I 



CULTURES QF UREDINE& IN i8gg [1900 



species of Euphorbia is not genetically related to the brown rust 

 equally abundant upon the same hosts. The evidence I have to 

 offer is not conclusive, but, so far as it goes, must change this 

 view. On June 20 aecidiospores from Euphorbia nutans were 

 sown upon two plants of the same species and upon one plant of 

 Euphorbia maculata. Nine days afterward uredo appeared upon 

 one of the plants of Euphorbia nutans, and in eleven days upon 

 the other, followed in both cases by teleutospores after a time, 

 the exact date not recorded, but the plant of E. maculata showed 

 no infection. 



Instead of speculating upon such meager data, I am inclined 

 to believe that Uromyces EuphorbicB is an autcecious species, and 

 to await further cultures showing if it is separable into races. 



5. Phragmidium speciosum Fr. 



The intimate association of a caeoma, which is not distinguish- 

 able from Caoma miniata Schl., with this exclusively American 

 species of Phragmidium, would have been accepted as sufficient 

 evidence of its genetic connection, if the same form apparently 

 had not been considered in Europe as the first stage of the very 

 different Phragmidium mucronaUim, a species that is also common 

 in this country. 



At the time when the teleutospores of Phr. speciosum were in 

 germinating condition no potted plants of native roses were avail- 

 able, and sowings were made upon the leaves of a tea rose, the 

 Kaiserin Augusta Victoria. The work was done by my assistant, 

 Mr. William Stuart, and the dates are not at hand, but in due course 

 of time many pustules of caeoma appeared. These bore every 

 resemblance to the usual form, although they did not become very 

 large, which may have been due to the host not being congenial. 



It is probably safe to assume that the rose caeoma in this 

 country belongs wholly to Phragmidium speciosum, or else that 

 there are two species not at present separable. 



6. Triphragmium Ulmariae (Schum.) Lk. 

 This species of rust, not heretofore reported for America, so 

 far as the writer knows, was found in considerable abundance 



