es, 2 
THE STUDY OF FUNGI. 149 
worms in France have suffered severely. Wasps have been seen alive 
infested with a growth which would eventually deprive them of life, 
Between twenty and thirty species of ascigerous fungi have been recorded 
as parasitic on insects. One of our British specimens is very beautiful. 
It grows in autumn on the pupz of moths buried in the ground, and is of 
a splendid orange-red colour, scarcely two inches high, its clavate head 
being covered with tubercles. The contrast between the scarlet head of the 
fungus and the green grass in which it grows is very gladdening to the 
sight of a mycologist who has never before seen it. 
The potato disease alsois afungoid growth. A popular idea prevails 
that the potato disease comes down with the warm rains of summer, and 
this notion originates in the fact that the leaves are seen to be diseased 
after the showers of July. When there is a dry season, the leaves are 
free from the brown spots which indicate the disease. But the rain by 
no means has the disease in itself; it only causes the spores to grow. 
Moreover, the spots on the leaves are not the first startings of the disease, 
they are only proofs that it is at work elsewhere. The first part affected 
is the tuber ; the resting-spore, (oospore,) which has lain dormant nearly 
the whole year, is ready to mature in June and July, and if it gets 
sufficient moisture sends out mycelium, which penetrates any tuber it 
touches, extends up the haulm, and goes to the leaves, there showing its 
presence by a brown spot. It protrudes through the stomata, forming a 
grey tint or bloom upon the leaf. This bloom consists of a branched 
growth upon which are borne two kinds of spores, both of which are 
capable of growth during the moist summer weather, but neither of which 
will exist through the winter. One kind of spore we call conidia, or dust 
spores; these are wafted to another leaf or stem, where they will grow, 
if they can find a stomate to enter. They will even start into 
existence on any damp spot, but die quickly unless they can meet 
with a potato or some closely related species. The other kind 
of spore is called a zoospore. Its structure is very different; 
it is capable of division into a number —say eight—of atoms. These 
have two lash-like tails, with which they can propel themselves for hours 
or even days together. They are more able to propagate the disease than 
the others, because of their wonderful power of locomotion; hence a 
warm wet day or night is very favourable to the spread of the disease. 
But the question arises, if these two kinds of spores do their 
destructive work only in the summer and die, how is the disease 
propagated through the winter? This is the puzzle which has harassed 
the minds of the ablest men of the day, and the solution of it has gained 
for my friend Mr. Worthington G. Smith a gold medal. Mr. Smith 
collected a great number of the brown-spotted leaves, and kept them 
moist during the whole of the winter at the cost of a «good deal of labour 
and trouble. The consequence was that these moist leaves produced a 
quantity of mycelium threads, including the long-looked-for missing link, 
which is called the resting-spore. If it could be destroyed we should be 
free from the potato disease. Every diseased potato you leave to be 
buried in the ground deposits vast numbers of these resting-spores, the 
haulm you put tothe manure heap to rot for future use only increases 
