ig8 



BOTANICAL GAZETTE 



[march 



This phenomenon he was not able to explain fully. Other papers 

 to be noted are those by Werth and Ludwigs (26), Hoffman (16), 

 and Moreau (18). A considerable summary of recent cytological 

 work is presented by Ramsbottom (22) . 



From this work it appears that the duration of the binucleate 

 stage varies in different species of short cycle rusts, being brief, 

 extended, or intermediate. Fusions between cells initiate this 

 binucleate condition. Some life history problems, including the 



TABLE I 

 Host relationships of short cycle Uromyces 



v 



Host 



Liliaceae 



Erythronium . . 



Cassiaceae 



Bauhinia 



Bauhinia 



Fabaceae 

 Psoralea 



Euphorbiaceae 

 Chamaesyce \ 

 Tithymalus / * 



Primulaceae 

 Primula 



Myrsinaceae 

 Myrsines 



Carduaceae 



Solidago 



Anaphalis 



Rudbeckia. . . . 

 Bidens 



Species of 

 Uromyces 



U. heterodermus 



Distribution 



Rockies 



U. bauhiniicola 

 U. jamaicensis 



U. abbreviatus 



U. Tranzschelii 



U. nevadensis 



U. Myrsines 



U. Solidaginis 

 U. amoenus 

 U. Rudbeckiae 

 U. Bidentis 



S.W. Mexico 

 Mexico; West Indies 



Pacific Coast 



Western N.A 



Western N.A. 



Costa Rica; S.A. 



W.N. A.; Europe 



W r estern N.A. 

 Central N.A. 

 Porto Rico; S.A. 



Mycelium 



Local or rather diffuse 



Rather diffuse 

 Local 



Local, becoming 

 rather diffuse 



Diffuse 



Local or rather diffuse 



Common 

 condition of 

 germination 



Micro 



Micro 

 Micro 



Micro 



Micro 



Local 



Local 

 Local 

 Local 

 Local 



Micro 



Micro 



Micro 

 Micro 

 Lepto 

 Lepto 



Pycnia 



Present 



Present 

 Present 



Present 



Present 



Not known 



Not known 



Not known 

 Not known 

 Not known 

 Not known 



some 



relations in the formation of pycnia in 



forms, the 



determined 



mycelium 



Hosts 



The range of hosts attacked by these North American short 

 cycle species of Uromyces embraces both the monocotyledons and 

 dicotyledons. The situation is shown in table I. 



Foreign species of short cycle Uromyces fill in several families 

 not represented here. The wide range of hosts attacked indicates 

 that these rusts do not form a restricted group; one might expect 



