E. J. BUTLER 



51 



of a consignment of Continental grass seed had been sown. 



The parasite was found in the seed-coats of 5 per cent, of the 



seed that had produced a diseased crop and was clearly 



introduced in this manner.^ The Harper Adams Agricultural 



College has reported a case where a single consignment of 



potatoes from a crop infected with warty disease spread the 



disease over a district with a 5-mile radius. 



How far packings are responsible for carrying the spores of parasitic fungi 



is uncertain. Smut spores would no doubt travel readily in this way, but 



most of the destructive diseases of this class are already ^\^dely distributed 



and they would be carried still more easily as a rule on seeds. Soil is 



unquestionably dangerous, as many soil-dwelling parasites are long-lived and 



resistant to unfavourable conditions. But in a general way there does not 



seom to be sufficient evidence available to decide how far dry packings can 



serve as a means of transit for parasitic fungi. 



An analysis of some of the Australian rusts to show the probable means 

 of introduction of foreign species to a geographically isolated part of the world 

 may help to an estimation of the part played by man in disseminating 

 parasitic fungi by means of their transmission on plants or packings. 



In Australia, 90 species of Puccinia had been recorded up to 1905. Of 

 these 22 were considered by McAlpine (" Rusts of Australia," 

 Melbourne, 1906) to have been introduced. I have classified 

 them as follows : — 



Thirteen are on cultivated agricultural or horticultural plants, 

 presumably introduced by settlers, gardeners or the trade. 



P. Chrysanthemi on chrysanthemum. 



P. Cichorii on chicory. 



P. graminis "j 



P, triticina !- on wheat and barley. 



P. simplex J 



P. Helianthi on sunflower. 



P. Lolii on rye giass. 



P. malvacearum on hollyhocks, etc. 



P. Maydis on maize. 



P. Menthce on penny-royal. 



P. Primi on peaches, plums, etc. 



' Massee, G. Ki^w Bulletin, 1913, p. 205. 



