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in Denmark; but during late years good works on the Uredinales of 

 some of our neighbouring countries have been published, and these 

 have been a great help to me in the preparation of the following 

 account; especially are to be pointed out: J. I. Liro: "Finlands Rost- 

 svampar" and F. Bubak: "Bohmens Rostpilze", both pubhshed in 

 1908, containing many independent descriptions of the species and 

 giving splendid contributions to their biology; E. Fischer's work on 

 the Uredineae of Switzerland and Klebahn's work on the heteroecious 

 Uredineae are also of great value as also Sydow: "Monographia 

 Uredinearum' which I quote as far as concerns all species of Puccinia 

 and Uromyces, those being the only genera up to date described in 

 this standard work; Saccardo's Sylloge, and Winter I are quite out of 

 date. 



For a comparison I shall state that up to this day 261 species of 

 Uredinales have been found in Denmark while in Finland 246 spe- 

 cies have been found, in Bavaria 312, in Tyrol 310 (Magnus 05 a), 

 in Switzerland 375 (Fischer 04); it must be noted that Switzerland 

 has 2400 vascular plant-species against the 1400 species of Denmark. 

 Of the Uredinales occuring in the neighbouring countries and which 

 we must suppose will, on closer investigation, also be found in this 

 country may be mentioned: 



Uredinopsis filicina (Aspidium phegopteris), Melampsorella Feuri- 

 chii (Asplenium septentrionale), Uromyces salicorniae (Salicornia 

 herbacea), Uromyces scrophulariae (S. nodosa), Urom. thapsi (Ver- 

 basc. thapsus), Urom. minor (Trifolium montanum), Puccinia galanthi, 

 Puce, actaeae-agropyri, Puce, astrantiae. Puce, vulpinae (Tanacetum &. 

 Carex vulpina) etc. 



The numerous splendid contributions which Danish mycologists 

 have made to our present knowledge of the biology of these fungi 

 are now only of historical interest, so I will here only give a brief 

 recapitulation of the most important of the discoveries particularly 

 concerning" the heteroecious Uredineae for which we have to thank 

 Danish mycologists and among these especially A. S. 0rsted, C. Gad, 

 E. Rostrup and P. Nielsen. 



A. S. 0rsted. 



In 1865 0rsted infected Pirus communis with teleutospores of Gym- 



nosporangium sabinae. 

 - 1866 — — Sorbus aucupariae with teleutospores of 



Gymnosporangium juniperinum. 

 1867 — — Crataegus oxyacantha with teleutospores of 



Gymnosporangium clavariiforme. 



