342 



DISEASES OF CULTIVATED PLANTS 



the seed, which, however, shows no sign of disease, but when 

 sown produces a smutted crop. Seed should be sown that 

 was produced in a crop free from smut. 



Scilla smut {Ustilago VaillanHi, Tul.) occurs very com- 

 monly in the anthers and ovary of Scilla bifolia and other 





In,. to2. Ear of barley attacked bj Ustilago hordei. 



species ; Gagea lutca, also in species of Muscari, BeUevalia, 

 etc. The mycelium of the fungus is perennial in the stem or 

 cushion of the bulb, and from thence passes up the flower- 

 stalk and into the anthers or ovary each year; hence when a 

 plant is once infected it remains so for all time, and it is 

 advisable to remove such bulbs, as the flowers are unsightly 



