B28 THE! FLORIST. 
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ORANGE MILDEW. “AND BLACK BLOTCH, , By 40 
Rosé trees ‘have, this year,‘been comparatively ‘little affected with the 
former, but much ‘affected with the latter; yet, where they: have been 
seized by’ either, their blooming, if) mot their ‘constitution, has been 
injured. I call the former “Orange Mildew,” becauseI see in a/book 
there is such’a fungus. In. the same work, “* Black’ Blotch?’ is also 
vspoken of as the effect'of fungus; but Ivhave my doubts on this point, 
as Ihave never been able with my: Petia to ca oe ee or 
eae relating to it. 
The following ’is’the aceount of two kinds of Orange Mildew, and thie 
first also speaks of brown blotches = io worg OS 
1. Evrineum griseum; forming broad grey; orange, ‘or Tore blotehes, 
which overrun the leaves of the Mountain — — Nichia ‘and 
other trees. 1 aV 
2.) Gicidium ranvéllatins ¢ehioh oebaaiontadle dee ouch thatlap “to 
Pear-trees in Hertfordshire.’ It-appears'first “like bright yellow ‘spots, 
and by degrees a liquid matteris exuded from thems ‘ab thersameé time 
small ‘conical processes appear in clusters from the under'side of ‘the 
leaf; these processes’ enlarge, ‘become fibrous, ‘open atithe sides*by 
annumerable slits, and/ thence discharge their spores: ‘This fungus often 
produces the most destructive consequences, gareviols upon the! leaves, 
stems, and fruits, generally ‘destroying’'the ‘tree. » Another's ‘Species, 
Beidium laceratim; sometimes spreads*over H awthors hedges, ‘and 
the common orange’ red mildew of the: Berbery is: Berderidis’ Cueidiwm. 
 This‘is all that can ‘discover'from books about orange mildew ~ 
leaf blotch, which I willnow describe, as:they have appeared-herey 
In my Rose leaves;this year; I) have observed in‘ the wieder of 
the leaves this orange blotch, ‘as if glued on; and hardly: removable with 
the finger-nail.On the upper side of the leaf there'is'a little darkened 
spot, just opposite the conical bunch. under the leaf. «From this‘ bunth 
the fungi break’ forth, and soon. overspread ‘the whole of! the’ leaves ’on 
both sides:, and by destroying the leaves ‘must do much anjuryeio |e 
This: is the same’ disease |that;’ in"previous communications, Tjshave 
called ‘‘rust,” from not knowing what to call it. . did not, this year, 
trouble myself to. pull/off the affected leaf; but another year, if spared, 
I shall do so. No matter, whether this is fungus or mycelium ; 
whether it is Hrineum griseum, Gicidium cancellatum, laceratum, or 
Berberidis, it shall be removed as soon as seen. I am determined to 
try weak solution of vitriol upon the leaves, both as a preventive and as 
acure. This mildew is as destructive as white, and,.as it quickly 
spreads, must be removed at once. It is like the. white mildew in this 
respect, viz., it destroys or impairs delicate trees more easily than. the 
robust. It is remarkable that deep-coloured Roses, as a class, are more 
delicate than those whose blooms are rose-colouréd, and are more easily 
destroyed or impaired by mildews than others. This may be attributed 
to their constitutions! weakness, for their colour is connected’ with a want 
of power to decompose carbonic acid gas, which is’ an “indispensable++ 
and the most indispensable—function in the vegetable’ kingdom: © If 
