A NEW SPECIES OF ALTERNARIA 



L. L. Harter 



Forsythia suspensa Thunb. is not a native of the United States, 

 but is an introduction from China. It is grown as an ornamental 

 shrub in this country and is fairly common in the District of 

 Columbia on government ground and in private gardens. The 

 different species of Forsythia are very free from fungous dis- 

 eases, F. suspensa being especially so. 



On November n, 1910, the writer collected the fungus de- 

 scribed below on the leaves of many plants which were growing 

 in a dense cluster on the Mall near Thirteenth Street and just 

 south of the green houses belonging to the United States Depart- 

 ment of Agriculture. Hundreds of plants were grown in the 

 cluster where the specimens were collected and probably seventy- 

 five per cent, of the leaves were affected. From the general char- 

 acter of its growth the fungus is strongly suspected as being a 

 parasite. 



The spots caused by the fungus occur indiscriminately over the 

 surface of the leaf. They are subcircular in outline, gray to 

 grayish-brown in color, and surrounded by dark-brown or dead 

 areas. One or more concentric rings are formed about the gray- 

 ish spots, within which are collected minute black tufts irregularly 

 distributed and visible to the naked eye. The concentric rings, 

 characteristic of some species of this genus, occur only on the 

 upper surface, while the tufts are present on both the upper and 

 lower surfaces. 



Alternaria Forsythiae sp. nov. 



Caespitulis amphigenis, numerosis, plerumque epiphyllis ; ma- 

 culis subcircularibus, griseis vel griseolo-brunneis, concentrice 

 zonatis 2-10 mm. diameter; hyphis fasciculatis, erectis, septatis, 

 tortuosis, olivaceis ; conidiis, acrogenis, clavatis, olivaceo-brunneis, 

 catenulatis, muriformibus, ad septa constrictis 18-60 X 10-16. 5 p,- 

 isthmis 5-15 



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