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JOUBHAL OF THE EOYAL HOETICITLTTTEAL SOCIETY. 
XI. On Fungoid Diseases of the Vine. Part I. By Dr. M. C. 
Cooke. 
[Read at Meeting of Scientific Committee, loth January, 1378.] 
The Vine is such an important object in the eyes of the horti¬ 
culturist that it scarcely needs any apology for offering to this 
Committee consecutively at its meetings a summary of the 
different species of Fungi which have at divers times and in 
different countries been found living and thriving, sometimes 
inflicting considerably injury, upon this valuable plant. By 
doing this it is hoped that those who read from time to time the 
proceedings of this Committee may he assisted to some information 
which could not otherwise he very readily procured, whilst the 
Committee itself will not he impatient of being reminded of many 
things with which its members may individually be well cognisant 
in furtherance of a public object. 
Oidium Tuckeri , Berk.—Commencing with the well-known 
Vine-Mildew, under its old name, it may be well to confess that 
we can add nothing to what all European horticulturists have 
acquired by a painful experience. So much has been written con¬ 
cerning the Oidium , that it will be almost sufficient to mention its 
name, and pass on to other and less familiar parasites. Tech¬ 
nically, all we know of this Fungus is the condition of an Oidium, 
whilst we have no doubt whatever that, like the Hop-mildew 
and the American Vine-mildew, this is only an imperfect or 
conidial condition of some higher Fungus belonging to the genus 
Erysiphe , or some allied genus. It seems to be extremely 
probable that it is but the conidia of an Uncinula , of which the 
mature or sporangial condition has not yet been observed. Our 
reasons for referring it to this genus are based on the known 
affinities which certain genera of parasites have for allied plants, 
and since we know that two or three species of TJncinula are 
developed in other countries upon species of Vitis, whilst but one 
instance is known of a true species of Erysiphe or Sphcerotheca 
being found even on a kindred order of Phanerogams, we assume 
it to be a probability that the Vine-disease is a conidial condition 
of a species of Uncinula. Add to this the fact that there is 
scarcely any appreciable difference between the conidia of 
Uncimda spiralis and the Vine-disease, and this supposition is 
strengthened. 
It is scarcely possible to refer to this subject on the premises of 
