A PHYLLACHORA OF THE ROYAL PALM 



John R. Johnston and Stephen C. Bruner 

 (With Plate 2, Containing 2 Figures) 



Recently while examining- some royal palms (Roystonea regia 

 Cook) near Rincon, Cuba, the writers were attracted by a fungus 

 which formed conspicuous black, carbonaceous masses several 

 centimeters long on the midribs of the leaves. These masses were 

 seen to be made up of more or less confluent groups of stromata 

 developed in a closely crowded condition beneath the epidermis 

 of the host. The fungus was also present on the leaf-segments 

 but here the growth was more restricted and less conspicuous 

 than on the midrib. 



A study of this fungus showed it to be a Phyllachora and, so' 

 far as could be determined from an examination of the avail- 

 able literature, distinct from any previously described species. 

 It is distinguished from the other species occurring on the Palmae 

 chiefly by the large size of its asci. 



The economic importance of the fungus appears to be slight. 

 It has as yet been observed on only a few plants and the damage 

 to these was not serious. A technical diagnosis is offered, as 

 follows : 



Phyllachora Roystoneae sp. nov. 



Stromata subcutaneous, united to parenchyma and epidermis, 

 black, carbonaceous, gregarious, collected in elongate, subcon- 

 fluent to confluent groups commonly 2-5 cm X 1-6 mm., the sep- 

 arate stromata subcircular to elliptic, convex to conic-convex, com- 

 monly 0.3 to' 1 mm. in diameter, phyllogenous ; perithecia formed 

 as locules in the stroma, subglobose, crowded, in one layer, 26a- 

 430 fx in diameter, the ostioles erumpent, indistinct or slightly 

 papilliform; asci clavate, rounded or subapplanate at the apex 

 stipitate, 1 16-186 X 12-20 /x, eight-spored ; paraphyses absent or 

 soon evanescent; spores irregularly monostichous to subdistich- 

 ous, fusiform, sub-acute at each end, hyaline, thin-walled, stuffed 



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