﻿Haynes: 
  Six 
  species 
  of 
  Riccia 
  285 
  

  

  very 
  

  

  so 
  closely 
  over 
  one 
  another 
  as 
  to 
  be 
  separated 
  with 
  difficulty, 
  the 
  

   upper 
  ones, 
  by 
  their 
  numerous 
  long 
  rootlets, 
  knitting 
  firmiy 
  to 
  

   the 
  pitted 
  surface 
  of 
  those 
  immediately 
  beneath 
  them. 
  The 
  

   lobes 
  are 
  crenate 
  and 
  obtuse, 
  not 
  emarginate, 
  extremely 
  thin 
  and 
  

   hyaline. 
  Spores 
  firmly 
  united 
  in 
  fours 
  into 
  a 
  sort 
  of 
  coccus 
  

   which 
  is 
  deeply 
  4-lobed, 
  and 
  

   more 
  deeply 
  lobed 
  than 
  in 
  Sphaerocarpiis 
  terrestris 
  and 
  more 
  

   finely 
  reticulated 
  and 
  papillose." 
  

  

  Type 
  locality: 
  North 
  Carolina. 
  

  

  Distribution: 
  North 
  Carolina 
  to 
  Florida 
  and 
  Texas. 
  

  

  Illustrations: 
  Bull. 
  Torrey 
  Club 
  43 
  : 
  pi. 
  4. 
  1916. 
  

  

  Exsiccatae: 
  Underw. 
  & 
  Cook, 
  Hep. 
  Am. 
  43 
  (as 
  Thallocarpus 
  

   Curtisii). 
  , 
  

  

  Appreciative 
  thanks 
  are 
  due 
  to 
  Dr. 
  Howe 
  and 
  Professor 
  Evans 
  

   for 
  valued 
  assistance, 
  to 
  the 
  Rev. 
  E. 
  E. 
  Brooks 
  for 
  a 
  translation, 
  

   and 
  to 
  Mr. 
  Severin 
  Rapp 
  for 
  specimens 
  of 
  R. 
  Donnellii 
  and 
  R. 
  

   Curtisii, 
  collected 
  at 
  different 
  periods 
  of 
  the 
  year. 
  

  

  Highlands, 
  ' 
  

  

  I 
  

  

  New 
  Jersey 
  

  

  Explanation 
  of 
  plates 
  10-13 
  

  

  Plate 
  io 
  

  

  Riccia 
  Donnellii 
  Aust. 
  

  

  Fig. 
  I, 
  Dorsal 
  side 
  of 
  an 
  unusually 
  large 
  mature 
  plant, 
  showing 
  several 
  cap- 
  

   sules; 
  in 
  older 
  parts, 
  walls 
  rupturing 
  and 
  spores 
  scattering; 
  hyaline 
  marginal 
  pappillae 
  

   plainly 
  Visible. 
  Drawn 
  from 
  dry 
  material. 
  X 
  4. 
  

  

  Fig. 
  2. 
  Ventral 
  side 
  of 
  a 
  thallus, 
  showing 
  beginnings 
  of 
  tuberiferous 
  or 
  resting 
  

   stage 
  not 
  uncommonly 
  met 
  with 
  in 
  collections 
  made 
  in 
  January 
  and 
  February. 
  

   Drawn 
  from 
  fresh 
  material. 
  X 
  4. 
  Austin's 
  original 
  description 
  mentions 
  this 
  

   tendency 
  to 
  thicken 
  ventrally 
  at 
  the 
  apex 
  of 
  the 
  axis, 
  which 
  is 
  "greatly 
  thickened 
  

   and 
  blunted 
  as 
  it 
  grows 
  downwards." 
  This 
  fact 
  has 
  been 
  lost 
  sight 
  of 
  in 
  more 
  

   recent 
  descriptions. 
  

  

  Fig. 
  3, 
  Portion 
  of 
  epidermis, 
  with 
  marginal 
  cilia. 
  X 
  47. 
  

  

  Fig. 
  4. 
  Dorsal 
  side 
  of 
  old 
  fruiting 
  plant, 
  through 
  the 
  transparent 
  wing 
  of 
  which 
  

   the 
  well-developed 
  stalked 
  tuber 
  is 
  seen 
  arising 
  from 
  the 
  ventral 
  apex 
  of 
  the 
  costa. 
  

  

  Fig. 
  5. 
  Unusually 
  well-developed 
  tuberous 
  prolongation 
  of 
  the 
  costa, 
  showing 
  

   rudimentary 
  scales. 
  X19. 
  

  

  Fig. 
  6. 
  Cross-section 
  near 
  apex 
  of 
  a 
  tuber. 
  X 
  9- 
  

  

  Fig. 
  7. 
  Outline 
  of 
  a 
  cross-section 
  of 
  thallus. 
  X 
  ip- 
  

  

  Fig. 
  8. 
  Portion 
  of 
  epidermal 
  layer, 
  in 
  cross- 
  sect 
  ion, 
  drawn 
  from 
  fresh 
  materia!. 
  

   X 
  120. 
  

  

  *See 
  McAllister, 
  F. 
  The 
  morphology 
  of 
  Thallocarpus 
  Curtisii. 
  Bull. 
  Torrey 
  

   Club 
  43: 
  117-126. 
  pL 
  4, 
  1916, 
  

  

  