The Scottish Naturalist. 81 



than by British botanists ; and the theory of Hetercecism has been 

 far more widely adopted by the former than by the latter as the 

 best explanation of the facts, and as in harmony with the results 

 of experiment. 



But in 1 88 1 and 1882 Mr. C. B. Plowright has occupied him- 

 self with numerous experiments, with the view of corroborating or 

 disproving the statements and experiments of Continental mycolo- 

 gists ; and he has published the result of his experiments, and the 

 conclusions to which they have led him, in Grevillea, Vols. X. and 

 XI. These conclusions are in agreement in general with those 

 prevalent elsewhere, and embodied in Winter's "Die Pilze" in 

 Rabenhorst's " Kryptogamenflora," new Ed. In a subject of so 

 great interest, alike as a scientific and as a practical problem, and 

 one in regard to which the published records of experiments are 

 few in the English language, a somewhat detailed recapitu'ation of 

 Mr. Plowright's results may be given with advantage, and will, we 

 believe, be welcome to the readers of this magazine. 



His experiments in 1881 were conducted entirely on ALcidium 

 Berberidis and Pucci?iia graminis, with a view to convince himself 

 one way or the other in regard to the connection said to exist be- 

 tween these fungi. The result of the experiments of that year 

 was that in thirteen sets of experiments where seedling wheat- 

 plants were grown, and half of each set infected with pores of 

 sEc. Berberidis, while the other half were kept as far as possible 

 free from infection as check-plants, Uredo linearis developed itself 

 on the infected plants in twelve of the sets, but also upon the 

 check-plants in eleven of the sets ; and in consequence he was 

 hardly able to believe in proofs being obtained, sufficiently reliable, 

 of any genetic relationship such as had been asserted to exist. 



In 18S2, however, he continued his experiments in the same 

 direction, and extended them to other fungi of the same group, 

 alleged to show similar cycles, with the result that " overwhelming 

 evidence of the Hetercecismal nature of several species was forth- 

 coming." 



k ' In these cultures various and less common Uredines were em- 

 ployed, so that the error of accidental sporadic infection, it is 

 scarcely possible to believe, could have taken place, time after 

 time, with species after species. To take for instance the Roestelice. 

 On every occasion upon which I have infected hawthorns Avith 

 I-odisoma Juniperi, and pears with P. Sabince, the corresponding 

 Roestelice have been produced. Now both these Roestelice are very 

 uncommon plants near King's Lynn. With Gymnospora?iginm 

 upon mountain ash, four out of five cultures were successful, 

 which is the more noteworthy when it is remembered that the 

 Gyimwspora?igium was sent from Forres, in the north of Scotland 

 (^ome 400 miles away), by my friend the Rev. James Keith, it 

 being a plant that does not grow in this district. 



" All the cultures of Puccinia gra minis on Barberry were success- 



F 



