14 



Mycologia 



The Car ex rusts (having aecia on Ribes are yet imperfectly 

 known. My own culture work began in 1901, and owing to the 

 remarkably pale aecia produced, the form in hand at the time 

 was named Puccinia albiperidia. Since then many cultures have 

 been made, and the status of the species has received considerable 

 attention, but not until recently has any well miarked morpho- 

 logical characters been discovered. Present studies indicate that 

 P. albiperidia is a species worthy of being maintained. Beside 

 the more or less pale aecia it possesses one basal pore in the 

 urediniospore. 



It is curious to note that the only other species of monocotyle- 

 donous rust known with a single basal pore in the urediniospore, 

 Uromyces uniporulus Kern, is also on Carex. When published 

 it had only been found in Connecticut on C. tenuis. Since then 

 it has been detected in Wisconsin on C. gracillima. These are 

 also the hosts of P. albiperidia, together with C. pallescens and 

 C. pubesceiis. Comparing the spores, it appears that the uredinio- 

 spores of the Puccinia and of the Uromyces not only agree in 

 the pore characters, but also as to form, size and color, i. e., in all 

 morphological characters. The teliospores are also alike except 

 in number of cells, and in the consequent length. If the sori of 

 the Puccinia often contained many one-celled teliospores, and 

 the sori of the Uromyces often had a few two-celled spores, U. 

 uniporulus might be considered a mere mesoporic form of P. 

 albiperidia. But such does not appear to be the case. However, 

 while in the present state of uredinological taxonomy the two 

 forms are to be maintained as distinct species belonging to dif- 

 ferent genera, yet U. uniporulus is doubtless only a morpho- 

 logical race of P. albiperidia. Cultures of P. albiperidia were 

 made in 1901, 1903 and 1904.^^ No cultures have yet been made 

 of U. uniporulus, but it probably has aecia on Ribes. 



The far more common and widely distributed species, for 

 which I am making the namQ Pttccinia Grossulariae serve, has 

 more deeply colored aecia and three equatorial pores in the 

 urediniospore. I am inclined to think that this is the common 

 gooseberry-Car^.r rust of this country and Europe, but I am not 

 able at present to define its limits, neither can I say whether the 



See Jour. Myc. 8 : 53. 1902 ; 10 : 11. 1904; and in part 11 : 58. 1905. 



