A Study of Meadow-Crop Diseases in New York 61 



In 1884, M. C. Cooke says he found a specimen in Berkeley's herbarium 

 (1884:63) bearing elliptical, continuous, hyaline spores, 10 to 12/* by 5/x, 

 in clavate asci. Ellis and Everhart (1892:597) state that all the spec- 

 imens which the^y have seen in America are immature or sterile. Clevenger 

 (1905:160) in a short paper on North American Phyllachoras reports 

 the collection of a fertile specimen having oval, hyaline, 8 to 10/x by 5 to 

 6/u, uniseriate ascospores. 



Theissen and Sydow in their monograph of the Dothideales (1915:511) 

 refer the specimen described by Clevenger to P. umbilicata n. sp. on the 

 basis of differences in the stroma. They retain P. trijolii but as a sterile 

 form. 



Killian (1923) first saw and reported mature ascospores of this fungus. 

 He wintered the stromata and obtained perithecia with 2 to 4 large fusiform 

 asci containing 8 hyaline, bicellular spores, 26 by 6/jl elongated, and 

 slightly curved. Since the genus Phyllachora has continuous spores, he 

 transferred the clover fungus to Plowrightia of the hyalodidymae of the 

 Dothideales. Killian obtained infection with ascospores. By obtaining 

 infection with the spores he demonstrated that the so-called spermogonia 

 are really pycnidia. 



A year later, in 1924, two English workers, Bayliss-Elliott and Stans- 

 field, unaware of Killian's work, overwintered stromata that produced 

 perithecia containing asci with 2-celled hyaline spores measuring 24 to 

 26/x by 7ju to 8/z. The authors point out, in a footnote at the end of their 

 paper, however, that Dothidella Speg. is the correct generic name since 

 it antedates Plowrightia Sacc. A Latin description therefore is given 

 of Dothidella trijolii (1924:227). 



In the autumn, Bayliss-Elliott and Stansfield found 1-celled hyaline 

 ascospores in their material. This indicates that the spores which Cooke 

 (1884:63) found in Berkeley's herbarium and those which Clevenger 

 found lack the septum because of immaturity. Probably, therefore, 

 I'ln/llachora umbilicata Theiss. & Sydow is a synonym of Dothidella trijolii 

 (Fr.) Bayliss-Elliott and Stansfield. 



Only one other report of historical interest need be recorded here, that 

 is, Polythrincium trijolii var. platensis Speg. on Trijolium platense (Speg- 

 azzini, 1911:437). The word platensis appears to be a typographical 

 error. 



Pathogenicity. A great many attempts bjr the writer to culture D. 

 trijolii have been made, using a varying technic that included spore dilu- 

 tion in acidified agar containing oat, potato, or clover decoctions and 

 plantings of tissue that had been sterlized in mercuric chloride or calcium 

 hypochlorite for varying lengths of time. Uniform failure has rewarded 

 these efforts. Killian in France (1923) got similar results. Successful 

 inoculations with conidia from leaves have been obtained in the green- 



