ItOrAL HORTICULTURAL SOCIETF. 
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It seems quite certain that its appearance in this country has 
been equally recent, as no trace of it appears in any of our Floras, 
nor, with the exception just mentioned, is there any specimen 
amongst the numerous individuals of the genus from various 
quarters in my Herbarium. I have, indeed, another species on 
Malvaceae — viz., Puccinia Ahutilt, B. & Br. Fungi of Ceylon, No. 
816, on Ahutilon graveolens^ which also has been gathered by Mr. 
Ayres, on a species of Sida^ in Mauritius. This has much shorter, 
obtuse, and very different pseudospores. I have also a closely- 
allied species, Puccinia sepuUa, B. &. Curt., Proc. Am. Ac. iv., 
p. 126, on some uncertain plant. 
P. malvacearum is figured by Corda from specimens com- 
municated by Dr. Montague, Ic. Fasc, vi., p. 4, t. I, f. 12, and 
my own analysis exactly accords with his figure. 
Mr. Carson's specimens were received in this country in 1865 
but we have no information as to the time of the first appearance 
of the parasite in Australia. It would perhaps be assuming too 
much, in the absence of direct information, to give an opinion that 
the present disease might possibly have been derived from those 
specimens. Some years, however, elapsed before Hollyhocks were 
attacked in this country, and more before the parasite spread to 
our common Mallows. 
The sudden appearance of parasites is extremely curious. 
Nothing was known of Peronospora infestans in Great Britain till 
1844. There is not a trace of it in any old Herbarium — as, for 
example, in those of De Candolle or Sowerby, though species quite 
us obscure are contained in each, audit appears more than probable 
that it came from Chili into the United States, from whence it 
travelled here, as the disease, according to Monsieur Gay, has been 
known in Chili from time immemorial, though the cause was not 
ascertained. As the Peronospora can be conveyed by tubers, its in- 
troduction is readily accounted for, but unless the Hollyhock disease 
in this country and in France was really derived from the Australian 
specimens, which is not impossible, we can only have recourse 
to the fortuitous introduction by means of the air, After the 
recent observations of Dr. Cunningham at Calcutta, which show 
that such a marvellous host of Fungus spores float about in the 
air, in which they seem even to germinate, and so are at once ready 
for propagation where they find a fitting resting-place and favour- 
able climatic conditions, its introduction need not be matter of 
surprise. 
The characters of the species as given by Montague in the " Flora 
