96 



wholly on one host plant, altogether omit some of the 

 spore forms from the life story. Whilst showing: 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," igog, Ginn and 

 Company. 



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

 worth, igio. 



