BOTANICAL GAZETTE. 31 



and Algiers. After giving an account of the morbid appearances 

 produced in the vines and a sketch of the development of the Per- 

 onospora and its mode of propagation, he states that the evil effects 

 of the Peronospora are much greater in Algiers than in France. In 

 the former country the fungus makes its appearance in May, causes 

 the leaves to wither, and exposes the young grapes to the burning 

 sun. The activity of the disease disappears in July. In the region 

 of Bordeaux the mildew also appears early in the season and some- 

 times with such virulence that the conidial tufts appear not only 

 on the leaves and young stems but also on the flowers and young 

 berries, on which parts, as far as I know, the fungus has never been 

 observed in this country. Prof. Prillieux, however, does not tHink 

 that the harm done by "the Peronospora is very great to the wine 

 crop, for the danger is not so much from injury to the grapes as 

 from injury to the nutrition of the vines by the premature fall of 

 the leaves. Admitting that in exceptionally moist years serious 

 trouble might arise, he thinks that in ordinary years the dry weather 

 of midsummer would prevent marked injury from the growth of the 

 Peronospora. 



The use of lime having been proposed by Prof. Garovaglio, of 

 Pavia, as a remedy, M. Prillieux experimented with powdered lime 

 sprinkled on the leaves, but he found no beneficial effects. Even 

 when the spots on the leaves where the Peronospora appeared were 

 cauterized new conidial tufts appeared on the margin of the spots. 

 Experiments with antiseptic fluids sprinkled on the leaves were 

 without satisfactory results. As a practical measure it is advised to 

 burn the leaves affected, because the oospores contained in them 

 carry the disease over to the next season. Oospores have been 

 found by Millardet and Prillieux in grape leaves in France, and the 

 latter thinks that they occur abundantly. It is not improbable 

 that they are abundant in this country, but owing to the density 

 and hairiness of the leaves of most of the varieties of grape culti- 

 vated in this country it is almost impossible to detect their presence 

 with the naked eye or a hand lens, and, as far as my own experience 

 goes, examinations with the compound microscope show oospores 

 only in a comparatively small number of leaves. A continued observ- 

 ation of the disease as it occurs in New England has failed to con- 

 vince me that any perceptible injury is done to the vines in that region 

 where the short and unusually dry summers are unfavorable to the 

 full development of the Peronospora. Dr. Engelmann, however, 

 states that the fungus produces injury in some of the Western States. 

 In Algiers, where the conditions are very different from those of New 

 England and favor the appearance of the fungus early in the sea- 

 son, the disease, as might be expected, is most disastrous.— W. G. 

 Faklow. 



Chrysogonum Virginianum, var. dentatum— I wish to direct 

 the attention of botanists in the lower Middle and Southern States 



