  by 
  saturating 
  

   cotton 
  in 
  melted 
  vaseline. 
  Such 
  a 
  stopper 
  can 
  be 
  wrapped 
  around 
  the 
  stem 
  until 
  it 
  

   snugly 
  tits 
  the 
  bottle. 
  The 
  vaseline 
  makes 
  it 
  water-tight 
  and 
  prevents 
  capillarity 
  

   along 
  the 
  stem, 
  yet 
  does 
  not 
  injure 
  the 
  plant. 
  

  

  «The 
  nomenclature 
  of 
  this 
  list 
  is 
  that 
  of 
  the 
  Index 
  Kewensis, 
  a 
  dagger 
  indicating 
  

   a 
  more 
  recently 
  established 
  species, 
  and 
  the 
  italicized 
  names 
  the 
  synonyms. 
  

  

  