61 



Peronospora. 



47. Peronospora Schleideni linger, Syll. VIP", Fisch. IV■'^^ Lag- 

 skimmel (R 02 a '"« 6. 04 a "). 



May— August, common in the gardens. 



Allium cepa. S. Landbohejskolens Have; Falst. Stubbekabing (^/s 76 R 81 a^'). 

 Allium ascalonicum. F. Faaborg (R 87 f) ; S. Landbohajskolens Have, Haslev ! , 

 Koldemosegaard, 0rsl£iv (P. N.). 



48. Peronospora urticae (Lib.) de By., Syll. VII 2", Fisch. IV "^ 

 Naeldeskimmel (R 04 a "). 



June— August. 



Urtica urens Laesa!, J. St. Vildmose (^''/e 83), Bering near Aarhus (Jak. Lge); 

 Lang. Carlseje. 



49. Peronospora rumicis Cda., Syll. VII ^«^ Fisch. IV ■'"', Syre- 

 skimmel (R 02 a 2"), Skraeppeskimmel (R 04 a"), Lit: R 85 a. 



May— August. The mycelium is perennial in the subterraneous parts 

 of the host-plant. 



Rum^ex acefosa common f. inst. : J. St. Vildmose, Skive!, F. Klingstrup, Skaa- 

 rup C^/e 73); Lang. Carlseje; S. Rorvig, Lyngby Mose (F. K. R.). Rumex ace- 

 tosella. F. Vejstrup Aaskov. Rumex auriculafus. J. Dybdal, Bygholm! F. Ringe!, 

 Nyborg, Kirkeby. 



50. Peronospora polygon! Thiim., Fisch. IV '"\ Pileurtskimmel 

 (R 04 a "). 



May— Sept., quite common. Saccardo (Syll. VII ^^^) will unite this " 

 species with Peronospora farinosa. 



Polygonum aviculare. J. Aalborg (F. K. R.), Skive!; F. Skaarup CVe 78); S. 

 Saborg. Polygonum convolvulus. F. Ryslinge ! ; S. Ruderhegn ! . 



51. Peronospora alsinearum Caspary, Syll. VII ^''^ Fisch. IV "^^ 

 Fladstjerneskimmel (R04a"). 



It is common in May and June; may, however, be found even 

 from March till October. Its mycelium is perennial in the host-plant. 

 The form on Ammodenia has several times been considered as a spe- 

 cial variety: "form, halianthi" Eriks. (in Fungi parasitici scand. exsicc. 

 No. 96. 1883) and "var. honckenyae" Sydow (in Hedwigia 1900 p. 124, 

 Syll. XVI ^'^), in his herbarium Rostrup also calls it "Per. halianthi". 

 Concerning its fecundation see Ruhland (03). 



Cerastium semidecandrum. F. Broholm, Skovmallen ved Skaarup, Bjerne- 

 mose. Cerastium caespitosum. J. St. Vildmose, Skive!; F. Egeskov, Holmdrup, 

 Tiselholt; S. Tisvilde, Ledreborg (^^/s 72 C. Thomsen). Cerastium arvense. S. 

 Frederikssund!. Ammodenia peploides. J. Nykabing (C. H. O.), Skive!; F. Hals, 

 Nyborg (Joh. Lge), Stokkebaek Strand O^/t 77), Magaard; F. Bate. Stellaria 

 holostea. J. Sevel!. Stellaria nemorum. J. Skanderborg. Stellaria media very 



