North American Species of Puccinia on Carex 219 



The discovery of such an unusual pore arrangement in a Uro- 

 myces on a sedge led to a search for urediniospores with this type 

 of pore location in a Puccinia. They were found in connection 

 with Puccinia forms on the two hosts mentioned and also on C. 

 pub esc ens and C. pallescens all of which are hosts for the Ribes 

 rust. The urediniospores which have previously been supposed 

 to belong with the telia known to infect Ribes possessed three 

 equatorial pores. The discovery of the new pore arrangement 

 even on specimens which had been used for successful cultures 

 suggested that two species must be intermixed. At first the 

 tendency was toward a belief that here might exist two species 

 both with aecia on Ribes, the usual one with three equatorial 

 pores and bright colored aecia widespread in both Europe and 

 America, and a less common but perhaps valid one with the single 

 basal pore and pale aecia. Nothing could have been more natural 

 than the suspicion that a structural character in the uredinial 

 stage had now been discovered to accompany the somewhat un- 

 certain character of the aecial stage and that Puc. albiperidia 

 was entitled to specific standing. The constant presence of 

 urediniospores with the three equatorial pores in all culture ma- 

 terial used for successful inoculations on Ribes finally led to the 

 conclusion that the telial stage of which they were a part could 

 account for the cultures, that Puc. albiperidia and Puc. Grossulariac 

 must after all be synonymous. This view left the form with 

 the basal pore unnamed and unconnected. About this time C. R. 

 Orton in making a study of correlations in the genera Puccinia 

 and Uromyces reviewed the matter, decided the i-pored form was 

 a valid species correlated with Uromyces uniporulus and supplied 

 the name Puccinia uniporula (Mycologia 4:201, 1912). Then 

 began definite steps to learn more of its standing through cultures. 

 It is very difficult to secure specimens in which all of the uredi- 

 niospores have a single basal pore but in 1915 Arthur reports 

 (Mycologia 8: 130, 1916) that material which may be considered 

 representatives of pure Puc. uniporula produced infection on 

 Ribes giving aecia identical with those grown previously from 

 material possessing three equatorial pores. There seems to be 

 such a remarkable association of the two types of urediniospores 

 in material capable of producing infection on Ribes that the pos- 



