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1.] MICROSCOPIC PLANTS. 17 
are the cause of mildewed corn, and recent scientific 
investigations have shown that there is truth in the 
belief, which is not always the case with popular 
adages. Dr. M. C. Cooke, in his “ Fungi,” gives the 
following :— 
“ There is a village in Norfolk, not far from Great 
Yarmouth, called ‘ Mildew Rollesby, because of its 
unenviable notoriety in days past for mildewed corn, 
produced, it was said, by the Berberry bushes, which 
were cut down, and then mildew disappeared from 
the cornfields, so that Rollesby no longer merited its 
soiriquet, It has already been shown that the corn- 
mildew (Puccinia graminis) is dimorphous, having a 
one-celled fruit (Z7ichobasis), as well as a two-celled 
fruit (Puccinza). The fungus which attacks the Ber- 
berry is a species of Cluster-cup (cidium berberidis) 
in which little cup-like peridia, containing bright 
orange pseudospores, are produced in tufts or clusters 
on the green leaves, together with their spermogonia. 
De Bary’s observations on this association of forms 
were published in 1865. In view of the popular 
belief, he determined to sow the spores of Puccinia 
graminis on the leaves of the Berberry. For this 
purpose he selected the septate resting spores from 
Poa pratensis and Triticum repens. Having caused 
the spores to germinate in a moist atmosphere, he 
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