i66 Bulletin 395 



The conidia are hyaline, and from oblong to elliptical and in some cases 

 slightly dumbbell-shaped. They are characterized by having an oil globule 

 at each end, and they measure from 5 to 7 ju in length by from 2.5 to 3 ju 

 in width. 



NOMENCLATURE 



The conidial stage of the fungus was first collected by Spegazzini in 

 1877 in Italy on Rubus chamaeniorus , and was named by him Gloeosporium 

 venetum. In America the organism was first mentioned by Burrill (1882). 

 He evidently either had not seen Spegazzini's description or considered the 

 two fungi to be distinct, since he gives no name to the pathogene. Burrill 

 states, moreover, that possibly the raspberry fungus belongs to the genus 

 Gloeosporium, but he thinks the fact that the spores are not borne beneath 

 the epidermis throws some doubt on its position. Ellis (Ellis and Everhart, 

 1887) described the fungus under the name Gloeosporium necator E. & E., 

 although previously in a letter to Burrill he had referred it to the genus 

 Ascochyta. The similarity of G. necator E. & E. to G. venetum Speg. 

 was recognized by Ellis, but the two species were separated by him because 

 the latter is foliicolous. From this it is evident that he had not observed 

 the pathogene on the leaves of the raspberry. In the following year 

 Scribner (1888) pointed out the fact that since G. necator E. & E. agrees in 

 all characters with the fungus previously described by Spegazzini, and since 

 it occurs on both the leaves and the canes, it should be known as 

 Gloeosporium venetum Speg. 



In 1 9 14 the writer (191 4) reported the discovery of an ascomycete 



which he regarded as the perfect stage of this fungus, and in a later paper 



(191 7) he showed the connection between the two forms. The fungus 



was given the name Plectodiscella veneta. The only representative of the 



genus Plectodiscella known previous to 191 7 was P. Piri, described by 



Woronichin (191 4) as occurring on the leaves of apple and of pear. The 



morphology of the two species is strikingly similar and it is apparent that 



the ascigerous stage of Gloeosporium venetum belongs in the same genus. 



With the exception of the work of Von Hohnel (1909), but little careful 



investigation has been conducted on this group of ascomycetes, and the 



systematic position of the genus Plectodiscella is somewhat doubtful. 



Woronichin merely places it somewhere between the genus Elsinoe Rac. 



and the true discomycetes. When it is considered that the position of 



Elsinoe is also indefinite, the taxonomic position of the genus Plectodiscella 



becomes more difficult to determine. Both genera, however, show close 



relationship with the order Plectascales, and no doubt should be placed 



there. 



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