Oct. IS, 1921 Aecial Stage of the Orange Leaf rust of Wheat 



157 



them on as large a number of species as was done in 19 19, and attention 

 was devoted mainly to sowing upon species of Thalictrum. Of the 51 

 collections used 9 were sown upon as many Thalictrum species as possi- 

 ble in order to determine the relative susceptibility of these species. 

 The results are given in Table II. 



Tabl:^ II. — Data obtained in ig20 from sowing teliospores of Piiccinia triticina from 

 nine different localities on -various species of ThalictrumO' 



a — Noinfection, ■ . v, u'.vr^'! •,>'.t>.-.i, T 



Pycnia only produced. 



1 Aecia following pycnia. 



A numeral in parenthesis following the sign indicates the number of times the results were obtained. 

 ^ Although aecia were produced, the infection was weak. 



The following is a list of the sources of the telial material used in the 

 cultures : 



5619, from Athens, Ga., collected by C. A. Ludwig. 



6019, from W. Raleigh, N. C, collected by Ludwig and Wolf. 



7219, from Hickory, N. C, collected by C. A. Ludwig. 



7819, from Tennessee, collected by C. A. Ludwig. 



8019, from Coldwater, Mich., collected by B. W. Mains. 



8719, from Canton, Miss., collected by C. A. Ludwig. 



11619, from State College, Pa., collected by J. T. Adams. 



12519, from Moscow, Idaho, collected by C. W. Hungerford. 



15 1 19, from Reno, Nev., collected by G. R. Hoemer. 

 In addition to the sowings indicated in Table II, culture 8719 was 

 sown upon Aquilegia glandulosa F'isch., A. olympica Boiss., Clematis 

 heraclaefoHa DC, C. paniculaia Thunb., C. recta L., and Ranunculus acris 

 L-, all without infection. 



An examination of Table II shows that 12 out of the 14 species of 

 Thalictrum were infected, Thalictrum occidentale and T. aquilegifolium 

 apparantly being immune. The species on which infection occurred 

 showed varying degrees of susceptibility. Thalictrum dasycarpum and 



