214 THE FLORIST AND 



the mycelium which bears at the same time the necklace beads of the Oidi- 

 um, and the fruits of the Erysiphe, filaments peculiar to either; for, by 

 careful examination , it will be perceived that the conceptacles of the Erysi- 

 phe actually proceed from the same threads which elsewhere give rise to the 

 generating pedicels of the naked spores. 



In the second place, in order to be certain that there is no real parasitism 

 in the case, and that there are not two distinct plants associated together, 

 but only one endowed with several organs of generation, it is sufficient to 

 consider the many-seeded fruits before spoken of, which vary so much in 

 their form that they present every possible intermediate stage between the 

 spores of the so-called Oidium and the ascophorous conceptacles of Erysi- 

 phe, the most perfect reproductive organs which nature has given to these 

 fungi. 



These many-seeded fruits being thus present in the Oidium in the shape 

 of the separate articulations of the necklaces of spores, and on fertile Erysi- 

 phe as concepticles exteriorly identical with their perithecia, evidently unite 

 Oidium to Erysiphe, and furnish the best proof that that they are one and 

 the same genus. In other words, the organs in question do not," as M. Am- 

 ici would induce us to believe, solely constitute the reproductive apparatus 

 of Oidium, supposed to be a peculiar genus, but they really belong to Erysi- 

 phe as much as the naked spores of Oidium, and represent a mode of prop- 

 agation intermediate between that by spores and that by thecigerous con- 

 ceptacles. 



From this fact it may be concluded that Erysiphes, like many other fungi, 

 possess at least three distinct modes of propagation, and three special sets 

 of organs for that purpose. In the order of their successive development, 

 the first and most simple is that which consists in naked spores, disposed in 

 necklace-like rows, which I call conidia ; then come conceptacles of various 

 forms, full of innumerable and very fine seeds, and to which I have given 

 the name of pycnidia ; and finally, the more perfect globular, black spo- 

 rangia are produced, in which one or more few-seeded thecae are engen- 

 dered. 



This being admitted, it is evident that the Oidium Tuckeri, with its naked 

 terminal spores and its many-seeded fruits, represents an Erysiphe reduced 

 to its two secondary modes of propagation; so that the most important 

 blank remaining to be filled up in the history of this enemy of the Vine 

 consists in determining to what species of Erysiphe it belongs. Now, until 

 its ascophorous fruits shall have been observed, the determination of its spe- 



