Hctercecism. 5 5 



for although the above facts were in themselves unanswered, 

 yet the so-called scientific botanists urged that the fungus 

 upon the barberry leaves belonged to a totally distinct 

 genus (iEcidium) to that upon the wheat (Puccinia). There 

 is evidence to show that many careful observers, even at 

 this time, suspected that the Puccinia was connected in 

 some way with the uredospores which occur as its pre- 

 cursors. This remained a suspicion only until Tulasne 

 demonstrated that the connection between the uredospore 

 and the teleutospore existed not only in the species in 

 question, but was the general rule amongst the Uredineae. 

 In 1 86 1, De Bary showed that many of the Uredineae not 

 only had uredospores and teleutospores, but also that the 

 latter gave rise in many cases (but not in all) to aecidio- 

 spores, and conversely the secidiospores to uredospores. 



De Bary also pointed out that in certain cases the 

 sowing of germinating teleutospores upon the same species 

 of host-plant which bore them was not followed by any 

 result. Amongst these were Puccinia graininis. It further 

 occurred to him that, as there were several aecidia unac- 

 companied on their host-plants by any other spore-form, 

 these might belong to Uredines which passed a part of 

 their life upon one plant and the remainder upon another. 

 Familiar with the facts already known to the practical 

 agriculturist concerning the barberry and wheat mildew, 

 he put the matter to the test of actual experiment. In 

 1864, he sowed Puccinia graininis on barberry and produced 

 the ^cidium, and in 1865 he did the converse culture, by 

 sowing the aecidiospores upon rye. 



The results obtained by his experiments with P. 

 graminis led De Bary to investigate the life-histories of 

 other aecidia, which, like ^c. berberidis, are unaccompanied 

 by any other spore-form on the same host-plant. Thus he 

 found that P. rnbigo-vera has its aecidiospores upon Lycopsis 



