FUNGI— THEIR NATURE AND HABITS. 3 



grow from a delicate mycelium. When these germinate they produce others, 

 and so on to the fifth generation in some cases. 



The Bean rust — Puccinia Fabae — has, besides male organs, four different 

 kinds of reproductive organs, only one of which reproduces the original form, 

 while all the others have undoubted alternation of generation. First, the puccinia 

 appears from the spores of which the ^cidium is produced and this is followed 

 in the regular course of generation by Uredo, the spores of which enter the leaves 

 of the bean and are developed into the Puccinia, thus completing the cycle of 

 transformations. 



It has been shown by Professor Henslow that Uredo linearis is only a second- 

 ary form of Puccinia graminis, thus proving that rust is but an earlier form of 

 mildew. It is also a question whether Uredo segetum and Uredo mayidis, the 

 smut of wheat and corn, are not only incomplete forms of other fungi. The na- 

 tural history of Puccinia graminis is a very interesting one. For a long time 

 farmers had believed that there was some mysterious relation between the Bar- 

 berry rust, ^cidium herberidis, and the Puccinia graminis, or wheat rust. This 

 was sneered at by those claiming superior wisdom, as a superstition similar to 

 the once popular notion that the moon exerted a controlling influence over ter- 

 restrial vegetation. But late investigations by men of eminence as naturalists, 

 and of superior ability as investigators, have proved this theory to be correct. 

 It has been observed that cereals growing in the vicinity of barberry bushes af- 

 fected with the ^cidium, became affected with rust as soon as the ^cidium had 

 completed its fructification and shed its spores. That the bushes were the origin 

 of the Puccinia in the wheat was rendered probable by the fact that the preva- 

 lence of the disease in the grain is seen to be in exact proportion to the contiguity 

 of this to the diseased bushes — the disease being largely developed in the grain 

 growing near the bushes but diminishing on receding from them, till at a consid- 

 erable distance it disappears altogether. But we are not left to inference in this 

 matter even from such positive premises, for M. DeBarry proved by direct exper- 

 iment that the Puccinia could be transplanted to the leaves of the Barberry, where 

 it produced the ^cidium, the spores of which when transferred to some member 

 of the family Graminese, again produces the Puccinia. That this is a very usual 

 mode of transformation in these two forms of fungi, is established beyond ques- 

 tion ; but that this is the only method of procedure, as recently asserted by an 

 Indiana professor is evidently not correct, for it has been proven that the spores 

 of the Puccinia may germinate directly on plants of the grass family. 



On any other hypothesis it would be impossible to account for the sudden 

 appearance of the wheat rust over wide regions of country, destroying the grow- 

 ing wheat by thousands of acres, as has been observed by the writer, where 

 there was probably not a Barberry bush, on an average, to each township. Some 

 other means must have been employed for the propagation and dissemination of 

 these multitudinous reproductive germs to cause such wide-spread devastation 

 of the growing grain as has, at times, been witnessed in some parts of the 

 country. 



