Types of Abnormal Apothecia Produced by Sclerotinia Sclerotiorum

SUMMARY

Abnormal apothecia of Sclerotinia sclerotiorum were observed during a study of apothecial morphogenesis. Three groups of abnormal ascocarps were distinguished: those produced by dichotomous and multiple branching of the apothecial initial; secondary apothecia which developed by proliferation from an aborted primary disc; and those formed by extreme convolution of the primary disc. Decapitation of actively elongating apothecial initials resulted in the formation, in some instances, of small terminal discs and, in others, of small, secondary apothecia in positions lateral to the decapitated initial. When decapitated initials were detached from the parent Sclerotium the disc did not become fully differentiated.