VOLUME XXIX NUMBER 3 
POTANICAL. GaAveL ee 
MARCH, 1900 
THE HAUSTORIA OF THE ERYSIPHE/E. 
GRANT SMITH. . 
(WITH PLATES XI AND XI!) 
HISTORICAL RESUME. 
THE early literature on the Erysiphex is of historical interest 
chiefly. Until the middle of this century the need of exhaustive 
observations of the phenomena exhibited by plants had not been 
felt by botanists generally. The study of plant structure as a 
means of revealing functions had not been established as opposed 
to the study of structure as a means of revealing relationships 
in plants. Hence, though the destruction of crops by parasites 
had been known since the time of the Greeks and Romans, the 
idea of parasitism had as yet a vague and erroneous definition. 
By the middle of the century, however, it seems to have been 
quite generally accepted that parasitic fungi are nourished in 
Some way by their mycelium, ‘‘by imbibing juices impregnated 
with the peculiar principle of the matrix on which they grow” 
(28). Thus, though this statement was extremely vague, it 
looked in the right direction. The mildew of the peach, rose, 
etc., had long been included in lists of fungi by systematists, yet 
the Study of the structure of the fungus had proceeded only to 
figuring pieces of hyphe with their conidiophores and conidia. 
There was little information at hand, therefore, to assist in 
understanding the nature of a widespread grape disease soon to 
be produced by one of these Erysiphee. 
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