138 DIMORPHISM IN FUNGl. 



says it is so rare that he has never met with it. The advocates of 

 hetercecism have, however, been claiming fresh discoveries since 

 this controversy, and apparently very distinct fungi, growing on 

 most opposite matrices, are now suggested to be related to one 

 another. Thus, a Coleosporivm found on Senecio vulgaris is sup- 

 posed to be one stage of Peridermium Pint, and so on with many 

 others. 



In the Quarterly Journal of Microscopical Science iox 1885, Mr. 

 Plowright has a further series of observations on the " Life 

 History of Certain British Heteroecismal Uredines," in which he 

 details the results of three years' experiments. Many of these 

 experiments are simply repetitions of what have already been tried 

 on the continent, which he undertook for the purpose of verifica- 

 tion, but some are quite new. The Ranunculus family are 

 peculiarly liable to be affected with yEcidiu7n, no less than eleven 

 species having yEcidia more or less frequently upon them, while 

 only four have Uromyces, or Uredospores, affecting them. It is 

 shown that in one case— viz., the Aicidiuni on Ranunculus ficaria — 

 the connection is not with the Uromyces occurring in this same 

 plant, but with one affecting the various Poa, especially P. tri- 

 vialis and P. pratensis. This same yEcidium is also found affecting 

 R. repens, and also produces its Uromyces in P. trivialis and P. 

 pratensis. But in this same R. repens occurs another yEcidium, 

 very much like the former, but which is connected with quite a 

 different fungus — viz., Puccinia magnusiana — the Uredospores of 

 which are found on the common reed, Phrag/nitis communis. In 

 1S83, Mr. Plowright found a long, straight ditch, full of reeds, 

 which for about twenty yards at both ends were completely black- 

 ened by P. magnusiaria, those in the middle being quite free. In 

 the spring of 1884, he, from time to time, carefully examined the 

 Rumices and Raminculi growing on both banks, feeling quite sure 

 he should find the ALcidium at both ends, but not in the central 

 part, and eventually he proved right, for at both ends of the ditch 

 he found R. repens abundantly affected with yEcidia, while in the 

 centre they were quite free. The Rumices remained free altoge- 

 ther. He had previously experimented with the spores of these 

 fungi, and so been led to the surmise, which was thus proved 

 correct. 



