Observations on the Biology of Botrytis cinerea. 
BY 
F. T. BROOKS, B.A., 
Frank Smart Student , Cams College , Cambridge. Late Scholar , Emmanuel College. 
With four Figures in the Text. 
T HOUGH the connexion between Botrytis cinerea and Sclerotinia 
Fnckeliana had been long surmised, no definite proof of the identity 
of these two forms was forthcoming until the recent appearance of a paper 
by Gy. de Istvanffi, entitled ‘ Etudes microbiologiques et mycologiques sur 
le rot gris de la vigne — Botrytis cinerea ou Sclerotinia Fnckeliana! Istvanffi 
has come to the conclusion that Botrytis cinerea is indubitably the conidial 
stage of Sclerotinia Fnckeliana. This fungus causes a virulent disease of the 
fruit and foliage of the vine on the Continent. The diseased areas at first 
produce abundant conidiophores of the Botrytis type and sclerotia are 
formed later. Istvanffi has shown that these sclerotia, upon germination, 
produce either conidiophores of the Botrytis type or apothecia such as have 
long been known to characterize Sclerotinia Fnckeliana . In this country, 
Botrytis cinerea is generally found growing saprophytically upon the dead 
leaves and flowers of many plants. After being nourished in this way the 
mycelium has frequently the power of destroying living tissues by the 
secretion of a poisonous substance. 
The group of fungi to which Botrytis cinerea belongs has been of 
particular interest to the plant pathologist ever since De Bary published 
his researches entitled ‘ Ueber einige Sclerotinien und Sclerotinienkrank- 
heiten.’ In that series of papers he dealt mainly with the life-history of 
Sclerotinia Sclerotiorum, especially in so far as it was the cause of a disease 
of the roots of Beta y Raphanns, and Daucus, and the foliage of Phaseolns 
and Petunia. This fungus has no conidial fructification, but produces 
abundant sclerotia, which germinate after a period of rest and give rise 
to apothecia. De Bary found that the ascospores were unable to cause 
direct infection of the living host-plant ; if, however, the ascospores were 
sown upon some saprophytic medium, the young mycelium produced, upon 
[Annals of Botany, Vol. XXII. No. LXXXVII. July, 1908.] 
