CLAVICEPS 481 



C. PYEENOMYCETES 



CLAVICEPS PURPUREA (Ergot) 



I. This Fungus is found infesting the ears of various Grasses : it 

 is very prevalent on the Rye, and is commonly styled the Ergot of 

 Rye ; but it is also to be seen on other Grasses, e.g. on Lolium 

 perenne, Glyceriaflmtans, &c. 



Examine specimens of ergotised Grasses taken in the dormant 

 condition in autumn or winter : the arrangement of the parts will 

 be found to be normal, but often, in place of the normal ovary, 

 there may be seen an enlarged, hard, dark-purple body, which is 

 easily detached : this is the sclerotium of the Fungus. Note at 

 the apex of the sclerotium a lighter coloured, easily detached 

 body : this is all that remains of the gonidiophore (Sphacelia 

 form) which is produced in early summer, and is now dry and 

 shrivelled. 



II. Cut transverse sections of the sclerotium in the dormant 

 winter condition : mount in glycerine, and observe under a low 

 power 



1. The irregular outline of the section, and compare this with 

 the whole sclerotium, which is often marked by longitudinal 

 grooves or slits. 



2. The external dark -purple covering. 



3. The internal, dense white mass. 



Examine a fine section closely, under a high power : it will then 

 be seen that the whole is composed of a pseudo-parenchymatous 

 tissue, with relatively thick cell-walls, and abundant oil stored 

 in the cells : this collects in large globules on and about the 



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