J. W. REED ON UROMYCES PISI. 67 



Fungi. It was not recognised that the -^cidium was only a 

 stage, or a special form of fructification, in the life-cycle of 

 particular groups of Fungi. But this condition of things, known 

 as Metcecism or Heteroecism — the former was the term used by 

 De Bary, the discoverer — is now a well-known fact, firmly 

 established by the sure method of questioning Nature herself by 

 careful and prolonged observation and experiment. This method, 

 as applied to the Fungi referred to, is happily neither expensive 

 nor difficult. 



There is a much dreaded Fungus, and the best known species 

 of the Uredinese, called Puccinia graminis — the mildew of wheat 

 — which appears to have been the first Uredine whose cyclic 

 development was noted. Mr. Massee, of the Koyal Herbarium, 

 Kew, in his " Evolution of Plant Life, Lower Forms," selects this 

 species as a typical one, and there describes its life- history. For 

 some time prior to a scientific inquiry into the matter, it had 

 been widely and strongly suspected, by quite unscientific people, 

 that with regard to the spread of Paccinia graminis there was a 

 mysterious connection between it and the proximity of Barberry 

 bushes. 



Quite recently a friend noticed at the railway station at 

 Thorney, in Cambridgeshire, some barberries infected with ^cidia, 

 further observation showing a band of discoloration extending 

 from these bushes right across an adjoining wheat-field. The 

 area of discoloration corresponded in width with the space occupied 

 by the diseased shrubs, and marked the track of innumerable 

 wind-borne spores. Similar phenomena, although their philo- 

 sophy was unknown, must have been frequently observed by 

 agriculturists in the past ; hence their mistrust. 



This suspicion took practical efiect in Massachusetts, more than 

 a century ago, by the passing of an Act known as the Barberry 

 Law, compelling, for the sake of agriculture, the destruction 

 of the barberry bushes. Part of the first clause reads thus : 

 — " Whoever, whether community or private person, hath any 

 Barberry Bushes standing or growing in his or their land, within 

 any of the towns in this Province, he or they shall cause the 

 same to be extirpated or destroyed on or before the thirteenth 

 day of June, Anno Domini One thousand seven hundred and 

 sixty." 



Farmers in England also believed that in some way the barberries 



