496 
On Wheat Mildew. 
cut out of the hedge. He took one of the largest bushes and 
placed it in the middle of the field. Before reaping he found 
the straw, for some yards round the bush, injured by mildew, 
though not to the same extent as on the side of the field nigh to 
the hedge. 
A later volume of the Journal contains an able and lucid 
exposition of the parasitic fungi of the British farm, which had 
been delivered as a popular lecture by the Rev. Edwin Sidney, 
and among them is included the mildew fungus. 
Until the investigations of Tulasne and De Bary, nothing was 
added to the knowledge of the mildew, beyond what was con- 
tained in these papers. 
The belief held by Henslow, that rust and mildew were pro- 
duced by the same fungus, was demonstrated to be the case by 
Tulasne, who proved that the rust was an earlier stage in the 
life-history of the plant which afterwards produced the mildew. 
The relation between the barberry and the mildew was 
established still later by De Bary, who discovered that the 
cluster-cup or ^cidium on the leaf of the barberry was a still 
earlier state of the mildew than the rust. 
That a plant might spend some stages of its life in conditions 
and under a form different from its perfect state, Avas in harmony 
with obvious facts in the animal kingdom. The development of 
the grub living in the earth or swimming in the water, into a fly 
or beetle inhabiting the air, made one familiar with great changes 
in the life-history of an organic being. The perfect state was 
easily determined, because only in that state had the animal the 
power of producing eggs, and so providing for the continuance 
of its kind. But in these parasitic fungi, each stage ended in 
the production of spores, that is, of bodies equivalent in function 
to the seeds of flowering plants or the eggs of animals, and 
capable of developing fresh individuals. 
The structure of the fungus in the different stages of its exis- 
tence, as the ^cidium on the barberry, and the rust or mildew on 
the wheat, was so very different, that botanists could not enter- 
tain the notion that any organic relation existed between them, 
and those most intimately acquainted with these parasitic plants, 
were most decided in their views as to the absurdity of enter- 
taining such a notion. Especially did it appear improbable 
that the plant grown from a spore should have no resemblance 
to the parent producing the spore, but that instead it should 
belong to a group which the scientific student had widely sepa- 
rated from the parent. Within the last ten years our first 
authority in England wrote: "There has been a very unjust 
charge brought against JEcidium herheridis, a beautiful species, 
which attacks the leaves, flowers, and young fruit of the 
