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



159 



Thalictrum polygamum Muhl. 19. Source: Ithaca, N. Y. Distribution: 

 Eastern United States. 



Thalictrum sp. (98). Source: Palisade Nursery Co. Distribution: 

 Exotic. 



Thalictrum sp. (55). Source: Farr Nursery Co. Distribution: Exotic. 



From the data presented above it is evident that a number of species 

 of Thalictrum are susceptible hosts for Puccinia triticina. As far as the 

 host determinations are at all certain, the evidence would indicate that 

 the most susceptible hosts are from western Asia and eastern Europe, 

 and doubtless in this region other species will be found of as great or 

 greater susceptibility. 



The remaining collections of telia showing good germination were 

 sown on one or more of the susceptible species of Thalictrum in order 

 to determine how uniformly Puccinia triticina from the United States 

 would go to Thalictrum. Table III gives the results of these cultures. 



Table III. — Data obtained in ig20 from sowing teliospores of Puccinia triticina, from 

 many different localities, on four especially susceptible species of Thalictrum o- 



Nmnber and source of telia. 



5119 Pa 



11719 Pa.. . . 

 9819 W. Va. 

 6319 N. C. . 

 6419 N. C. . 

 7319 N. C. . 

 5819S. C. ... 

 5019 Ga. . . . 

 4119 Ala. . . . 

 4519 Ala. . . . 

 4419 Tenn.^. 

 17419 Tenn. 

 6519 Ky . . . . 

 4819 Ind. . . . 

 5319 Ind.... 

 10119 Ind. . . 

 10419 111 . . . 

 12419 Minn. . 

 3619 Iowa. . 

 9219 Mo. . . . 

 9319 Mo . . . . 



9519 Mo 



9619 Mo . . . . 



3819 La 



6719 Tex. .. . 

 7019 Tex.c. . 

 3219 Ariz. . . 

 61 19 Calif. . 

 122 19 Wash. 

 165 19 Wash. 

 199 19 Wash. 

 I39i9 0reg. . 



T. sp. (ss). 



T Delavayi 

 <S6). 



T. flavum 

 (Si). 



T. sp. (98) 



I-(2) 



o — No infection. 



Pycnia produced. 



1 Aecia following pycnia. 



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

 *> Sown also on T. angustifolium, producing pycnia, and on T. aquilegifolium without results. 

 e Sown also on T. dasycarpum without results. 



