334 NOTES AND MEMORANDA. 



On these insufficient grounds a report was spread in 

 this country that the organisms described by me were 

 the same Avith Dr. Sadebeck's Pythium Equiseti, and the 

 * Journal of Botany ' for March last stated, in reference to 

 Pythium Equiseti, that it had "lately been attempted to 

 connect this fungus with the oospores of Peronospora infes- 

 tans." Dr. Sadebeck can hardly be said to have made such 

 an attempt, for in a very kind letter that he wrote me on 

 March 2ord last he said the presumed identity was a mere 

 *' supposition," thrown out in a preliminary paper, that he 

 was wdthout experiments from which to form a definite con- 

 clusion, and that he had not been able to infect the Potato 

 plant artificially with the Pythium. 



Dr. Sadebeck's excellent paper, and the evident strong ex- 

 ternal resemblance of his newly discovered plant to mine, 

 made me extremely desirous of seeing the Berlin plant, but on 

 writing to Dr. Sadebeck to this effect he replied that he had 

 no specimens. It therefore only remained to look out for the 

 parasite here, and I was fortunate enough to enlist the good 

 services of Mr. B. D. Jackson, F.L.S., who sent me some 

 capital specimens of Equisetum arvense from Snodland, Kent, 

 on April 25th. The first piece of Equisetum I examined 

 under the microscope displayed the presence of fungus spawn 

 ramifying amongst the tissues ; so, from experience gained 

 of the habits of some of the lower fungi, I half submerged the 

 specimens of Equisetum and kept them covered up in a dark 

 place. In ten days the Equisetum plants were dotted inside 

 and out with gelatinous patches, and every patch was a mass 

 of Pythium Equiseti. Though bearing a strong resemblance 

 to the early condition of the bodies found by me in the Chis- 

 wick Potatoes, yet Pythium Equiseti is clearly not the same. 

 Mr. Berkeley, who has seen both plants, writes me that 

 he considers them " decidedly difterent." I have been 

 unable to infect Potato plant with the Pythium or the 

 Equisetum with my Potato oospores. My experiments, 

 therefore, agree with the results obtained by Dr. Sade- 

 beck, and the two parasites may be considered different. 



A few lines should here be given regarding the parasite 

 found by Dr. Sadebeck on Potatoes. Pirst of all it may be 

 said that De Bary, Avho also, it seems, met with a new para- 

 site on Potatoes, could not make it artificially take possession 

 of the living Potato plant, and principally for this reason he 

 refers the parasite, not to Peronospora, but to Pythium. Dr. 

 Sadebeck, however, found his fungus in possession of the 



