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barley plants. Barley plants growing in the midst of rusted 

 wheat at the Sibpur Farm were found entirely free from rust, 

 but barley is also subject to a rust. 



M 



FIG. 75. PUCCINIA GRAMINIS. 



[ (a) Large oval sori in clumps on a blade of wheat, (b) One uredospore 

 detached from its clinode or stalk (x 300). (c 1 ) A germinating uredospore. (d) 

 Smaller, detached and round sori of Puccinia graminis var. rubigo-vera (e) 

 A detached rubigo-vera uredospore (X 300). (/) Two teleutospores attached 

 to their clinodes. (g) Promycelial growth from the two sections of a teleuto- 

 spore, showing also sporidia borne on short stalks.] 



1,370. The fungus was first noticed by Fontana an Italian 

 botanist in 1767, but its biology was first studied by the great 

 German botanist, de Bary. De Bary discovered that the 

 fungus has three distinct stages, (i) the uredo or the orange 

 colour stage, (2) the teleuto, or the black colour stage, and 

 (3) the aecidial stage. De Bary also discovered that the 

 aecidial stage of the fungus was passed in a different host 

 plant altogether, such as the bramble, the barberry, or the 

 borage, and not in the cereal plant affected. Dr. Prain dis- 

 covered, at the Sibpur Farm, all the three stages of the fungus 

 on a common weed belonging to the order Compositae locally 

 known as tikchond (Launea asplenifolia\ The absence of the 

 teleuto-stage in the wheat-rust at Sibpur may be accounted 

 for, according to the same authority, by its presence in the 

 tikchond. The connection between wheat-rust and the 

 Puccinia fungus found on tikchond has not however been 



