120 The Besting Spores of the Potato Fungus. By W. G. Smith. 
they are not unlike the seeds of germinating Dodder, for if they 
cannot find a proper host they die. But if Potato plants happen to 
be near the corrosive mycelium, it at once penetrates and enters 
the tuber or haulm. The tuber cannot produce simple or zoospores 
if buried, but in the haulms the mycelium doubtless soon grows 
and produces both these forms of fruit. These are at once carried 
by the air into the breathing pores, and the whole history of the 
fungus here described is re-enacted. 
Since my observations on these bodies were published in the 
‘Gardeners’ Chronicle’ for July 10, I have (by the courtesy of 
the Bev. M. J. Berkeley) had an opportunity of carefully ex- 
amining and measuring the original specimens of Dr. Montagne’s 
Artotrogus, found long ago in the intercellular passages of spent 
Potatoes, and from the first considered to be the secondary form of 
fruit of the Peronospora by Mr. Berkeley. I have no hesitation 
whatever in saying that the bodies lately seen and now figured by 
me are positively the same with Dr. Montagne’s in every respect, 
and when reflected and trac'ed with the aid of a camera lucida 
no difference whatever can be detected. The bodies seen in Dr. 
Montagne’s specimens are, without doubt, the fertilized and half- 
mature resting spores, and therefore dense, uncollapsed, and exactly 
the same in size, habit, and colour with mine when in the same 
stage of growth. After the lapse of so many years the threads, as 
might be expected, have more or less perished, but it is not difficult 
to find traces of antheridia in the specimens. 
For comparison, the original figure of Artotrogus (Fig. 3) is 
here exactly reproduced to the same scale as my drawings, from 
vol. i. of the ‘ Journal of the Boyal Horticultural Society,’ to show 
the similar nature of the bodies illustrated. Since this was engraved 
Mr. Berkeley has kindly forwarded Dr. Montagne’s original draw- 
ings to me for examination, and I may as well say they contain 
many more threads and oogonia than are shown in this cut, and 
they are also more like my organisms now brought forward. As 
for some of the bodies being shown as if within the threads by Dr. 
Montagne, I consider this of little moment, as the oogonia are at 
times almost or quite sessile, and consequently, when seen in some 
positions, they put on an appearance of being within the mycelium, 
whilst in reality they are upon or under it. As for the echinulate 
body at 0, described as a “ mature spore,” it is not exactly like 
Dr. Montagne’s original drawing, which is shown as furnished with 
a thick wall, and there are no “mature” spores in his specimens. 
After a most careful and searching examination of the latter I can 
find no such bodies, but there are several spores on the two mica 
slides which put on a spuriously echinulate appearance, which is 
owing to the collapse of the coat of cellulose, as suggested by me as 
a possibility when I read my first paper. 
