424 Prof. H. Marshall Ward. The Relations between 



yellow and dies, more often only a part of it goes,* and in many cases 

 the disease is confined to individual organs — leaves, flower-buds, fruit, 

 &c, as the case may be. When the disease occurs amongst stored 

 chestnuts, carrots, parsnips, &c, the tissues become speckled, and in 

 many cases this spreads till they are rotten throughout ; and similarly 

 with stored bulbs, corms, and tubers, &c. 



Wherever the disease is rampnnt we find the colourless, septate, 

 branched fungus mycelium in the dead and dying tissues, and usually 

 emitting hyphae, which grow into the damp air and bear the conidia 

 in abundance. In some cases, however, these aerial conidiophores 

 have not been observed,f and the habit of producing them appears 

 to be lost, though in every other respect the behaviour of the 

 mycelium is the same in all the cases thoroughly examined. 



Ttg. 9. Botrytis cinerea. The upper figure represents a tuft of the conidiophores 

 breaking through the epidermis of a grape (magnified) ; the lower one is one 

 of the conidiophores still more highly magnified. 



Some very remarkable facts have come to light during the last few 

 years concerning this mycelium and the conidia ; and as all the 

 species or forms which have been thoroughly examined agree essen- 

 tially in their physiological behaviour, I need no longer trouble you 



* A curious fact is sometimes observed — the small brown spot suddenly ceases to 

 spread, and the hyphse may be found in it in a dried-up, dormant condition for 

 weeks. See also ' Annals of Botany,' vol. 2, 1888, p. 356, and figs. 51 — -54. 



f JE.g., in de Bary's Peziza Sclerotiorum (Lib.). See " Sclerotinien und Sclero- 

 tinien-Kranlcheiten " (' Bot. Zeitg.,' 1886, col. 424). 



