y6 



wholly on one host plant, altogether omit some of the 

 spore forms from the life stor}'. Whilst showincr these 

 variations, however, the rust fungi are all highly 

 specialised parasites ; they cannot grow apart from living 

 plants, and with rare exceptions, a specific rust fungus is 

 restricted to a single species of plant. 



Further information on the subject of diseases of 

 plants caused by parasitic fungi may be obtained from 

 the following books: — 



Ward, H. M. Diseases of Plants," S.P.C.K., London. 

 Duggar, B, M. Fungous Diseases of Plants,'- iqoq, Ginn aad 

 Company. 



Massee, G. Diseases of Cultivated Plants and Trees,"' Dwck- 

 wortb, igio. 



