49 



Vine Disease. 



M. Tulasne has had the goodness to communicale to us his " Notes on 

 the Fungus which causes the Fine Disease J'^ extracted from the " Comptes 

 rendus des Seances de rAcademie des Sciences, vol. xxxvii., Seance 

 du 17 Octobre, 1 853," of which the following is a translation : 



The Fungus which has committed such ravages on the Vine, and 

 which is now well known under the name of Oidium Tuckeii (Berk.), 

 consists of a network {myceliurn) of white loose filaments, which covers, 

 here and there, the green and healthy parts of the vine, and causes the 

 formation of brownish or blackish spots. From these filaments, which 

 are all superficial, or external on the epidermis of the infested plant, 

 spring thick tufts of simple, stifi", pointed stalks, the ultimate point of 

 each of which quickly becomes a large oval cell, as capable of propa- 

 gating the fungus as any true seed could l)e. Independently of these re- 

 productive bodies, the Oidium Tucheri produces brown, generally pedi- 

 cellate fruits, coated with a cellular membrane, and containing very 

 minute seeds, equally capable of germinating. These fruits are com- 

 monly larger than those swollen acrogenous bodies which are described 

 above, but they are not always so : they are of the same form, and are 

 often borne on the selfsame footstalk, almost appearing as if they 

 were caused by a transformation of the normal seeds. M. Cesati was 



the first, I believe, to recognize the existence of these fmits ; but he did 

 not suspect that they belonged to the Oidium^ but attributed their pi'e- 

 sence to tfie reproductive organs of a peculiar fungus, to which he gave 

 the name of Amjpdouyces Quisqtialis (see Klotzsch's Herb. Viv. Mycol. 

 Cent, xxxvii. no. 1669, b. anno 1851). M. Amici has, since, correctly 

 referred tliera to the Oidium Tiidceri^ of which he considers them to be 

 the most perfect organs of propagation (see the Atti dei Gcografi di 

 Firenze, vol. xxx, anno 1852). I have myself found these peculiar 

 organs on the Vines which were diseased in the environs of Paris, and, 

 in common with the above-quoted authors, I have seen that they were 

 sometimes elongated, and sometimes globular, and that among the 

 latter, several were perfectly spherical, and sessile on the byssus which 

 engenders them. These observations have led me to the conclusion 

 that Oidiutn Tuckeri (Berk.) is of a very difi^erent nature from the view 

 which other writers have hitherto taken of it. There is a genus of 

 small parasitical fungi, common iu our country, which, iu their rnrlicst 



VOL. VI. 



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