58 Ergot and Clover Sickness [CH. 
have the appearance of circular or oval cells, these 
being the cut ends of the hyphae. 
Sclerotia sown just under the surface of damp earth 
or sand and kept in the open air begin to germinate in 
the spring. Small lumps at first form on them and 
eventually these take the form of short drum-sticks, 
the thickened portions being carried above the ground 
(see Fig. 20). On cutting sections these heads are 
found to contain a number of flask-shaped cavities in 
which are a number of club-shaped bodies known as 
asci, which in turn carry eight needle-shaped spores 
known as ascospores. 
Fig. 20. A sclerotium of Claviceps purpurea which has germinated. 
In the ordinary course of events some of the 
sclerotia fall to the ground and others are harvested. 
Germination of the sclerotia takes place in the spring 
in the ground. Some of them fall to the ground 
naturally and others are often sown with the seed. 
The ascospores are produced about the same time as the 
host plants flower. The spores are carried about by 
various agencies and some of them reach the flowers 
of the host plants. Here they germinate, putting out 
germ tubes which penetrate the flowers at their base. 
The mycelium formed from the germ tube grows 
through the base of the flower and then spreads over 
the surface covering the portion which normally 
