DISEASES OF THE QUINCE. 87 
and opening out with a multitude of cups, notched at 
the edge, and shedding a profusion of yellow dust, which, 
as it falls, reminds one of the shower of sparks from an 
ascending rocket. ‘The cups are bell-shaped, edged with 
a pretty fringe around their margins; and are so nu- 
merous as to entirely girdle the twig or half cover the 
fruit. 
These cups, called peridia by mycologists, appear to 
have burst through the outer covering of the bark on 
Fig. 57.—STEM BETWEEN BUDS AFFECTED BY THE RASTILIA AURANTIACA, 
the twigs and the skin of the fruit. The cups some- 
times rise a tenth of an inch above the surface, with the 
lower parts attached to the substratum. ‘The bursting 
peridia shed a liberal shower of their golden dust around 
them, which is scattered by the winds, carrying the spores, 
or, more strictly, the protospores, because they produce 
the true spores or fruit, so that each grain of this dust is 
the seed of more of these epiphytal plants. Before the 
oidium or fungus bursts out in the clasters of cups so 
prolific of dust, the surfaces of affected parts show numer- 
