370 
On the Potato Disease. 
On examining some sickly-looking plants of tares lately, AAhich 
I found here and there amongst a very tine healthy crop, I was 
also rather surprised to find that this diseased appearance, instead 
of being produced by Botrytis viciae (as it has been supposed to 
be), was, in every instance, owing to blotches of canker, some on tlie 
stalks, others underground; the greater number of diseased 
plants having no mildew at all on them ; others, however, pro- 
ducing fine crops of Botrytis viciai on the leaves, and Monilia 
racemosa, or an allied species, on the ulcerous spots on the stalks 
(fig. f). But I cannot perhaps name any plant by which the 
F. 
X GangrenoHs Ijlolclics on tare plant. May, lR-16. 
1. ]lotrytis Vicix on those leaves. 
2. Monilia racemosa on stem (^none on lower bloldi). 
real cause and nature of this disease may be so easily and clearly 
demonstrated as the common scarlet geranium, which, although 
considerably more robust than the potato, is, if ill treated, very 
liable to canker. Often have I seen this favourite plant, after 
enlivening our flower-beds during the summer, taken up in the 
autim^n (usually after being a little nipped) and thrust into a dark 
shed, for want of better accommodation, and watched ihe "rise 
and progress " of the blotches on the stalks and leaves until the 
