DISPERSAL IN CUP FUNGI 305
of developing accessory methods of reproduction. Let me
take one very familiar example : Sclerotinia fructigena. This
causes the brown soft rot of apples and other rosaceous
fruits. In early autumn, rotting apples are to be seen both
attached to the tree and lying on the ground beneath. On
the brown rotten apples pustules of the fungus are produced
bearing dry, powdery spores (conidia) in branched chains.
These pustules usually occur in concentric circles. The
conidia are wind dispersed or carried by wasps to healthy
fruit and so the brown rot spreads. Some of the brown,
rotten apples shrivel up and dry, remaining attached to the
tree. These mummified fruit really consist of resting fungal
tissue contained within the skin of the apple. These over-
winter and may give rise to fresh conidial tufts in the
following year and so initiate next season's attack. How-
ever, the mummified apple may produce the "perfect"
stage. This has not been observed in this country, but is
reported from Denmark. If a mummy gets buried just below
the surface of the soil, it may give rise in the ensuing year,
after its winter rest, to a stalked apothecium which grows
up above the soil and from which ascospores are discharged
into the air.
This, perhaps, shows how unconservative are the fungi.
They are quite prepared to scrap an old mechanism and
develop a new. They are great opportunists.
In conclusion, let me say that the Cup Fungi—the
Discomycetes—represent a neglected group of fungi. Very
few British field mycologists have paid much attention to
them. There is great scope here for the work of the enthu-
siastic amateur who knows how to use a microscope.