T-k^IB OF COHTEMTS 



I I. Introduction Pi.^,e 



IIo General consideration of the disease • - • • 1 



CoKmon names , 1 



Description^ , , 1 



Geographical distribution 2 



Economic importance k 



History 5 



j 



ill . The causal organi sms , 



1 , Claviceps purpurea , 5 



^ a. Hosts 9 



b. Tascononigr 15 



( 1) Sclerotial stag©. 15 



( 2 J Ascigerous stage l6 



( 3) Conidial stage • l6 



c. Morphology 17 



( 1 ) oclerotiuin • . • 17 



(2) Stroma 13 



(3) Sphacelia '. 20 



d . Physiology. 21 



e . Pathogenicity 23 



<% fo life history of C laviceps purpurea in relation to pathogenesis .-23 



(1) Seasonal developnEnt of the disease 23 



" ( 2) Production of spore s ♦ ^ 



(3y Viability and longevity of sclerotia 29 



(4; Viability and longevity of conidia 31 



( 5] Dissemination of spores 32 



^# {aj Di sseimnation of conidia " • 32 



•> _ 



(b) Dissemination of ascospores • •r • 35 



