DISEASES OF CEREALS AND GRASSES 



D!) 



to rust and still maintain the other essential char- 

 acters, e.g. Little Joss. 



3. Sow autumn grain somewhat late, and put in 

 spring sown early. 



4. Drain the land. 



5. Climatic conditions have their influence, but 

 are beyond control, 



Note. — A large number of rust fungi attack various garden 

 plants and would have been described had space allowed. 



IV. Ergot {Claviceps purpurea). Class: As- 

 COMYCETE.E ; Order : Pyrenomycetales, 



Found on cereals and grasses, but especially 

 common on rye and rye grass. This fungus pre- 

 vents healthy development of the grain, and the 

 sclerotia contain poisonous substances — ergotin and 

 cornutin^ — -which are said to be injurious to stock. 



Symptoms. — -Ergotted ears have large black 

 bodies — the sclerotia — taking the place of some ot 

 the grains, and projecting beyond the other parts, 

 making diseased ears easily recognizable (Fig. 



15. A). 



Cause. — The above sclerotia are the resting 

 bodies of the fungus Claviceps purpurea which has 

 taken up its abode in the ear, thus causing the 

 disease. \\\ early winter they fall to the ground, 

 and can withstand drought and cold, hi spring 

 they germinate ^ in the soil, giving rise to numerous 



^ May be collected and germinated in the laboratory in moist 

 sand. 



