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EESEAECHES INTO THE OOSPORES OF 

 SOME FUNGI. 



By the Rev. J. E. Vize, M.A., F.E.M.S., &c. 



A CONTROVERSY SO hot and strong has long been going on about the resting spores 

 of Peronospora infestans, that these atoms in creation have assumed a gigantic 

 proportion. With this idea in mind I have, during the past season, been paying 

 attention to the resting spores of various plants, besides those of the potatoe 

 disease, and shall hope to work at them as opportunities ofifer. Except with the 

 genus Cystopus they are not very easily found, which circumstance arises, I 

 imagine, from the fact that Cystopws develops its oospores very soon after its 

 conidia are visible, whilst Peronospora does not, at all events not so transparently 

 as the other genus, nor is their locality so easily ascertained. 



I will proceed at once with those species in Peronospora which I have 

 detected. 



With regard to Peronospora Schleideniana (De By.). I remembered last 

 summer having obtained some onions with this fungus in the acrospore state, and 

 therefore determined to go and obtain, if possible, some specimens to examine for 

 the resting spore. Fortunately, the garden was as a rule neglected, so much so 

 indeed, that the onions, to my great relief, had not been disturbed. I found them 

 in every state, from healthy onions to very rotten ones. Taking them home for 

 examination, I saw a great number of the ubiquitous Sphieria herbarum, and after 

 much search, especially in the most decayed portions, found, very sparingly 

 scattered indeed amongst the material, a few genuine oospores. All traces of the 

 raphides of the onion had gone — so had all the chlorophyll ; the oospores were in 

 the brown putrid magma, composed, I believe, of the oil cells of onion. That I 

 expected to meet with a good deal of trouble in getting the oospores was a fact, 

 because the Peronospora in its summer state was very scarce in the onion bed. 

 One thing struck me as being singular, namely, the small size of the oospore 

 compared with the large size of the acrospore, which is the largest acrospore I 

 know. The date on which the winter spore was found by me was the 29th of 

 February. 



My opinion as to the rarity of meeting with the oospore of this fungus was 

 confirmed by the fact, that towards the end of August this year, I could not find 

 any trace of the same in the decayed leaves, although some weeks previously they 

 had been prolific in the acrospores. 



Whilst searching for the Onion Peronospwa, I recollected that the same 

 garden bad grown a plentiful crop of Peronospora gangliformis on lettuce. The 

 dead stems were lying on the ground, and when I looked for the oospores they 

 were to be found in immense numbers. Their exact place was very regularly 

 marked. The stem of the lettuce plants I cut up with a knife. In its interior 

 are parallel columns of spiral vessels, forming very beautiful objects for the micro- 



