﻿468 
  Arthur: 
  New 
  species 
  of 
  Uredixeae 
  

  

  r 
  

  

  Idaho, 
  Oregon, 
  Washington, 
  West 
  Virginia, 
  Virginia; 
  Alberta, 
  

   British 
  Columbia; 
  Guatemala. 
  

  

  I 
  am 
  indebted 
  to 
  Mr. 
  Ivar 
  Jorstad, 
  plant 
  pathologist 
  to 
  the 
  

   government 
  of 
  Norway, 
  for 
  calling 
  my 
  attention 
  to 
  the 
  misappli- 
  

   cation 
  of 
  the 
  name 
  Melampsora 
  arctica. 
  While 
  in 
  this 
  country 
  

   in 
  1919-20 
  he 
  paid 
  two 
  visits 
  to 
  Purdue 
  University, 
  and 
  made 
  

   most 
  helpful 
  suggestions 
  regarding 
  the 
  synonymy 
  and 
  limitation 
  

   of 
  a 
  number 
  of 
  species 
  to 
  appear 
  soon 
  in 
  the 
  North 
  American 
  

   Flora. 
  He 
  pointed 
  out 
  that 
  no 
  rust 
  was 
  known 
  in 
  Europe 
  corre- 
  

   sponding 
  to 
  the 
  American 
  caeoma 
  on 
  Abies, 
  

  

  Mr. 
  Jorstad 
  further 
  directed 
  attention 
  to 
  the 
  essential 
  identity 
  

   of 
  Melampsora 
  alpinajnel 
  and 
  M. 
  arctica 
  Rostr., 
  as 
  given 
  in 
  the 
  

  

  7 
  th 
  

  

  Ame 
  

  

  confirmed 
  by 
  his 
  own 
  studies. 
  In 
  Greenland, 
  where 
  Rostrup's 
  

   material 
  was 
  obtained, 
  various 
  species 
  of 
  Saxifraga^ 
  on 
  which 
  the 
  

   aecia 
  are 
  to 
  be 
  looked 
  for, 
  are 
  common, 
  while 
  species 
  of 
  Abies 
  are 
  

  

  1 
  

  

  absent. 
  In 
  Europe 
  M. 
  alpina 
  Juel 
  has 
  been 
  cultured 
  by 
  means 
  of 
  

   Saxifraga 
  caeoma 
  on 
  Salix 
  herbacea, 
  the 
  common 
  American 
  host 
  

   recorded 
  for 
  M. 
  arctica. 
  M. 
  arctica 
  is 
  the 
  older 
  name, 
  and 
  the 
  

   species 
  to 
  which 
  it 
  properly 
  applies 
  is 
  a 
  boreal 
  form 
  with 
  aecia 
  on 
  

   Saxifragaceae, 
  and 
  entirely 
  distinct 
  from 
  the 
  more 
  southern 
  

   M. 
  americana 
  with 
  aeripi 
  on 
  A 
  hips. 
  

  

  Pucciniastrum 
  americanum 
  (Pari.) 
  comb. 
  nov. 
  

  

  Pucciniastnim 
  arcticiim 
  americanum 
  Pari. 
  Rhodora 
  10: 
  16. 
  1908. 
  

  

  This 
  species 
  differs 
  from 
  Pucciniastrum 
  arcticum 
  (Lagerh.) 
  

   Tranz., 
  with 
  which 
  it 
  has 
  been 
  united, 
  especially 
  by 
  the 
  narrow, 
  

   urceolate 
  peridium, 
  which 
  is 
  readily 
  distinguished 
  from 
  the 
  broad, 
  

   low 
  peridium 
  of 
  P. 
  arcticum, 
  even 
  under 
  a 
  low 
  power 
  of 
  the 
  micro- 
  

   scope. 
  P. 
  arcticum 
  is 
  a 
  boreal 
  species, 
  chiefly 
  known 
  from 
  northern 
  

   Europe 
  and 
  Alaska. 
  In 
  Alaska 
  it 
  occurs 
  on 
  Rubus 
  stellatus 
  

   Smith 
  and 
  R. 
  Chamaemonis 
  L. 
  Outside 
  of 
  Alaska 
  only 
  two 
  

   American 
  collections 
  are 
  known, 
  one 
  on 
  R. 
  pubescens 
  Raf. 
  (P. 
  

   triflortis 
  Richards.), 
  from 
  Grand 
  Manan, 
  New 
  Brunswick, 
  August, 
  

   1888, 
  K, 
  Miyabe, 
  and 
  one 
  on 
  P. 
  occidentalis 
  L., 
  from 
  Algona, 
  

   Wisconsin, 
  September, 
  1914, 
  B, 
  O, 
  Dodge. 
  

  

  P. 
  americanum 
  is 
  more 
  southern 
  and 
  a 
  much 
  more 
  abundant 
  

   species. 
  It 
  ranges 
  through 
  the 
  southern 
  part 
  of 
  Canada 
  from 
  

  

  