STATE HORTICULTURAL SOCIETY. 21 T 



populina ; but as one name for one plant is enough, especially when it 

 happens to be so long, the first has fallen into disuse. There are, how- 

 ever, instances in which, so iix as is known to the writer, the second form 

 of fruit (winter spores) is not produced, hence the name may yet be 

 preserved for such species. Before leaving this subject, it should be men- 

 tioned that the Lombardy poplar is attacked by the same destroyer, and 

 this may be one of the reasons of its short life. 



Clover, both white and red, but especially the former, was the host 

 during the whole summer of a parasite quite different to any of the above. 

 This formed small black dots on the leaves, so readily seen that few 

 persons who take the trouble to read this account could have missed 

 observing them. Each sooty spot is made up of dark-colored pointed or 

 beaded threads, closely crowded together, but well filled in with oval 

 once-partitioned spores. The beaded threads rise perpendicularly to the 

 leaf, and the spores appear as if sifted down among them. No doubt, 

 however, they would be seen borne on the threads, if the manipulation 

 should be delicate enough to show them without disturbance. The name 

 is Polythrincium trifolii. But this is probably only a first form, another 

 form, quite commonly found with this, bearing the cognomen of Dothidia 

 trifolii. Not uncommonly, as a thin section of one of the dots is sub- 

 mitted to the microscope, myriads of minute moving particles are seen, 

 which are supposed to be the spermatia of the latter, and very similar to 

 those described in the Austrian pine fungus. An interesting question in 

 regard to the "slobbering" of the clover-fed horse here presents itself. 

 Is this the result of this fungus? It is well known that the phenomenon 

 does not appear until about the time of flowering of the clover, but it is 

 not so well known that the flowers themselves are in any way connected 

 therewith. The microscope will doubtless some day determine this 

 matter. 



The parasites now classed in the family PeronosporecB, and in the 

 two genera Peronospora and Cystoptis, are among the worst pests of the 

 fields and gardens. Those of the former genus are especially destructive. 

 They blight like contagion, and wither like death itself. Over forty 

 species of the Peronosporas are known in Europe, while only six have so 

 far been observed in this country, three of which came under the notice 

 of the writer within the limits of time fixed for this paper. These are 

 Peronospora infestans, on potatoes and tomatoes ; P. gangli/ormis, on 

 lettuce ; and P. viticola, on grapes. The species of the genus Cystopus 

 do not seem to have the destructive effects of the former, yet must cause 

 much loss of vitality to the supporting plants. They appear as small 

 scabs or blotches on leaves and green stems. Cruciferous plants, espe- 

 cially with us horse-raddish and cabbage, are commonly thickly spotted 

 by the parasite. The weeds known as purselane (pusly) and pig-weed 

 or red-root (A marantus reiro/iexus) are s\m\\a.T\y "scabbed," and even 

 the ubiquitous rag- weed {^Ambrosia artemisicefolia) does not escape. 



Returning to the characteristics of the family, we must notice the 

 striking peculiarity, so far as fungi are concerned, of the production of 



