On the Potato Disease. 3g5 
opinion that the botrytis took the initiative part in the late cala- 
mity. Indeed, I repeatedly rubbed leaves covered with it on the 
underside of iny potato-leaves without producing any effect what- 
ever; and I cannot but think that, if the leaves and stalks of the 
potato had undergone half as close an examination as to the state 
of their health at the commencement of the late attack, as thev 
have subsequently for the discovery of mucedinous filaments we 
should long smce have arrived at a more satisfactory conclusion • 
whereas, little more than ordinary notice was taken of the health 
of die plants, while the mildew was magnified by a power equal 
to /SO diameters. =^ I have observed betweenlwenty and thirty 
other kinds of fungi on the dead stalks of last year, as well as on 
diseased potatoes— of some of which I give figures, as they are 
very curious, and some of them I believe new ; and I think the 
fanding of them in such a situation confirms the general opinion 
that the proper food of fungi is, in almost all cases, matter at least 
in an incipient state of decay. I scattered the spores of many of 
these amongst the leaves of my plants also without injury to them 
One of these, however (fig. 5, c), I found at the bases of manv 
stalks at the time of taking up my crops last year ; and since, 
upon upwards of two hundred stalks picked up'indiscriminately 
both inside and out ; but, as it fructified freely durincr the winteV' 
both in my greenhouse and out of doors, I look upon^it merely as 
an attendant upon decay, not the cause of it. 
Another opinion existed, that the disease was caused by in- 
sects : and, if the swarms of green flies which I found during my 
examinations of the haulm last year, on the underside of tli'e 
leaves, had been generally observed, I should not have been sur- 
prised if such an opinion had been even more popular than the 
preceding. But the presence of this species has never, as I believe ' 
been publicly noticed in this country, although, in America, in 
18d», another species was observed by Dr. Harris,t in great num- 
bers on the potato-haulm and other herbaceous plants ; and he 
thinks they contributed as much as the dry weather to diminish 
the crop by puncturing the upper parts with their beaks, drawino- 
out the sap and poisoning the parts — for these shortly after 
withered, turned black, and in a few days dried up, or curled and 
remained stunted. The Doctor's odd description of their sin-ular 
habit of "dodging round" to the other side of the leaf to elude 
being taken, in addition to a general resemblance, left no doubt on 
my mind ot their being pretty closely allied to those which I 
ound ; but the Doctor describes his species as Phytocoris lineo- 
lans. I did not perceive that those I found did any harm I how- 
* 
The Rev. Mr. Berkeley's memoir, 
t " Treatise on Insects," 1841. 
'2 c 2 
